Mr. Fletcher vs. Mr. Daubert: A Jour­ney into the Surreal

By:  Fred­eric White­hurst, J.D., Ph.D.

Many a defense attor­ney has looked in amaze­ment at the court­room “iden­ti­fi­ca­tion” of Cannabis Sativa L. by a law enforce­ment offi­cer sport­ing a gilded pot metal badge and a high school diploma who has writ­ten a report that would turn a ninth grade Eng­lish teacher’s hair gray and deny that same offi­cer a high school diploma. Obvi­ously the award­ing of a Basic Law Enforce­ment Train­ing (BLET) diploma ele­vates such high school grad­u­ates to the doc­toral level in botany, enabling them to con­duct a visual leaf archi­tec­tural analy­sis and the court accepted alchemy of the Duquenois Levine test to reach a con­clu­sion that the green veg­etable mate­r­ial in that lit­tle baggy can be iden­ti­fied as mar­i­juana to the exclu­sion of all other plant mate­r­ial. On the face of it, this iden­ti­fi­ca­tion screams to our com­mon senses as not being pos­si­ble. How­ever, we find that in State v. Fletcher, 92 N.C. App. 50, 373 S.E. 2d 681 (N.C. App. 1988), our courts in North Car­olina are will­ing to accept this tes­ti­mony as evi­dence. Though State v. Ward, 364 N.C. 133 (2010) began a foray into rec­og­niz­ing the ridicu­lous­ness of the legit­i­macy of visual iden­ti­fi­ca­tion of con­trolled sub­stances in a world full of coun­ter­feit mate­ri­als, State v. Gar­nett, ___ N.C. App. ___, 706 S.E.2d 280 (2011) backed away from Ward, thus allow­ing an in-court iden­ti­fi­ca­tion of cannabis sativa to be admis­si­ble. This all flies in the face of a long list of sci­en­tific lit­er­a­ture and even State v. Tate, 300 N.C. 180 (1980), which found that the then known list of mate­ri­als caus­ing false pos­i­tives with this Duquenois chem­i­cal spot test ren­dered the test not sci­en­tif­i­cally reli­able or admis­si­ble as an means of iden­ti­fy­ing mar­i­juana. In North Car­olina we are now given a new stan­dard for admis­si­bil­ity of scientific/expert tes­ti­mony in courts of law. Rule 702 has entered the mod­ern era. As of Octo­ber 1, 2011, the amend­ments to Chap­ter 8C, Rule 702(a) read:

If sci­en­tific, tech­ni­cal or other spe­cial­ized knowl­edge will assist the trier-of-fact to under­stand the evi­dence or to deter­mine a fact in issue, a wit­ness qual­i­fied as an expert by knowl­edge, skill, expe­ri­ence, train­ing, or edu­ca­tion, may tes­tify thereto in the form of an opin­ion, or oth­er­wise, if all of the fol­low­ing apply:
1. The tes­ti­mony is based upon suf­fi­cient facts or data.
2. The tes­ti­mony is the prod­uct of reli­able prin­ci­ples and meth­ods.
3. The wit­ness has applied the prin­ci­ples and meth­ods reli­ably to the facts of the case.

So let us now con­sid­ered this “expert iden­ti­fi­ca­tion” of Cannabis Sativa L. by a BLET “Ph.D. botanist”. The expert must be qual­i­fied by knowl­edge, skill, expe­ri­ence, train­ing or edu­ca­tion. The law enforce­ment offi­cer who has seized green veg­etable mate­r­ial on ten or ten thou­sand occa­sions is not test­ing his qual­i­fi­ca­tions or his “iden­ti­fi­ca­tion pro­to­col”. He is sim­ply seiz­ing green veg­etable mate­r­ial. Let’s con­sider the data that he has at the point of seizure.
The most preva­lent form of seized and “iden­ti­fied as mar­i­juana” mate­r­ial that we see is the mate­r­ial that has been finely crushed. What this means is that the law enforce­ment offi­cer has seized a mate­r­ial which no longer has the macro­scopic char­ac­ter­is­tics of the orig­i­nal plant (if indeed the seized mate­r­ial is plant mate­r­ial). But is it plant mate­r­ial? What is a plant and there­fore veg­etable mate­r­ial? Ask any dic­tio­nary. The Amer­i­can Her­itage Dic­tio­nary defines a plant as “an organ­ism of the veg­etable king­dom, char­ac­ter­is­ti­cally hav­ing cel­lu­lose cell walls, grow­ing by syn­the­sis of inor­ganic sub­stances and lack­ing loco­mo­tion.” Good­ness gra­cious, look it up. We all have dic­tio­nar­ies. And at that point we are see­ing the flaw in the law enforce­ment officer’s qual­i­fi­ca­tions. We ask, “Do you carry a micro­scope?” I’m not being ridicu­lous. A plant mate­r­ial (veg­etable mate­r­ial) con­tains cells. With­out a micro­scope one can not see those cells. So what expe­ri­ence does the offi­cer have in con­duct­ing micro­scopic analy­sis? If none, then we must con­clude that he does not have the req­ui­site expe­ri­ence, train­ing or skill needed to qual­ify as an expert in iden­ti­fy­ing plant mate­r­ial. Of course he can opine that the mate­r­ial he has seized lacks loco­mo­tion but so does road kill, so do rocks, so does a fake plas­tic plant. At a recent CLE sem­i­nar at which I taught, before my lec­ture I went out into the hotel where the CLE was held and broke off a small part of a dec­o­ra­tive plas­tic pot­ted plant. Dur­ing the lec­ture I pulled this pur­loined “veg­etable” mat­ter from my coat pocket and handed it to the man in front of me and asked him what kind of plant it was. He advised that he knew it was a plant but did not know what kind of plant.

Let us get beyond the issue of whether the law enforce­ment offi­cer car­ries a micro­scope as well as or instead of a gun. Let’s sup­pose that the offi­cer in Gar­nett actu­ally had a micro­scope on the wit­ness stand and was able to see cell struc­ture. Let’s give him the ben­e­fit of the doubt that he was not will­ing to give to our client. What would be the next step in this “iden­ti­fi­ca­tion” that is being con­ducted by the offi­cer who is qual­i­fied by train­ing, skill, edu­ca­tion, etc.. We know that mar­i­juana is a seed bear­ing plant. What did the offi­cer see that indi­cated to him that this seized mate­r­ial was a seed bear­ing plant? Did he see any seeds at all? And if he did see objects that he thought were seed what qual­i­fi­ca­tions does he have to rec­og­nize these objects as seeds. Has he con­ducted any research what-so-ever in the visual iden­ti­fi­ca­tion of mar­i­juana seeds? The answer to that ques­tion is absolutely not. In fact there was no research in this area at all any­where until about 2009 when Jenna Fussell, John Thorn­ton and Fred­eric White­hurst authored “The Visual Char­ac­ter­i­za­tion and Iden­ti­fi­ca­tion of Cannabis sativa (Mar­i­juana) Seeds pub­lished in the Jour­nal of Foren­sic Iden­ti­fi­ca­tion 59 (5) 2009. So that leaves out the seeds issue and the offi­cer can not tes­tify that he has skill in iden­ti­fy­ing mar­i­juana seeds. Very likely at this point we have an offi­cer on the stand or at the point of seizure who has no expe­ri­ence or train­ing or skill at “iden­ti­fy­ing” mar­i­juana based upon the char­ac­ter­is­tics we shall call “plant” and “seeds.”

Let’s give the offi­cer the ben­e­fit of the doubt that he did not give our clients. Let’s assume that he has con­ducted research and has the skills needed to iden­tify a mate­r­ial as a plant based upon an accepted def­i­n­i­tion of the word “plant” and he has con­ducted the research and has the skills needed to iden­tify the “seeds” that he sees as seeds from a mar­i­juana plant. So next we reach the issue of flow­ers. Mar­i­juana has flow­ers. Those of us who have been involved in legal cases where “mar­i­juana” was seized have a com­mon sense that mar­i­juana has flow­ers. So we must ask the offi­cer what expe­ri­ence and skill he has in “iden­ti­fy­ing” mar­i­juana flow­ers. And not nec­es­sar­ily even the flow­ers on the grow­ing plant but the flow­ers in the end prod­uct, that which on the street is rec­og­nized as the qual­ity prod­uct because of its high tetrahy­dro­cannabi­nol (THC) con­tent. Who wants leaves and stems and stalks when one can pur­chase the bud/flower? But what is a flower? Can the offi­cer iden­tify the parts of a flower? What skill and train­ing has he got to make him qual­i­fied to ren­der an opin­ion that the mate­r­ial he is observ­ing is even flower mate­r­ial much less mar­i­juana flower mate­r­ial? “I just know it when I see it” is a great response but the obvi­ous query is “Just what is it that you are see­ing and how does that com­pare with the struc­ture of the mar­i­juana flower?” In “The Struc­ture of Eco­nomic Plants”, Pro­fes­sor Her­man Hay­ward tells us that “Hemp is dioe­cious and the num­ber of sta­mi­nate and pis­til­late plants is rel­a­tively con­stant under nor­mal con­di­tions.” And describ­ing the sta­mi­nate inflo­res­cence and flower, Hay­ward tells us that ”the flow­ers develop in small, droop­ing, branched pan­i­cles, which arise in the axils of foliage leaves. The flow­ers of the pan­i­cle may occur singly on slen­der pedicels or in groups, and usu­ally the ter­mi­nal branches bear three flow­ers, a median one and two lat­er­als which are sub­tended by bracts or stip­ules. The indi­vid­ual flow­ers are petalous with a deeply parted calyx hav­ing five greenish-yellow or red lobes that are wide­spread at matu­rity. There are five sta­mens, and the anthers are sus­pended from long thread-like fil­a­ments.” This, of course describes the flow­ers in their grow­ing state, not in the state that one finds them on the street. The expe­ri­enced law enforce­ment offi­cer who has the skill, train­ing, knowl­edge, etc. to qual­ify him as an expert who can offer an opin­ion that what he is look­ing at is mar­i­juana flower, of course knows all of this and more and will be able to describe all of those parts that he is see­ing that fit Hayward’s very clear descrip­tion of grow­ing mar­i­juana plant flow­ers. If not then he does not have the req­ui­site expe­ri­ence, train­ing or skill. And if the offi­cer can rec­og­nize all the parts of mar­i­juana flower are present within the mate­r­ial he has seized and is call­ing mar­i­juana, we must still ask if he has the req­ui­site expe­ri­ence and train­ing to not only rec­og­nize the parts but tell us that no other plants has such parts, not no other plant he has seen, but no other plant. He has been asked to iden­tify the plant as mar­i­juana, mean­ing that he is say­ing that the plant is mar­i­juana to the exclu­sion of all other plants or at least a rea­son­able por­tion of the other plants on the planet.

