It is true. They say beauty is in the eye of the beholder. Every year they have the world’s ugliest dog contest where invariably the reporters report on this event and blast the picture of the world’s ugliest dog all over the internet. Invariably comments come from all across the world that the dog isn’t…
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How do they make the squiggly lines turn into a magic number: Area under the peak
One of the aspects of my job that I really enjoy is explaining the science of Blood Alcohol Concentration and/or reported levels of Drugs of Abuse to normal everyday folks, judges, jurors, prosecutors and even fellow attorneys. One of the most common questions I get asked is in the area of gas chromatography. Just yesterday…
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Carryover effect part 3: Flushing of inert gas is not enough to prove there is no carryover
We have all heard of the "three second rule". Namely that if someone drops food on the floor that it is good and safe to eat if you are above to snatch it back up within three seconds. Sometimes we blow on it even to "get off the bacteria, germs and other stuff from the…
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Internal standard the likely culprit for inaccurate BAC results
OK so you followed our recent series on the Carry-Over Effect problem that can lead to inaccurate Blood Alcohol Content results in the posts: A large problem in Gas Chromatography: No uniform standard for GC run position or composition The Carry-over Effect: Lack of Blanks between tests leads to false positive or inflated BAC results…
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Carryover effect part Deux: Autodilution may be part of the problem for false blood results in DUI
Just recently I posted "The Carry-over Effect: Lack of Blanks between tests leads to false positive or inflated BAC results" where we discussed the carry-over effect in Blood testing in DUI cases. One of the possible places for carry-over effect is when an auto-pipetter is used in an autodiluter. Pennsylvania has some labs that in their…
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Personal bias is bad, but analytical bias spells disaster in DUI BAC and Drugs of Abuse testing
All analytical devices are subject to analytical drift. Analytical drift occurs during as a result of just good old fashioned use or over time even with a lack of use. As the machine is used time and time again, it will become less precise and/or less accurate. Accuracy is characterized by large standard deviation with…
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In analytical chemistry for ETOH and Drugs of Abuse determination, it is very true that the matrix is all around us but truly is ignored
Keanu Reeves in the movie The Matrix noted that the matrix is all around us, you just haven’t chosen to see it. He had no idea that his statement would hold true in analytical testing for ETOH and drugs of abuse testing in DUI prosecution as well. The matrix is the substrate form which we…
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The variables of the Gas Chromatography process
I have posted before on Gas Chromatography and its principles. Gas Chromatography and why is it is so important to Pennsylvania DUI arrests Crimping a Headspace Vial in Gas Chromatography: How not putting the "lid on the jar" can lead to disaster in a DUI case A large problem in Gas Chromatography: No uniform standard…
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If he was an analytical chemist or a DUI defense attorney he would say “Show me the separation!!”
Who can forget Cuba Gooding Junior in the movie Jerry McGuire shouting “SHOW ME THE MONEY!”??? If he was an analytical chemist or a DUI defense attorney facing a purported result from a Headspace Gas Chromatograph with a Flame Ionization Detector, he would yell: “SHOW ME THE SEPARATION!!!!!!” Well, that is one of the things that a…
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The Carryover Effect: Lack of Blanks between tests leads to false positive or inflated BAC results
Imagine. You go into your doctor’s office for a routine physical. As part of that routine physical, the doctor takes your blood. You come back two weeks later where the doctor delivers the single worst sentence you have ever heard in your life: “I’m sorry but you have cancer.” Then comes ever worse news from…
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