Boss Tweed (pictured below) was a notorious political crime boss in New York. He had a quote that was attributed to him: “Remember the first rule of politics. The ballots don’t make the results, the counters make the results. The counters – keep counting.”
This is also true in chromatography.
We have written in this blog about how receiving printed chromatograms in criminal cases is only the beginning of an attorney’s exercise of due diligence:
- The case for raw data: “Integration” in Gas Chromatography: How to make an innocent person guilty in a DUI case by manipulating the software
The qualitative and quantitative measurement of ethanol by way of Gas Chromatography with Flame Ionization Detector (GC-FID) is a process that involving the recording of an analog signal (the flame) that is then converted and captured to a digital form (the electronic data files). The electronic data files are immediately generated and recorded in the machine in a designated file folder whenever analysis is made. There is no way to “abort” or not record the results. The electronic data files are locked in their native format and are not subject to manipulation. It is solely and exclusively based upon this locked data that the electronic data files are then used to produce a printed record of the measurement known as a chromatogram.
Based upon the programming of the software, the electronic data files interpret, label and encode the chromatogram with information such as which peaks to show, and the qualitative identification of the peak as well as the quantitative measurement.
This type of programming of generally called integration as pictured below:
The operator or analyst of the machine can change the parameters of the integration in such a way that it may not be discoverable if simply the printed chromatogram is provided. The integration can only be verified and truly discovered by examining the electronic data files. The consistency of the integration between calibrators and unknowns can only be verified by examining the electronic data files. The parameters of the peak, which is controlled by the programming of the software, controls this encoded information in the printed chromatogram. In addition, area reject heights can be set to ignore and hide peaks.
Don’t believe me? See the below.