This is not cannabis. It is Kenaf of Kanap that contaons no THC

This is not cannabis. It is Kenaf of Kanap that con­taons no THC

But again, let’s give this offi­cer the ben­e­fit of the doubt that he was not will­ing to extend to our clients and progress to the next level of inquiry about his skill and expe­ri­ence and train­ing. Mar­i­juana is a dicotyle­don as opposed to being a mono­cotyle­don. Does the offi­cer know what this means? Surely with the proper train­ing, skill and expe­ri­ence he does. In fact, if he remem­bers his ninth grade biol­ogy class he will real­ize what these terms mean. A cotyle­don is the part of the plant that nour­ishes the embry­onic plant until it can suc­ceed on its own. In North Car­olina, an agri­cul­tural state, all of us should know about open­ing up peanuts or lima beans. Two halves, fat leaves, inside of which exists a tiny lit­tle plant. (If you haven’t opened up a lima bean you haven’t lived. Go do it now.) Those two halves are cotyle­dons and because there are two of them we call plants with two of them, dicotyle­dons. Plants such as corn have only one lit­tle fat leaf, one cotyle­don, the ker­nel of corn, that feed the lit­tle corn plant until it grows into the stalk on which the corn is pro­duced. So, assum­ing the offi­cer remem­bers his ninth grade biol­ogy class, he will have the req­ui­site knowl­edge and skill needed to rec­og­nize if this plant is a dicotyle­don, which mar­i­juana is. But how many other plants are there that are dicotyle­dons? Does he know this? Can he prop­erly edu­cate a trier-of-fact to the poten­tial num­ber of plants that might be mis­taken for mar­i­juana based on the char­ac­ter­is­tics we have con­sid­ered thus far?

Please remem­ber that what the offi­cer seizes most often is crushed mate­r­ial, no longer hav­ing all the char­ac­ter­is­tics of the grow­ing plant. Dur­ing the prepa­ra­tion for dis­tri­b­u­tion, the flow­ers are left whole but the leaves are crushed into very small pieces. A “leaf archi­tec­tural analy­sis” is no longer pos­si­ble. Go out into the woods right now or out into your yard. Pick leaves off a num­ber of plants. Let them dry a bit and then crush them up. Ask your­self if you can then tell from which plant those crushed up leaves orig­i­nated. You might be able to dif­fer­en­ti­ate crush yard grass or corn leaves from oak leaves but can you dif­fer­en­ti­ate live oak leaves from red oak leaves from maple? Can you dif­fer­en­ti­ate oregano leaves from tea leaves just by look­ing at them? Does the offi­cer have the skill, train­ing and edu­ca­tion to do this? Hickey in the Jour­nal of Botany, 60(1): 17–33 (1973) describes for us this leaf archi­tec­tural analy­sis. Has the offi­cer the skill, knowl­edge or train­ing in this area? Leaves are clas­si­fied accord­ing to leaf ori­en­ta­tion, orga­ni­za­tion, shape, mar­gin, tex­ture, gland posi­tion, peti­ole, types of vena­tion, and ele­ments of tooth archi­tec­ture. When we fol­low Hicky we being to look at the form of leaf mar­gin; we see clas­si­fi­ca­tion con­cepts such as entire, lobed, toothed, cre­nate, erose, rev­o­lute or enrolled, sinuses, spac­ing and series. Does the offi­cer know what these con­cepts even mean? But wait! These are gen­er­ally not seized plants that we have in evi­dence but crushed up mate­r­ial. So how do we begin to con­duct Hickey’s sug­gested leaf archi­tec­tural analy­sis? What train­ing, expe­ri­ence or skill can the offi­cer tes­tify to to be qual­i­fied in the “iden­ti­fi­ca­tion” of mar­i­juana from a leaf archi­tec­tural analy­sis when the leaves are no longer in their nat­ural state? In his paper “Foren­sic Aspects of Cys­tolith Hairs of Cannabis and Other Plants”, Jour­nal of AOAC (Vol. 52, No.1, 1969), George Naka­mura noted that even with a micro­scopic analy­sis he could not dif­fer­en­ti­ate 82 dif­fer­ent seed bear­ing plants out of 31874 he con­sid­ered. He never con­sid­ered a leaf archi­tec­tural analy­sis because, obvi­ously once the leaves are crushed up into prod­uct for street sales, such an analy­sis would not be pos­si­ble. So how can a law enforce­ment offi­cer visu­ally iden­tify green veg­etable mate­r­ial as mar­i­juana even with a microscope?

The response this author has heard in the past has been that one need not be a botanist in order to under­stand botan­i­cal con­cepts. OK, but Rule of Evi­dence 702 now requires that

If sci­en­tific, tech­ni­cal or other spe­cial­ized knowl­edge will assist the trier-of-fact to under­stand the evi­dence or to deter­mine a fact in issue, a wit­ness qual­i­fied as an expert by knowl­edge, skill, expe­ri­ence, train­ing, or edu­ca­tion, may tes­tify thereto in the form of an opin­ion, or oth­er­wise, if all of the fol­low­ing apply:
1. The tes­ti­mony is based upon suf­fi­cient facts or data.
2. The tes­ti­mony is the prod­uct of reli­able prin­ci­ples and meth­ods.
3. The wit­ness has applied the prin­ci­ples and meth­ods reli­ably to the facts of the case.

Cannabis Sativa L. is an extremely com­plex organ­ism which shares many fea­tures in com­mon with many other plants. We are informed by Ivan Ross in “Med­i­c­i­nal Plants of the World, Chem­i­cal Con­stituents, Tra­di­tional and Mod­ern Med­i­c­i­nal Uses” Vol­ume 3 that over 500 known chem­i­cal con­stituents have been iso­lated and iden­ti­fied in mar­i­juana. We are informed by Robert Thorne in “How Many Speci­cies of Seed Plants Are There”, Taxon 51, August 2002, that there are con­ser­v­a­tively 258,650 known seed bear­ing plants. If we refer to the Ency­clo­pe­dia Bri­tan­nica we see esti­mates of 200,000 to 500,000 known seed bear­ing plants. When we iden­tify mar­i­juana we are say­ing that the data we have col­lected is suf­fi­cient to iden­tify the mate­r­ial to the exclu­sion of any other plant or at least to the exclu­sion of a rea­son­able num­ber of other plants. We are say­ing that the com­bi­na­tion of fea­tures we have observed are only seen in mar­i­juana. Does the iden­ti­fy­ing offi­cer have the skill, edu­ca­tion, knowl­edge or train­ing to be able to artic­u­late why the fea­tures he is observ­ing would not be observed in that com­bi­na­tion in any other plant mate­r­ial? And has he col­lected suf­fi­cient data to deter­mine the mate­r­ial he has iden­ti­fied as mar­i­juana is in fact mar­i­juana. In Gar­nett the offi­cer sim­ply looked at the green veg­etable mate­r­ial and did not deter­mine if it was a plant mate­r­ial in a reli­able man­ner. The opin­ion does not address the pro­to­col the offi­cer fol­lowed in deter­min­ing if the mate­r­ial was a seed bear­ing mate­r­ial, if the mate­r­ial was a flow­er­ing plant or a dicotyle­don, if the offi­cer con­ducted a leaf archi­tec­tural analy­sis or an analy­sis of any poten­tial flower mate­r­ial in the evi­dence. In the words of Rule 702, is it true that “The tes­ti­mony is based upon suf­fi­cient facts or data?”, to say that this com­bi­na­tion of fea­tures would be observed in no other plant. And what fea­tures are we talk­ing about. Green veg­etable mate­r­ial? Unique odor?

How does one deter­mine if the odor the offi­cer is detect­ing is unique to mar­i­juana? Does the offi­cer have the expe­ri­ence, train­ing, skills or edu­ca­tion to say that the odor that he is detect­ing (what­ever that is) is unique to mar­i­juana. The offi­cer may very well tes­tify that he has never smelled any­thing else that smells like mar­i­juana. How does one test that state­ment? The officer’s olfac­tory senses can be tested but have they been tested? Is there suf­fi­cient data from the olfac­tory analy­sis from the offi­cer that the court can deter­mine the admis­si­bil­ity of the evi­dence or even the weight of the evi­dence? In other words, is the tes­ti­mony the prod­uct of reli­able prin­ci­ples and meth­ods and did the offi­cer prop­erly apply those prin­ci­ples and meth­ods to the facts of the case. It would be vir­tu­ally impos­si­ble for the trial court to test the officer’s olfac­tory senses and I am not aware of any police agency that tests for olfac­tory senses in its offi­cers. Flem­ming et. al. in “Top­ics in Het­e­ro­cyclic Chem­istry”, Vol­ume 10, 1–42 (2007) inform us that there are 120 susquiter­penoid and ter­penoid com­pounds which com­pose the mate­ri­als which are detected as the “odor” of mar­i­juana. Any Google search of sites that pur­port to sell mar­i­juana or its seeds for pro­duc­tion adver­tise their prod­ucts accord­ing to effect on the body, appear­ance and odor. It is rea­son­able to believe that envi­ron­men­tal impact will alter the qual­i­ta­tive and quan­ti­ta­tive enve­lope of the chem­i­cal com­po­si­tion of Cannabis Sativa L.. One need only look at the results of the use of such prod­ucts as Mir­a­cle Grow on a home gar­den to real­ize that envi­ron­men­tal fac­tors play a very big role in plant com­po­si­tion. The Court may very well be left with no way of deter­min­ing if the odor detec­tion part of the mar­i­juana analy­sis pro­to­col is reli­able? And the Court would do well to ask this, “Why does or did the North Car­olina Crime Lab ever con­duct a mar­i­juana analy­sis if an offi­cer need only smell the green veg­etable mate­r­ial to prove it is mar­i­juana”? It defies logic.

