Simply put, the column is where the chromatographic magic occurs. It is how the complex mixture of the jumbled mess of “stuff” (for example, blood) is uniquely separated into its unique parts (hopefully if everything is done correctly). The variables of the column in conjunction with the conditions of the method are that which causes […]
Can (insert analyte) be tested for by GC-FID or GC-MS?
One of the most frequent questions that I get from other lawyers is something like this: Can synthetic marijuana be tested for by GC-FID or GC-MS? Can marijuana be tested for by GC-FID or GC-MS? Can methamphetamine be tested for by GC-FID or GC-MS? The truthful answer is, it depends. Let’s take for example the […]
Passive marijuana smoke leads to positive test that is misinterpreted as a probation/parole violation or being DUID
It is one thing to have a result. It is a whole other thing to know what to do with it. This blog post will consider the case of positive test results and the limits of interpreting the significance of those results in various contexts. It is estimated that as of 2009, one out of […]
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 case for raw data: “Integration” in Gas Chromatography: How to make an innocent person guilty in a DUI case by manipulating the software. The video below is part of the lecture that I gave at the hands-on laboratory training course held by the American Chemical Society (ACS) and Axion Analytical Labs in Chicago, IL […]
What’s Salt Got to Do With It? Salting Out Effect
If Tina Turner was an inexperienced chromatographer, perhaps she would sing “What’s salt got to do with it?” One of the important aspects of forensic testing is the validity of the result. The validity of the result is comprised of assuring that a test result is: Precise-a measure of how closely the results can be […]
Mass Spectrometry is only computer assisted pattern recognition
In our prior post, CRMs: Reference materials and standards, we saw how the library is important in analytical chemistry. It enables the analyst to compare the unknown to a known to arrive at an opinion that is often expressed as a conclusion. We saw that there are many different commercial sources for these libraries. In […]
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