D.W. John­son and J.W. Gunn in Dan­ger­ous Drugs, Adul­ter­ants, Dilu­ents and Decep­tion in Street Sam­ples” , Jour­nal of Foren­sic Sci­ence, 1972 found that up to 20% of the alleged mar­i­juana sam­ples sub­mit­ted to the US Depart­ment of Justice’s Bureau of Nar­cotics and Dan­ger­ous Drugs lab were not in fact mar­i­juana. Though I have not found any more recent data describ­ing the occur­rence of coun­ter­feit mar­i­juana being sub­mit­ted by law enforce­ment offi­cers as mar­i­juana to crime labs, North Car­olina Gen­eral Statutes accept that coun­ter­feit con­trolled sub­stances are in fact a very real prob­lem and are deemed to be ille­gal. We must ask how many times law enforce­ment offi­cers sub­mit mate­r­ial they sus­pect of being mar­i­juana to a crime lab and the mate­r­ial is found to not be mar­i­juana. In other words, has any­one deter­mined the error rate for an analy­sis of sus­pected mar­i­juana con­ducted by a law enforce­ment offi­cer visu­ally and chem­i­cally ana­lyzed mar­i­juana or worse, sim­ply visu­ally deter­min­ing the green veg­etable mate­r­ial is marijuana.

In sum­mary, Fletcher meets Daubert (or in North Car­o­line Rule of Evi­dence 702) and leaves us very only with ques­tions, ques­tions that should be answered before a North Car­olina Court can accept an officer’s “iden­ti­fi­ca­tion” of mar­i­juana sim­ply by a visual or olfac­tory test. If a defen­dant wishes to stip­u­late that the mate­r­ial that was in his pos­ses­sion was mar­i­juana then the ques­tion is closed. How­ever, do we know even if defen­dants are capa­ble of deter­min­ing that they have not been sold coun­ter­feit mate­r­ial? Remem­ber that there is a new test of reli­a­bil­ity now in North Car­olina which must be sat­is­fied before sci­en­tific, tech­ni­cal or other spe­cial­ized knowl­edge will be admit­ted as evidence.

If sci­en­tific, tech­ni­cal or other spe­cial­ized knowl­edge will assist the trier-of-fact to under­stand the evi­dence or to deter­mine a fact in issue, a wit­ness qual­i­fied as an expert by knowl­edge, skill, expe­ri­ence, train­ing, or edu­ca­tion, may tes­tify thereto in the form of an opin­ion, or oth­er­wise, if all of the fol­low­ing apply:
1. The tes­ti­mony is based upon suf­fi­cient facts or data.
2. The tes­ti­mony is the prod­uct of reli­able prin­ci­ples and meth­ods.
3. The wit­ness has applied the prin­ci­ples and meth­ods reli­ably to the facts of the case.”
Street and/or court­room “iden­ti­fi­ca­tion” of green veg­etable mate­r­ial being mar­i­juana in no way meets that test.

In 2006, more than 829,000 peo­ple were arrested in this coun­try for marijuana-related offenses alone. Since 1937 with the pas­sage and adop­tion of the Mar­i­huana Tax Act, mar­i­juana has been effec­tively pro­hib­ited in the United States.

Lit­er­ally mil­lions upon mil­lions of peo­ple have been accused of pos­sess­ing mar­i­juana. The ques­tion becomes are these con­vic­tions sci­en­tif­i­cally supported?

In this series of posts we are going to exam­ine this seemly sim­ple question:

  1. What is the goal and the pur­pose of test­ing of unknowns gen­er­ally? How do we best design a test for marijuana?
  2. How is most mar­i­juana test­ing con­ducted in the United States?
  3. What is micro­scopic mor­pho­log­i­cal exam­i­na­tion? Is it a “good” test?
  4. What is the mod­i­fied Duquenois-Levine test? Is it a “good” test?
  5. What is Thin Layer Chro­matog­ra­phy? Is it a “good” test?
  6. Is the com­bi­na­tion of all three tests cre­ate a “good” test­ing scheme?
  7. Is there a bet­ter way to test for marijuana?

Part 2: How is most mar­i­juana test­ing con­ducted in the United States?

So what hap­pens in Amer­ica, here, now and today in the iden­ti­fi­ca­tion of marijuana?

  • Are the tests pre­sump­tive or confirmatory?
  • Are the meth­ods used verifiable?
  • Does it result in a spe­cific or selec­tive identification?

Let’s take a look at how mar­i­juana is tested in the United States today in the super-majority of cases. It all begins with a police offi­cer or another per­son who seizes an unknown sub­stance. It’s green. It’s veg­etable like. It looks like mar­i­juana to them. Per­haps they do some sort of quick and dirty test on the side of the road using a fast col­ori­met­ric test and there is a change in color. This is a true unknown. We don’t know what it is. We can­not con­clude what it is based upon sim­ply look­ing at it with our own two eyes or even by our sense of smell. This is why we have foren­sic sci­en­tists and fur­ther test­ing because those types of obser­va­tions may lead to an improper or incor­rect result.

attempts at identifying marijuana at the gross or macro level can be misleading

Attempts at iden­ti­fy­ing mar­i­juana at the gross or macro level can be misleading

A basic fun­da­men­tal ques­tion becomes: What makes mar­i­juana ille­gal to pos­sess? What makes mar­i­juana ille­gal is that it con­tains the phar­ma­co­dy­nam­i­cally sub­stance known as Delta-9 Tetrahy­dro­cannabi­nol (THC).

Given that THC is what makes mar­i­juana ille­gal, then log­i­cally what would be best is if we were design tests that react exclu­sively to THC and noth­ing else and pro­duces ver­i­fi­able data that iden­ti­fies that the green veg­etable sub­stance in fact specif­i­cally con­tains THC.

Because we can’t tell what it is just by look­ing at it or just by smelling it, then we must sub­ject this unknown to test­ing. Largely in the United States there is a régime or process of how crime lab­o­ra­to­ries con­duct this test­ing. The triad of test­ing that is con­ducted are:

  1. Micro­scopic mor­pho­log­i­cal examination
  2. Mod­i­fied Duquenois-Levine testing
  3. Thin Layer Chromatography

This is gen­er­ally referred to as the Thorton-Nakumura protocol.

In order to answer our ques­tions of speci­ficity, ver­i­fi­ca­tion, and con­fir­ma­tory we need to look at each of these three test­ing tech­niques. In our next blog posts over the next sev­eral weeks each of these tests will be scrutinized.

The great Bard once penned:

All: God save your majesty!

Cade: I thank you, good people—there shall be no money; all shall eat and drink on my score, and I will apparel them all in one liv­ery, that they may agree like broth­ers, and wor­ship me their lord.

Dick: The first thing we do, let’s kill all the lawyers.

Cade: Nay, that I mean to do.

Henry The Sixth, Part 2 Act 4, scene 2, 71–78

Shakespeare’s char­ac­ter Dick the Butcher’s idea of a per­fect soci­ety was one where jus­tice pre­vailed because there were no lawyers. The trai­tor­ous Jack Cade had not so noble a rea­son for want­ing to get rid of all of the lawyers. He wanted to become the auto­crat in a quasi-communistic social rev­o­lu­tion. Cade alleges that all lawyers do is use laws and lan­guage set up by fel­low lawyers to oppress and ruin the life of every day man. There­fore, in his esti­ma­tion, no jus­tice results.

That is an extreme view.

I sug­gest that per­haps jus­tice best results when we have an edu­cated and orga­nized defense bar who is sci­en­tif­i­cally edu­cated in foren­sic sci­ence. As I have blogged before, the foren­sic sci­ence com­mu­nity as cur­rently prac­ticed in the United States today is very flawed. Extremely flawed. Fun­da­men­tally flawed. In some cases, if not the major­ity of cases, it is utterly unsci­en­tific. I agree with the sen­ti­ments that the crim­i­nal defense com­mu­nity shares a large por­tion of the blame. Many lawyers well before our times, let come into evi­dence prac­tices, tech­niques, and “the­o­ries” that had just but the very veneer of sci­ence and were, how­ever, any­thing but sci­en­tific and far from valid. This insti­tu­tional prop­a­ga­tion of error is a large hur­dle for many of us to over­come now where busi­ness as usual or sim­ple rep­e­ti­tion is some­how equated with validity.

So what are we to do?

Set up pro­grams where we edu­cate the defense bar.

I would like to high­light one of these: The Amer­i­can Chem­i­cal Soci­ety Hands-on Foren­sic Chro­matog­ra­phy course.

It is a five-days hands-on class con­ducted at Axion Ana­lyt­i­cal Lab­o­ra­to­ries, Inc. in Chicago, Illi­nois. This hands-on course is taught by three icons of chro­matog­ra­phy (Dr. Harold McNair, PhD, Dr. Lee Polite, PhD and Mr. Lew Fox) and two attor­neys who spe­cial­ize in eval­u­at­ing chro­matog­ra­phy and foren­sic sci­ence related cases (Justin J. McShane and Josh D. Lee).

 

The agenda includes:

Day 1

8:15am Reg­is­tra­tion and Snacks
8:30am Intro­duc­tion to Gas Chromatography
9:30am Inlet Sys­tems for Liq­uid Injections
10:30am Lab 1: GC Famil­iar­iza­tion and Parameters
11:45 Lab Review
12:00pm Lunch
1:00pm Fun­da­men­tals of Sep­a­ra­tion — Resolution
2:30pm GC The­ory
3:30pm Cap­il­lary Columns
4:30pm Lab 2: Col­umn Installation
6:00pm End of Session
7:30pm Group Din­ner

Day 2

8:30am Quan­ti­ta­tive Analysis
9:30am Dis­cus­sion of QC in the Foren­sic World
10:30am Lab 3: GC Quantitation
12:00pm Lunch
1:00pm Lab Review
2:00pm Head­space GC
4:00pm Lab 4: Head­space Demo
5:00pm End of Session
6:30pm Axion Labs spon­sored Group Dinner

Day 3

8:30am GC-MS The­ory
10:30am LC-MS The­ory
12:00pm Lunch
1:00pm Labs 5–7: Wet Lab –Sam­ple Preparation/ Inte­gra­tion / GC-MS Instrumentation
3:00pm FID Detec­tor
4:00pm Dis­cov­ery
5:30pm End of Session
7:05pm Sport­ing event

Day 4

8:30am Ethics
9:30am Lab 8: Walk­ing Down a Case-How to Sort, Iden­tify and Exam­ine Data (Con­fronta­tion Clause)
11:00 am Gen­eral Review of Major Concepts
12:00pm Lunch
1:00pm Defenses That Work
3:00pm Lab 9: Trou­bleshoot­ing GC Problems
4:30pm Lab 10: Beers and Data Round­table (Bring your own data set eval­u­ate with your small group)
8:30pm End

 

Day 5

8:30am Trou­bleshoot­ing Lab Review
9:00am Cross exam­i­na­tion of an Analyst
10:30am Direct Exam­i­na­tion of an Expert
12:00pm Trou­ble Shoot­ing Lab Review
12:30pm Soft stop of the course with gen­eral discussion
2:00pm Hard Stop-End of Course

This class attracts full of attor­neys from all across the United States. In this class atten­dees not only are instructed in the class­room the­ory that under­lies chro­matog­ra­phy (both liq­uid and gas chro­matog­ra­phy) in gen­eral and the spe­cific the­o­ries that allow for head­space analy­sis and how Flame Ion­iza­tion Detec­tor, UV-DAD and Mass Spec­trom­e­try (EI and EC based) works, and get to see the instru­ments, but they also get to do the fol­low­ing with their own two hands and more:

Hands-on Lab 1

Instru­ment Famil­iar­iza­tion where the atten­dees pre­form direct injec­tions into a Gas Chromatograph-Flame Ion­iza­tion Detec­tor (GC-FID) using EtOH sam­ples, and learn to inter­pret GC-FID chro­matograms, import and manip­u­late a method, change the dif­fer­ent vari­ables on the GC-FID and elu­ci­date the results.

Hands-on Lab 2

The atten­dees on their own GC machine remove and install cap­il­lary columns and all of the com­po­nents of the injec­tor (septa, liner, gold seal, etc.), check for effi­cien­cies, res­o­lu­tion, the­o­ret­i­cal plates, and learn about split ver­sus split­less injec­tor settings.

Hands-on Lab 3

The atten­dees on their own GC machine estab­lish a cal­i­bra­tion curve from CRMs for EtOH. The atten­dees on their own GC machine ana­lyze the response and pro­gram a cal­i­bra­tion curve (exter­nal stan­dard) and also use the Inter­nal Stan­dard method to assure qual­ity. The atten­dees on their own GC machine estab­lish meth­ods and report­ing of this cru­cial part of testing.

Hands-on Lab 4

The atten­dees con­tinue to use Head­space Gas Chromatograph-Flame Ion­iza­tion Detec­tor and also use Gas Chro­matog­ra­phy Mass Spec­trom­e­try (GC-MS) sys­tem, and use an High Per­for­mance Liq­uid Chro­matog­ra­phy (HPLC) system.

Hands-on Lab 5

Sam­ple Preparation-sampling ver­sus sam­ple selec­tion is demon­strated. The atten­dees do their own Pipet­ting. The atten­dees do their own con­trol chart­ing. The atten­dees use vol­u­met­ric flasks. The atten­dees learn about pre-analysis error hands-on and how it affects quan­tifi­ca­tion. The atten­dees are intro­duced to issues of metrol­ogy and Uncer­tainty Measurement.

Hands-on Lab 6

Inte­gra­tion. The atten­dees on their own Chem­Sta­tion work­sta­tion learn about inte­gra­tion and how easy it is to manip­u­late the data. The atten­dees manip­u­late their own data. The atten­dees learn what to look for that shows that the data was manip­u­lated, and the atten­dees learn how to manip­u­late data so that it is not dis­cov­er­able with­out the raw com­puter data in the soft­ware files.

Hands-on Lab 7

GC-MS Instru­men­ta­tion. The atten­dees see how easy life is for an ana­lyst. The atten­dees get to see the analy­sis of the raw data on a GC-MS and dis­cover how a true novice can turn into an “expert” with a sim­ple push of a but­ton. The atten­dees see with their own two eyes the “hid­den” data that the Gov­ern­ment and its lab­o­ra­tory doesn’t want any­one to see that will reveal the truth that the sup­posed “gold stan­dard” that pro­vides for the alleged “unequiv­o­cal iden­ti­fi­ca­tion” of test­ing of unknowns that is GC-MS is not perfect.

Hands-on Lab 8

How to Obtain Discovery/Walking Down a Case/Defenses that Win-Advanced Issue Spot­ting: In this lab, the best prac­tices in how to obtain dis­cov­ery with a spe­cial empha­sis on how to strate­gi­cally and prac­ti­cally build a record so that the atten­dees can get the raw data in its un-manipulated raw com­puter form and also in its print form. The atten­dees go through an actual case that was lit­i­gated that fea­tured experts on both sides, and issue spot all of the prob­lems with the dis­cov­ery and the data as it was presented.

Hands-on Lab 9

Trou­bleshoot­ing. The atten­dees on their own GC machine run an unknown sam­ple which may result in some sort of “prob­lem” in the chro­matogram. The atten­dees issue spot the prob­lem and ratio­nal­ize what is wrong, and fix it.

Hands-on Lab 10

The atten­dees with their lab part­ners go over their own data set from real cases to fig­ure out what is wrong with the atten­dees’ local laboratory.

Grad­u­ates of the group include:

STATE LAST NAME FIRST NAME   STATE LAST NAME FIRST NAME
Alaska Slone Fred New Jer­sey Her­nan­dez Steven
Ari­zona St. Louis Joe New Jer­sey Levow Evan
Cal­i­for­nia Barba Manny New Mex­ico Frechette Rod­er­ick
Cal­i­for­nia Brehmer Jeremy Okla­homa Edge Bruce
Cal­i­for­nia Ganci Eric Okla­homa Fabian Stephen
Cal­i­for­nia Gore­lick Lynn Okla­homa Hosty Tom
Cal­i­for­nia Laun­dry Vir­ginia Okla­homa Lee (x5)
Josh D.
Cal­i­for­nia Mid­dle­brook Richard Okla­homa Pat­ter­son Clint
Cal­i­for­nia Moore Ron Okla­homa Sifers Jeff
Cal­i­for­nia Sturm Craig Ore­gon Carini, Jr. Peter
Cal­i­for­nia Tie­mann Roland Penn­syl­va­nia Bar­rouk Tim
Cal­i­for­nia Was­son James Penn­syl­va­nia Man­ches­ter Brian
Cal­i­for­nia Wap­ner Terry Penn­syl­va­nia McShane (x6)
Justin
Col­orado Bussey Tim Penn­syl­va­nia Sher­man Mike
Col­orado Cessna Christo­pher Ten­nessee Garza (x2)
Mar­cos
Col­orado Her­ringer William Ten­nessee May Roger
Col­orado Savela Jason Ten­nessee McK­in­ney Rob
Col­orado Orr Rhid­ian Ten­nessee Ryan Edward
Florida Kessler Mike Texas Bal­a­gia Jaime
Florida McIn­tosh Brett Texas But­ler Jim
Geor­gia Adams Clark Texas Boatwright Nicky
Geor­gia Bab­son Rocky Texas Case Kelly
Geor­gia Caron Brian Texas Cof­fey Mimi
Geor­gia Frye Kim Texas de la Paz Brent
Geor­gia Par­man Ann Texas del Cueto Andrew
Geor­gia Stein George Texas DeLuca Matt
Illi­nois Ram­sell Don­ald Texas Flood Tyler
Illi­nois Toney Sarah Texas Grant Dean­dra
Kansas Hul­nick Les Texas Hamil­ton Stephen
Louisiana Delatte (x2)
Glynn Texas Hunter David
Louisiana Bates, Jr. James Texas McK­in­ney Troy
Mary­land Alpert Andrew Texas Mur­phy Doug
Mary­land Bruck­heim Michael Texas Ray Ben­nie
Mary­land Stamm Lenny Texas Segura Anthony
Mass­a­chu­setts Ober­hauser Gre­gory Texas Stauf­fer Phil
Michi­gan Boyle Michael Texas Trichter (x2)
Gary
Min­nesota Ram­say Charles Texas Wilder Dou­glas
Mis­souri East­man Jef­frey Utah Schatz Jason
Mis­souri Holling­shead Jeremy Vir­ginia Keefer Bob
Mis­souri Ward Carl Vir­ginia Solak– (x2)
Michael
Nebraska Dowd­ing Steve Wash­ing­ton Calla­han Linda
Nebraska Island Bell Wash­ing­ton DeBray Ted
Nevada Hayes Dale West Vir­ginia Wag­ner Harley
New Hamp­shire Russ­man Ryan Wis­con­sin Stuck­ert Lau­ren
New Hamp­shire Tenn John

There have been 89 grad­u­ates to date.

The next class (which is full) will be in April is sched­uled to have the fol­low­ing folks:

Patrick Maher

MD

Hunter Bie­der­man

TX

Wayne R. Foote

ME

John Hun­sucker

OK

Andrew Mishlove

WI

Michael J Snure

FL

Clark Adams (2nd time through)

GA

Andrew Bucher

OH

N. Cole Williams

NC

Jay M. Tiftickjian

CO

Bruce Edge (2nd time through)

OK

Brent de la Paz (2nd time through)

TX

Paul Liam McGlone

VA

Kevin Leck­er­man

PA

Jon W Woolsey

CA

Gor­don Senerius

SC

Nico La Hood

TX

Bryan E DePowell

PA

Joseph Cit­ron

GA

John j Eastland

TX

Jonathon Rands

WA

Shawn Dor­ward

PA

Jared Bartell

CA

To insure jus­tice, we need to have an edu­cated defense bar. We need more sci­en­tific pro­grams like this one.

A fre­quently asked ques­tion on the list­servs that I belong to basi­cally asks the fol­low­ing question:

In GC-FID use to quan­tify Blood Alco­hol Con­tent where EtOH is the tar­get ana­lyte, how does the machine arrive at the reported number?

The machine is called a Gas Chro­mato­graph with a Flame Ion­iza­tion Detec­tor (GC-FID). Typ­i­cally the sam­ple is intro­duced by way of head­space. The most fre­quently used tech­nique is tech­ni­cally called Sta­tic Head­space Isother­mal Wall Coated Open Tubu­lar Gas Chro­matog­ra­phy with Flame Ion­iza­tion Detector.

First a crash course on the Flame Ion­iza­tion Detec­tor (FID).

The FID is the part of the appa­ra­tus that quan­ti­tates the result of the chro­mato­graphic efflu­ent. Remem­ber that the num­ber one rule of GC-FID is that you must demon­strate with data (actu­ally prove) proper res­o­lu­tion first. The mea­sure of qual­i­ta­tive selec­tiv­ity (sep­a­ra­tion) must be proven before we can validly quantitate.

The FID actu­ally is a destruc­tive, mass count­ing device. It lit­er­ally burns all carbon-hydogen bonds (C-H bonds) from what comes off the col­umn. The cur­rent is sensed by an elec­trom­e­ter, con­verted to a dig­i­tal form and sent to an out­put device that gives us the peak. It counts the increase in the num­ber of ions between a cath­ode and a diode. A polar­iz­ing volt­age attracts these ions to a col­lec­tor located near the flame. This cur­rent is mea­sured with a high-impedance picoam­me­ter. An elec­trom­e­ter is an elec­tri­cal instru­ment for mea­sur­ing elec­tric charge or elec­tri­cal poten­tial dif­fer­ence. The response is pro­por­tional to the num­ber of C-H bonds. So, there­fore, iden­ti­cal amounts of methanol, ethanol, butanol and hexa­nol would not give equal area count responses. The FID itself emits an ana­log (con­stant) sig­nal; yet, it is reported through a com­puter sys­tem that is dig­i­tal in nature.

There are two main meth­ods of deter­min­ing quan­ti­ta­tion when it comes to GC-FID: (1) Peak height, and (2)Peak area.

Peak Height versus Peak Area

Peak Height ver­sus Peak Area

Peak height is an anti­quated method of quan­tifi­ca­tion that is not used a lot. It harkens back to a time when there were no com­puter pro­grams. Lab­Corp and cer­tain labs in Cal­i­for­nia still use the peak height method. Both are based upon the stan­dard dose response cal­i­bra­tion curve.

In order to deter­mine either peak height or peak area, the cru­cial bound­ary is the baseline.

The baseline and its determination is a crucial bound

The base­line and its deter­mi­na­tion is a cru­cial bound

It is essen­tial to remem­ber that all detec­tors have ana­lyt­i­cal noise. There is no way of record­ing zero. No machine can mea­sure true zero. There is always going to be an off­set. As an aside, this is why on a cal­i­bra­tion curve zero (the ori­gin) can­not be used as a legit­i­mate data point in deter­min­ing the slope which gives us the quantitation.

While there is a peak, there is, of course, sig­nal. As a result dur­ing the act of detec­tion there is no base­line per se. Instead, the com­puter uses an algo­rithm based upon prior input before the peak and “guesses” what the base­line would be if there was no sig­nal. As this is the computer’s guess, is it is sub­ject to inter­pre­ta­tion and error.

When we use the peak area method of quan­ti­ta­tion, then the ques­tion becomes not only where is the base­line, but where does the com­puter begin to cal­cu­late the begin­ning and end­ing of a peak. This is so very important.

As you can see in the above there are ver­ti­cal hash marks that are labeled “start” and “stop,” these are called “tick marks.” This is the other perime­ter that deter­mines peak area.

So in sum the deter­mi­na­tion of the peak area is a func­tion of 3 bounds: (1) the base­line and (2) start­ing tick mark, and (3) end­ing tick mark. Think of them as bound­ary marks.

There are two types of inte­gra­tion: (1) auto-integration and (2) man­ual integration.

If the but­ton pusher uses auto-integration, then the deter­mi­na­tion of the base­line will be cal­cu­lated the same through­out the run. This is what should be done (pro­vided that the use of the auto-integration events is sta­tic and equally applies to the cal­i­bra­tors and the unknowns that are tested and is part of a truly val­i­dated method).

On the other hand, one can use man­ual inte­gra­tion events to manip­u­late the data. This is a func­tion of the end user. This is typ­i­cally a one-time event in that only one chro­matogram is manip­u­lated. It may be some­thing that can be dis­cov­ered by look­ing at the chro­matogram or it may be utterly undis­cov­er­able unless you have the raw data. (Here is a video that shows this con­cept: The case for raw data: “Inte­gra­tion” in Gas Chro­matog­ra­phy: How to make an inno­cent per­son guilty in a DUI case by manip­u­lat­ing the soft­ware Actu­ally at Axion, we dis­cov­ered another 3 ways of manip­u­lat­ing the raw data so it would be undetectable.)

The key func­tion of all of this is that every­thing remain the same in order for the result to be valid. The inte­gra­tion events must be sta­tic in order for the quan­tifi­ca­tion to be valid.

When look­ing at the EtOH peak:

The unknown that is your client’s sam­ple must use the same inte­gra­tion perime­ters as the cal­i­bra­tors. The bound­ary marks used to deter­mine the peak area for the cal­i­bra­tors in their indi­vid­ual chro­matograms must match that of the unknown. If the base­line remains the same, but the tick marks are wider for the cal­cu­la­tion of the unknown than the cal­i­bra­tors, then this will over-report the Blood Alco­hol Con­tent (BAC). The con­verse to this is true as well. If the tick marks for the cal­i­bra­tor and the unknown remain the same, but the base­line for the unknown is lower than the cal­i­bra­tor, it will over-report the BAC. The con­verse is true as well.

Auto-integration versus manual integration

Auto-integration ver­sus man­ual integration

Above is an exam­ple of how the auto-integration leads to less area and how the man­ual inte­gra­tion leads to more area. More area equates a higher BAC if this is per­formed on the EtOH peak.

What fur­ther com­pli­cates this is the use of the Inter­nal Stan­dard (ISTD). The inte­gra­tion events for the ISTD must also remain sta­tic. A peak is a peak is a peak. The same bound­ary marks apply. How­ever, with respect to the ISTD, the ISTD amount is inversely related to the EtOH. If there is too much ISTD cal­cu­lated, then the BAC will be ratio reduced. The con­verse is true as well.

How can you tell if any of this is done? Well, maybe you can and maybe you can’t as dis­cussed above and in the video. If you trust the lab­o­ra­tory, and if they report the base­line and the tick marks on all of the chro­matograms, you can sim­ply use a light­box or even hold it up to a light with the cal­i­bra­tors and the unknowns on top of one another and see if the bound­ary marks are all treated the same.

Bot­tom line take away: Con­sis­tent and appro­pri­ate inte­gra­tions are sci­en­tif­i­cally defen­si­ble. Incon­sis­tent or inap­pro­pri­ate inte­gra­tions are dif­fi­cult to defend. All QC, Ver­i­fiers and Unknowns must be treated in a con­sis­tent (same) man­ner and per a val­i­dated method. Oth­er­wise, you have a non-validated result.

The take away ques­tion: What does your lab­o­ra­tory do when it reports out it’s BAC?

Beer Born On Date
Beer Born On Date

Every­one wants to eat fresh food as opposed to stale food. No one wants to drink skunked beer. So, we have born-on dates on cer­tain foods and food­stuff. This allows us to judge whether or not we want to accept it and drink/eat it.

Car­rier gas purity is a big issue in Gas Chro­matog­ra­phy. We have to remem­ber that helium is the mobile phase that car­ries the ana­lytes that are going to be ana­lyzed. It pres­sur­izes the sys­tem to “push” the injected sam­ple through the col­umn. Ide­ally, the car­rier phase is totally inert which means that it does not inter­act with the sta­tion­ary phase or the ana­lytes of inter­est. We can’t have it inter­act with either so as to change the sam­ple or the result. Although helium is not the very best car­rier gas to use per the Van Deemter equa­tions, it has become more or less the dom­i­nant car­rier gas used in foren­sic test­ing lab­o­ra­to­ries when GC is used. Helium is typ­i­cally deliv­ered in a lab­o­ra­tory and stored in a cylinder.

Again, the car­rier gas must be totally inert which means that it does not inter­act with the sta­tion­ary phase or the ana­lytes of inter­est. For test­ing of VOC’s by GC-FID, helium meets this 2 cri­te­rion. It is totally inert which means that it does not inter­act with the sta­tion­ary phase or the ana­lytes of interest.

What if this were not so?

What if the car­rier gas is not pure and does not con­tain only helium but instead con­tains things that are not inert but con­tains things that inter­act with the sta­tion­ary phase or the ana­lytes of inter­est and are even detected?

The valid­ity of our results may be compromised.

This is a real problem.

Gas man­u­fac­tur­ers place out on the mar­ket for lab­o­ra­to­ries to buy dif­fer­ent purities.

  • high purity (99.998% min. purity)
  • ultra-high purity (99.999% min. purity)
  • research grade (99.9999% min. purity)

But are you in fact buy­ing that truly that level of pure gas?

Maybe not.

The gas man­u­fac­tur­ers mea­sure purity not as it is actu­ally con­tained in the cylin­der. It is mea­sured BEFORE it gets placed into the cylin­der. The man­u­fac­turer mea­sures for oxy­gen, mois­ture, total hydro­car­bons, car­bon monox­ide, nitro­gen, and oth­ers while it is being deliv­ered to the cylin­der. Again, no one at the man­u­fac­turer tests the purity after it is actu­ally placed in the cylinder.

Cus­tomers pur­chase the gas and rent the con­tainer (This is called “demurrage”).

There will always be some level of hydro­car­bons in the cylin­der as the gas is never ever 100% pure even when it is deliv­ered for the very first time.

Every time the cylin­der is emp­tied through use, it needs to be refilled. The gas com­pa­nies sim­ply hook the cylin­der up to a vac­uum and run the vac­uum through a cycle 3 times. Helium is very, very light, there­fore, it is first in time to be removed and is very easy to remove through the vac­uum. Hydro­car­bons are much heav­ier by com­par­i­son and there­fore will be the last in order to be removed and requires more vac­uum to remove. These three cycles is sim­ply not enough to remove all the hydro­car­bons. As this process of emp­ty­ing and fill­ing hap­pens over time with the incom­plete “drain­ing” (clear­ing) of hydro­car­bons each time, hydro­car­bons will build up in increas­ing con­cen­tra­tion over time. So, it is impor­tant to note the cylin­der “born on date” to gauge the poten­tial of increased hydro­car­bons over time in the cylin­der and there­fore intro­duced into the sam­ple that is going to be analyzed.

Hydro­car­bons will inter­act with the sam­ple and the sta­tion­ary phase. Remem­ber that a Flame Ion­iza­tion Detec­tor will burn all hydro­car­bons and there­fore detect it. There­fore, it is a poten­tial source for con­t­a­m­i­na­tion and cast doubt on the valid­ity of the reported result.

Cylinder Born on Date
Cylin­der Born on Date above is 07/07 or July of 2007
 

It’s been long known that the Hous­ton Crime Lab­o­ra­tory has strug­gled for a long time.

Huston Crime Laboratory DNA Section

Hus­ton Crime Lab­o­ra­tory DNA Section

Accord­ing to www.hpdlabinvestigation.org the rel­e­vant his­tor­i­cal con­text can be summed up as follows:

The pub­lic cri­sis that even­tu­ally led to the hir­ing of an inde­pen­dent inves­ti­ga­tor to review the Crime Lab’s oper­a­tions began on Novem­ber 11, 2002, with the first in a series of inves­tiga­tive news reports that aired on KHOU–Channel 11, a local Hous­ton tele­vi­sion sta­tion.  These tele­vi­sion news reports, which were reported to be the prod­uct of a three–month inves­ti­ga­tion per­formed by KHOU in con­sul­ta­tion with out­side foren­sics sci­en­tists, severely crit­i­cized the foren­sic analy­sis per­formed by the DNA/Serology Sec­tion of the Crime Lab in a num­ber of spe­cific cases.

Within a month of the air­ing of the first of these news reports, Act­ing Chief of Police Tim­o­thy Oettmeier com­mis­sioned an out­side review of the Crime Lab’s DNA/Serology Sec­tion.  Rep­re­sen­ta­tives from the Texas Depart­ment of Pub­lic Safety (“DPS”) Crime Lab Head­quar­ters and the Tar­rant County Med­ical Examiner’s Office per­formed an audit of the Crime Lab’s DNA/Serology sec­tion over the course of two days, Decem­ber 12 and 13, 2002.  On Decem­ber 18, 2002, based on the pre­lim­i­nary oral report of the audi­tors prior to the issuance of their final audit report, HPD sus­pended the per­for­mance of all DNA analy­sis by the Crime Lab.  The final report doc­u­ment­ing the audit’s find­ings was issued on Jan­u­ary 10, 2003.  DNA work by the Crime Lab has remained con­tin­u­ously sus­pended to this day, although HPD is hop­ing to re–open the DNA Sec­tion by the end of this cal­en­dar year.

In early 2003, HPD, in close con­sul­ta­tion with the Har­ris County Dis­trict Attorney’s Office, began a time–consuming process of iden­ti­fy­ing all cases in which some form of DNA analy­sis had been per­formed by the Crime Lab.  This process evolved into a long–term re-testing project coör­di­nated among HPD, the Har­ris County Dis­trict Attorney’s Office, and out­side DNA lab­o­ra­to­ries, which has iden­ti­fied for re-testing a total of 407 crim­i­nal cases involv­ing DNA analy­sis per­formed by the Crime Lab.

On or about Feb­ru­ary 21, 2003, Don­ald Krueger, the head of the Crime Lab, retired after serv­ing in that capac­ity for approx­i­mately eight years.  Fol­low­ing Mr. Krueger’s retire­ment, Robert Bobzean, a senior man­ager in the Crime Lab, took over lead­er­ship of the Lab on an interim basis.  In mid–July of that year, Frank Fitz­patrick of the Orange County (Cal­i­for­nia) Sheriff-Coroner’s Office was appointed Interim Direc­tor of the Crime Lab as part of a con­tract entered into by the City with the National Foren­sic Sci­ence Tech­nol­ogy Cen­ter (“NFSTC”), a non–profit entity whose mis­sion is “to pro­vide qual­ity sys­tems sup­port, train­ing and edu­ca­tion to the foren­sic sci­ence com­mu­nity in the United States.”  Dur­ing the course of its con­sul­ta­tion with the Crime Lab, the NFSTC pro­duced writ­ten eval­u­a­tions of var­i­ous aspects of the Crime Lab.  In Octo­ber 2003, ques­tions arose related to the per­for­mance of the Tox­i­col­ogy Sec­tion, which led to the sus­pen­sion that month of tox­i­co­log­i­cal analy­sis by the Crime Lab.  Also in Octo­ber 2003, Irma Rios was appointed to be the new per­ma­nent head of the Crime Lab.  Ms. Rios had been with the DPS crime lab­o­ra­tory sys­tem for over nine­teen years and was a mem­ber of the out­side audit team that reviewed the Crime Lab’s DNA/Serology Sec­tion in Decem­ber 2002.

The Inter­nal Affairs Divi­sion inves­ti­gated sev­eral Crime Lab cases for both crim­i­nal and admin­is­tra­tive vio­la­tions. As a result of the inves­ti­ga­tions, var­i­ous admin­is­tra­tive cites were sus­tained. Sev­eral super­vi­sors resigned in lieu of ter­mi­na­tion. Based on the sever­ity of the vio­la­tions, dis­ci­pline ranged from a writ­ten rep­ri­mand to 28 days of sus­pen­sion. All of the inter­nal affairs inves­ti­ga­tions were reviewed by the Dis­trict Attorney’s Office for crim­i­nal mis­con­duct. Two sep­a­rate Grand Juries reviewed the evi­dence in the crime lab inves­ti­ga­tions and no indict­ments were returned. (What a shocker!)

[Source: http://www.houstontx.gov/police/crimelab_faq.htm]

Now there is a new wrin­kle in the saga:

City Lead­ers Blast Houston’s Crime Lab

by: Lau­rie Johnson

Houston’s crime lab con­tin­ues to spark debate at City Hall. Coun­cilmem­bers ques­tioned why they should con­tinue to autho­rize con­tracts for the lab when the city intends to out­source its evi­dence to an inde­pen­dent lab in the future.

The Hous­ton Police Department’s belea­guered crime lab took more crit­i­cism from a few city coun­cilmem­bers as they chal­lenged a five year con­tract to pur­chase DNA kits for HPD, another con­tract to ana­lyze the crime lab’s back­log of rape kits stored on site for years and a con­tract for fin­ger­print analysis.

This is Coun­cilmem­ber C.O. Brad­ford, who was once HPD’s police chief.

“For years now, I’ve been ask­ing, and a year and a half as a coun­cilmem­ber, where is the long range plan for the crime lab? What are we going to do to resolve the out­stand­ing issues asso­ci­ated with the Hous­ton Police Depart­ment or crime lab. And it’s fair to say that my expe­ri­ence, my back­ground and my involve­ment with some of the past issues in the crime lab put me in a unique posi­tion to stand pub­licly and say that we need a plan.”

Brad­ford says police chiefs are not sci­en­tists and are not qual­i­fied to over­see crime lab operations.

“There­fore, we need to move aggres­sively, in my view, to remove the crime lab and its asso­ci­ated activ­i­ties to an inde­pen­dent entity out­side the scope of the Hous­ton Police Depart­ment, because we really do need super­vi­sion and over­sight from per­son­nel that are sci­en­tists and have the proper back­ground to over­see what’s going on with the analysis.”

Hous­ton Mayor Annise Parker says she agrees that the city shouldn’t be oper­at­ing its own crime lab. She sup­ports the idea of an inde­pen­dent regional lab that would pro­vide ser­vices for the city and Har­ris County along with other area municipalities.

“One of the dif­fi­cul­ties we have is we don’t have any money — any spare money. The county really doesn’t either. We believe that it’s only appro­pri­ate to have an inde­pen­dent crime lab. And I think the pref­er­ence at the county is for them to con­trol the crime lab and they’d like us to brings ours under them.”

Coun­cilmem­ber Jolanda Jones also voiced her con­cerns about the city’s lack of a plan. Jones, who is an attor­ney, dealt with crime lab issues back in 2002 on one of her legal cases and says she’s tired of still talk­ing about it.

“I will tell you to this day in every dis­ci­pline at the crime lab, col­lec­tion of evi­dence is prob­lem­atic. But we are try­ing to pre­tend like the crime lab is okay.”

The coun­cil approved the three con­tracts for crime lab ser­vices, although Coun­cilmem­bers Jones, Brad­ford and Mike Sul­li­van voted against the fin­ger­print contract.

Here! Here! to Coun­cilmem­ber Brad­ford when he says the truth: “police chiefs are not sci­en­tists and are not qual­i­fied to over­see crime lab oper­a­tions” and that sci­en­tists should over­see the sci­ence and the admin­is­tra­tion of the laboratory.

C.O. Bradford

Coun­cilmem­ber C.O. Bradford

 
Lions and Tigers and Bears... Verifiers, Calibrators and Controls... Oh my!
Lions and Tigers and Bears… Ver­i­fiers, Cal­i­bra­tors and Con­trols… Oh my!

Some­times a crim­i­nal defense attor­ney can at times feel like Dorothy in the Wiz­ard of Oz in that we are trans­ported from the rel­a­tive safety of home (the court­room) to the weird world of Oz (the lab­o­ra­tory). There are unusual and often times con­flict­ing phrases and words that seem to defy com­mon sense. Some­times, words and phrases are used inter­change­ably and with lit­tle appar­ent dis­tinc­tion. In this post we will exam­ine a decon­vo­lute some of these impor­tant terms.

Qual­ity Con­trol- We cov­ered the con­cept of Qual­ity Con­trol (QC) before. QC is strictly speak­ing a process that is used to con­struct the cal­i­bra­tion curve that our knowns are tested and then an unknowns are tested against. This is typ­i­cally per­formed in the begin­ning of the run.

Standards/Controls- is a ref­er­ence solu­tion or test solu­tion used for assess­ment of the per­for­mance of an ana­lyt­i­cal pro­ce­dure. A rig­or­ously tested and high qual­ity known ana­lyte at a cer­tain con­cen­tra­tion is known as a Cer­ti­fied Ref­er­ence Mate­r­ial (CRM). CRMs are gen­er­ally gov­erned by ISO Guide 34:2009. NIST makes its own ser­vice marked brand of CRMs named Stan­dard Ref­er­ence Mate­ri­als (SRMs). CRMs and SRMs should have state­ments of cal­i­bra­tion (pre­ci­sion) and boas (accuracy).

Cal­i­bra­tor- Often it is in the begin­ning of a run. What makes a stan­dard or con­trol a cal­i­bra­tor is that it is placed before the unknowns are tested. The cal­i­bra­tors are run in a series over the hoped for lin­ear dynamic range. The response from the test­ing of the cal­i­bra­tors is plot­ted on a sig­nal ver­sus con­cen­tra­tion y-x axis graph. A line is drawn along the data points with the R2 cal­cu­lated to deter­mine if the response is lin­ear. Cal­i­bra­tors are used to con­struct the cal­i­bra­tion curve. It is the QC of a quan­ti­ta­tive process. A cal­i­bra­tor is a solu­tion hope­fully from a trace­able source and hope­fully a CRM/SRM with a known amount (con­cen­tra­tion) of ana­lyte of inter­est that is hope­fully pure and only con­tains that ana­lyte of inter­est. It is placed within the batch of the run as part of the QC pro­ce­dures to insure that the ana­lyt­i­cal instru­ment is detect­ing the known within an estab­lished stated and often times arbi­trary range of values.

Ver­i­fier- Often it is in the mid­dle of a run or at an end of the run. What makes a stan­dard or con­trol a ver­i­fier is that it is placed among the unknowns are tested after the run. It too con­tains a known ana­lyte at a known con­cen­tra­tion. It is placed within or at the end of the run to insure that the ana­lyt­i­cal instru­ment is detect­ing the known within an estab­lished tol­er­ance through­out the test­ing of unknowns. Think of it as a check. If the test­ing method has a scheme where the lab­o­ra­tory places a ver­i­fier amongst the unknowns tested, then this is not a func­tion of qual­ity con­trol, but rather an act of verification.

There is a big dif­fer­ence. QC data (where a series of cal­i­bra­tors are used over a range of con­cen­traions) is used to estab­lish a cal­i­bra­tion curve. The data is inputted and R2 value is cal­cu­lated and then the data adjusted to make it fit. Ver­i­fi­ca­tion data sim­ply tests at one point on the cal­i­bra­tion curve already estab­lished, that data is then eval­u­ated by a human, not a machine, and no adjust­ment is made to cor­rect for bias if the ver­i­fier data result does not per­fectly fit against the cal­i­bra­tion curve expected result. The cal­i­bra­tion curve is not altered based upon this new data point. Test­ing con­tin­ues if the ver­i­fi­ca­tion data is within an arbi­trary range. Again, even if the ver­i­fi­ca­tion data shows appre­cia­ble bias, noth­ing is done about it. Unfor­tu­nately, a lot of crim­i­nal lab­o­ra­to­ries in an effort to save money (which really is not that much) make their own in-house ver­i­fier solu­tions. I call this home brew or lab­o­ra­tory moon-shining. The dif­fi­culty with mak­ing it on your own is two fold: (1) You may make it wrong (impu­ri­ties or impre­cise or inac­cu­rate con­cen­tra­tion lev­els), and (2)it’s like the fox guard­ing the hen house in that you are trust­ing the lab­o­ra­tory to guard itself.

Home brew is not a good idea

Home brew is not a good idea

You must under­stand the dif­fer­ence between cal­i­bra­tors and verifiers.

 

There is a large dif­fer­ence between a sin­gle col­umn analy­sis and a dual col­umn analy­sis when it comes to the abil­ity to most cor­rectly iden­tify and quan­ti­tate an unknown in the sci­en­tific world.

In foren­sic sci­ence, we are con­stantly test­ing unknowns. What is meant by this is that we have a sam­ple that is seized from a crime scene or from a per­son, but we don’t know what it con­tains. For exam­ple, in blood analy­sis for EtOH in an alleged DUI case, we have a sam­ple of blood that is taken from the accused, but just by look­ing at it, we can­not know if there is even ethanol in it, and even if present, how much there is. We need to ana­lyze it using instru­men­ta­tion in a sci­en­tific manner.

We can't tell if there is EtOH in this sample just by looking at it
We can’t tell if there is EtOH in this sam­ple just by look­ing at it

When we are look­ing to be sci­en­tific about our analy­sis we are look­ing to be as spe­cific as pos­si­ble, and try­ing not to be merely selec­tive. There is a large and impor­tant sci­en­tific dif­fer­ence between being selec­tive and spe­cific. As we wrote before on this blog: Metrol­ogy in Quan­ta­tive Mea­sure: Is it Spe­cific or Selec­tive or Neither…

The Inter­na­tional Union of Pure and Applied Chem­istry (IUPAC), which is the world author­ity on chem­i­cal nomen­cla­ture, ter­mi­nol­ogy, stan­dard­ized meth­ods for mea­sure­ment, atomic weights and other crit­i­cally eval­u­ated data and oth­ers have defined the dif­fer­ence between these often con­fused terms as follows:

A spe­cific reac­tion or test is one that occurs only with the sub­stance of inter­est, while a selec­tive reac­tion or test is one that can occur with other sub­stances but exhibits a degree of pref­er­ence for the sub­stance of inter­est.  Few reac­tions are spe­cific, but many “exhibit selectivity”.

Other com­mon def­i­n­i­tions include:

Selec­tiv­ity gives an indi­ca­tion of how strongly the result is affected by other com­po­nents in the sample.

and also

Selec­tiv­ity refers to the extent to which the method can be used to deter­mine par­tic­u­lar ana­lytes in mix­tures or matri­ces with­out inter­fer­ences from other com­po­nents of sim­i­lar behavior.

A selec­tive test may be not a spe­cific test due to cross-reactivity, inter­fer­ence, or codetermination.

So, we search for he most spe­cific form of analy­sis. In the world of DUI for EtOH, the gov­ern­ment typ­i­cally set­tles for Head­space gas Chro­matog­ra­phy with Flame Ion­iza­tion Detec­tor (HS-GC-FID). GC-FID is not the most spe­cific test avail­able for EtOH exam­i­na­tion as there is Gas Chro­matog­ra­phy with Mass Spec­trom­e­try (GC-MS) for exam­ple which is much more selec­tive and bor­ders on spe­cific when it comes to EtOH analy­sis, but for what­ever pol­icy rea­son, the gov­ern­ment chooses not to do the most scein­tific thing which is to use the most spe­cific assay avail­able. There is no sci­en­tific rea­son not to test for EtOH on the most spe­cific assay avail­able. In fact, it could be legit­i­mately argued that rely­ing on GC-FID instead of GC-MS for EtOH deter­mi­na­tion and quan­tifi­ca­tion is not sci­en­tific as GC-MS exists and is read­ily avail­able. How­ever, that is a post for another day.

As we are seemly inex­plic­a­bly stuck with the sci­en­tific step-sister of analy­sis in GC-FID as opposed to GC-MS, we must look at ways that the gov­ern­ment chooses to employ GC-FID to see whether or not as an assay it is valid. As our last series of posts “Method Val­i­da­tion for Lawyers” revealed, there is power in the words “valid” and “valid­ity.” With­out hav­ing a truly valid method that has been proven to be suit­able for its intended pur­pose, we can­not have a valid result.

Some foren­sic lab­o­ra­to­ries choose to use a con­fig­u­ra­tion in GC-FID that is known as a sin­gle col­umn, sin­gle injec­tion setup. In this set up there is one installed col­umn and the ana­lyst makes one injec­tion (or the autosam­pler does) to test the sample.

An installed single column GC-FID setup
An installed sin­gle col­umn GC-FID setup

With­out any sci­en­tific doubt, a sin­gle col­umn method of analy­sis is not foren­si­cally or sci­en­tif­i­cally defen­si­ble or acceptable.

Remem­ber that when we use GC-FID, we can never achieve true speci­ficity, the most we can hope for is the pos­si­bil­ity of being merely selec­tive as demon­strated and proven through the res­o­lu­tion stan­dard (sep­a­ra­tion matrix/standard mix). The qual­i­ta­tive result is only based upon one cri­te­ria which is the reten­tion time. Reten­tion times through any given col­umn are not unique to one spe­cific volatile organic com­pound (VOC) to the exclu­sion of every thing else in the uni­verse. Hence, we have the often repeated phrase that all legit­i­mate tech­ni­cally trained chro­matog­ra­phers know and can recite in their sleep—the lim­i­ta­tion of GC-FID is that the reten­tion time is merely char­ac­ter­is­tic of a com­pound and cer­tainly not adju­dica­tive or con­fir­ma­tory of the speci­ficity of that com­pound— mean­ing a peak at a given reten­tion time is not a unique qual­i­ta­tive mea­sure (to the exclu­sion of every other com­pound in the universe).

Don’t take just my word for it con­sider the following:

As ven­er­ated Pro­fes­sor Harold McNair, PhD writes in his book, Basic Gas Chro­matog­ra­phy,

Reten­tion times are char­ac­ter­is­tic of a GC sys­tem, but they are not unique, so GC reten­tion times can­not be used for qual­i­ta­tive confirmation.

He fur­ther writes:

Iden­ti­fi­ca­tion of an unknown by com­par­i­son to reten­tion times using stan­dards that forms the basis of the qual­i­ta­tive analy­sis [in GC-FID analysis].

He con­cludes:

Unfor­tu­nately, GC sys­tems can­not con­firm the iden­tity or struc­ture of any peak. Reten­tion times are related to par­ti­tion coef­fi­cients (Chap­ter 3); and while they are char­ac­ter­is­tic of a well-defined sys­tem, they are not unique.

How do we acknowl­edge this lim­i­ta­tion in the lack of speci­ficity and try to mit­i­gate it?

We can add a dif­fer­ent col­umn and ana­lyze the sam­ple con­cur­rently on both columns. As we learned in our post What is a Gas Chro­matog­ra­phy col­umn and why should I care?, the col­umn, if prop­erly selected and prop­erly installed, is what pri­mar­ily causes the sep­a­ra­tion of the var­i­ous VOCs to occur. What we do is select two dif­fer­ent columns with two dif­fer­ent sta­tion­ary phases. We attach a y-splitter that will take the sin­gle injec­tion made into the injec­tor port and divide the sam­ple into two dif­fer­ent path­ways with one part of the sam­ple going to one col­umn for analy­sis and the sec­ond part going to another col­umn for analysis.

A y-splitter
A y-splitter splits the same sam­ple injec­tion and sends the parts to two dif­fer­ent columns for analysis

The strength of a well-designed dual col­umn analy­sis method where the sta­tion­ary phase is dif­fer­ent between the two columns is that this dif­fer­ence in the sta­tion­ary phase will cause dif­fer­ent sep­a­ra­tion of the ana­lytes (both in terms of reten­tion time and pos­si­bly even elut­ing order) as proven by the chro­matograms of the analy­sis of the res­o­lu­tion stan­dard (sep­a­ra­tion matrix/standard mix). This dif­fer­ent elut­ing order and dif­fer­ent reten­tion times only min­i­mizes, but does not entirely elim­i­nate the pos­si­bil­ity of co-elution as again, the resolv­ing (sep­a­rat­ing) power of the method is only deter­mined by one non-unique mea­sure which is the two reten­tion times. Even though there is a change in the elut­ing order poten­tially and the reten­tion times are dif­fer­ent based upon the sta­tion­ary phase com­po­si­tion, again, it must be empha­sized that the basic lim­i­ta­tion of GC-FID remains in that a reten­tion time is merely char­ac­ter­is­tic of the ana­lyte, but is cer­tainly not confirmatory.

A schematic of a dual column GC-FID. Note the change in the eluting order and retention time among the columns
A schematic of a dual col­umn GC-FID. Note the change in the elut­ing order and reten­tion time among the columns

This is why dual col­umn is referred to as the poor man’s Mass Spec as it has a more orthog­o­nal approach towards the qual­i­ta­tive mea­sure than does a sin­gle column.

How the cur­rent trend of the crime lab­o­ra­tory using a dual col­umn GC-FID is alarm­ingly unscientific.

What is most alarm­ing to me is the trend that is devel­op­ing across the United States where the sec­ond col­umn is not being used for quan­tifi­ca­tion at all. In this trend that I see sweep­ing all across the US, the sec­ond col­umn is merely being used as a “con­fir­ma­tory” col­umn in that if the reten­tion time matches with the standards/controls in the Qual­ity Con­trol sam­ples, then it is pre­sented as “ver­i­fied” in terms of the qual­i­ta­tive mea­sure by sim­ply that sec­ond col­umn match­ing reten­tion time with the knowns that act as the standards/controls. As we explain above, that is a dan­ger­ous and unsci­en­tific approach.

Installed dual column GC-FID

Installed dual col­umn GC-FID

The rea­son that this is so impor­tant given the above con­text (there are other rea­sons that it is alarm­ing, but I want to stick to this ref­er­ence) is that with­out the sec­ond col­umn giv­ing a quan­ti­ta­tive mea­sure, we can­not fairly elim­i­nate co-elution (where two com­pounds elute at the same time, but only get iden­ti­fied and quan­ti­tated as one com­pound) because if the sec­ond col­umn is used to also quan­tify it will serve as an indi­rect deter­mi­na­tion of whether or not there is co-elution. If the sec­ond col­umn also pro­vides a quan­tifi­ca­tion of the unknown, we would exam­ine the pre­ci­sion of the quan­ti­ta­tive results (how closely the num­bers agree among those given by col­umn A and those of col­umn B– do the A’s match the B’s?). If there is co-elution that was “dis­cov­ered” by the dual col­umn approach, then we would expect to see impre­ci­sion between these num­bers (the A’s don’t match the B’s).

Now that they have decided as an orga­ni­za­tion to not quan­ti­tate on the sec­ond col­umn, we have lost a vital part of qual­ity con­trol and the lab super­vi­sor has lost a pow­er­ful tool of qual­ity assur­ance. It is just bad science.

Fur­ther, there is no legit­i­mate sci­en­tific rea­son for quan­ti­at­ing on the sec­ond col­umn. If you are doing good qual­ity work ad your meth­ods and instru­ments are in con­trol, then your num­bers should agree.

It’s not a time thing.

As it is a sin­gle injec­tion y-splitter dual col­umn analy­sis any­way, the amount of time it takes to make a cal­i­bra­tion curve, eval­u­ate it and then incor­po­rate it into the soft­ware for one col­umn is vir­tu­ally the same amount of time to do the same on col­umn 2. There is vir­tu­ally no added time. It makes no sense from a sci­ence point-of-view.

So in con­clu­sion, we can fairly con­clude the following:

  • Sci­en­tif­i­cally, we always want to test our unknowns on the most spe­cific assay available.
  • GC-FID is not the most spe­cific assay available.
  • Lab­o­ra­to­ries that use sin­gle col­umn GC-FID as their method of analy­sis do not pro­duce foren­si­cally or sci­en­tif­i­cally defen­si­ble or accept­able results.
  • Lab­o­ra­to­ries who use dual col­umn GC-FID that do not quan­ti­tate on both their columns do not pro­duce foren­si­cally or sci­en­tif­i­cally defen­si­ble or accept­able results.
  • Good sci­ence is not always prac­ticed in the mod­ern state crime laboratory.
 

As I have writ­ten before a lot of foren­sic sci­ence is really legit­i­mate ana­lyt­i­cal chem­istry that is re-purposed for the court­room, but with­out proper sci­en­tific method val­i­da­tion before deploy­ing it into this new pur­pose. This re-purposing of legit­i­mate tech­niques and employ­ing them with­out exam­in­ing the true valid­ity of doing so is not sci­en­tific. I call this police sci­ence, not true sci­ence. It is sci­ence fiction.

It is the dif­fer­ence between data-driven deci­sions ver­sus data dri­ving the decisions.

The prob­lem with this approach is that the valid­ity of the tech­nique is doubt­ful when­ever we do so. In fact, when we do so we truly have a non-validated result. When we look at the data, the valid­ity of the re-purposed is com­pro­mised and in the worst cases is truly invalid.

What I am about to do is to show you some data. This data comes from the col­umn man­u­fac­tur­ers them­selves. It is their pub­lished data and chro­matograms from their best equip­ment and by their tech­ni­cal experts run­ning the instru­ments. They put the infor­ma­tion on their web­sites, in their trade mag­a­zines, and in their sales cat­a­logs. It is their most beau­ti­ful work. So, in other shorter words: This is as good as it gets. Like most things in life, when applied in prac­tice in the real world out­side of the man­u­fac­turer, the opti­mal that these chro­matograms rep­re­sent are not repli­cated in the crime lab­o­ra­tory. Fre­quently, the chro­matog­ra­phy is worse.

Before we review the data, let’s brush up on some of our fundamentals.

In our post What is a Gas Chro­matog­ra­phy col­umn and why should I care?, we learned that the col­umn is the main dri­ving force of our chro­mato­graphic goal which is to sep­a­rate, cre­ate speci­ficity and make for a unique qual­i­ta­tive mea­sure that answers the ques­tion of “What do we have to the exclu­sion of every­thing else in the uni­verse?” We also know that with­out proper sep­a­ra­tion (res­o­lu­tion), then we can­not pro­vide legit­i­mately for a valid quan­ti­ta­tive result which seeks to answer our ques­tion: “Of what we were able to sep­a­rate (or not) how much do we have?” Finally, we learned in our post Mass Spec­troscopy for Lawyers Part 8: A sci­en­tific war, between spec­tro­scopists and chro­matog­ra­phers is co-eution a prob­lem in hyphen­ated MS work? that co-elution and the lack of proper sep­a­ra­tion (res­o­lu­tion) in Mass Spec­trom­e­try invites in ques­tions of human integrity and the chance of incor­rect inter­pre­ta­tion (judg­ment calls) that can result in the wrong qual­i­ta­tive result.

We have a non-colloidal mix­ture of a whole bunch of stuff. It is injected into the machine. Based upon the chem­i­cals in the coat­ing of the inner wall of the col­umn (called the sta­tion­ary phase), it will attract dif­fer­ent com­pounds dif­fer­ently and “hold them up” as they travel along the length of the col­umn. Put more sim­ply, if you select the right sta­tion­ary phase, dif­fer­ent com­pounds in the non-colloidal mix “hang around” longer than oth­ers in the col­umn. Depend­ing upon the sta­tion­ary phase we chose to use, we can cause the sep­a­ra­tion of the dif­fer­ent com­pounds. Dif­fer­ent sta­tion­ary phase, we get dif­fer­ent sep­a­ra­tion either mea­sured in time or even in order of what comes out and when. There is no such thing as a uni­ver­sal “I sep­a­rate every­thing” col­umn for the very rea­son we have pointed out before—namely there are so many dif­fer­ent com­pounds (65 mil­lion reg­is­tered in CAS). Sep­a­ra­tion in the sta­tion­ary phase is based pri­mar­ily upon boil­ing point and polarity.

So what the police do is they re-purpose a col­umn from another appli­ca­tion (DB5 col­umn which is the most uni­ver­sal col­umn used in indus­try– 5%-Phenyl-methylpolysiloxane), stick a new title on it with­out doing any­thing more to improve it (EVDX-5MS), shoot cer­ti­fied ref­er­ence mate­ri­als through in a res­o­lu­tion matrix and get the fol­low­ing type of separation.

The Commandments of Chromatography

The Com­mand­ments of Chromatography

So, now with that refresher/reminder in place, we can look at data.

Notice how all of the peaks are not well resolved

Notice how all of the peaks (4.5) are not well resolved

 

Agilent publishes these as the purposes for this one column

Agi­lent pub­lishes these as the pur­poses for this one col­umn DB-35ms

 

The underlying manufacturer's chromatogram of this re-purposed column shows poor chromatography

The under­ly­ing manufacturer’s chro­matogram of this re-purposed col­umn (DB-35ms) shows poor chromatography

 

poor resolution again

Poor res­o­lu­tion again

Very poor resolution

Very poor resolution

 

I am fond of point­ing out that a Gas Chro­mato­graph (GC) and a Liq­uid Chro­mato­graph (LC) are not like a sim­ple cal­cu­la­tor where any­one walk­ing up to a cal­cu­la­tor regard­less if it is a 2 year old or a PhD in math­e­mat­ics who keys in 2+2, the result will always be 4, it requires inter­pre­ta­tion and elu­ci­da­tion. The machine has to be taught what the tar­get ana­lyte is (e.g., ethanol) and most impor­tantly what it is not by using a res­o­lu­tion standard/separation matrix. It also has to be taught how much there is through the process of cal­i­bra­tion. Out of the box from the ven­dor, the GC or LC knows noth­ing. In other words, the process is fun­gi­ble and sub­jec­tive. It is a human process and there­fore open to the whims of human integrity.

Here is a part of the Agi­lent web­site that proves this very point. It really speaks to the point that the raw data com­ing from the chro­mato­graph must be manip­u­lated in order to get an answer:

Agilent software screen capture

Agi­lent soft­ware screen capture

The above screen­shot comes from Agilent’s web­site and it reads:

In today’s ana­lyt­i­cal research and qual­ity con­trol labs, ana­lysts con­trol their chro­mato­graphic instru­men­ta­tion with Chro­matog­ra­phy Data Sys­tems (CDS) Soft­ware. With ana­lysts now spend­ing more time review­ing, re-analyzing and manip­u­lat­ing their data, soft­ware has become a key tool in the ana­lyt­i­cal lab­o­ra­tory. Open­LAB CDS offers you intu­itive oper­a­tion and admin­is­tra­tion, automa­tion of rou­tine tasks and advanced report­ing with built-in export func­tions to MS Excel and Adobe PDF for­mats and will reduce ana­lyt­i­cal errors with supe­rior instru­ment con­trol for Agi­lent and 3rd party instru­ments – reduc­ing the time your ana­lysts spend on soft­ware and giv­ing them more time to run samples.

So I renew again my call for those lab­o­ra­to­ries that engage in test­ing and cal­i­bra­tion pro­vide the raw com­puter data.