Guest Blog Post From Dr. Frederic Whitehurst PhD JD: Of moos and clucks-the myth of FTIR identification

Guest Blog Post From Dr. Frederic Whitehurst PhD JD: Of moos and clucks-the myth of FTIR identification

On March 8, 2012, in Chemistry, Contextual Bias, Equipment, Ethics, Ethics: Scientist, Identification, In The Courtroom, Infrared Spectroscopy, Solid Drug Dose, by Justin J. McShane

Of moos and clucks-the myth of FTIR identification By:  Frederic Whitehurst, J.D., Ph.D. [1] OK, so we will now discuss moos and clucks. Which is the basis for the problem with Fourier Transform Infrared Spectroscopy (FTIR) in forensic science. [2] If you close your eyes in a stock yard you can’t tell what moo came […]

Zero is not a valid data point for calibration purposes

Zero is not a valid data point for calibration purposes

On March 6, 2012, in Chemistry, Equipment, Ethics, Ethics: Scientist, Identification, In The Courtroom, Laboratory Procedure, Metrology, by Justin J. McShane

When the quantitative measurement really matters to determine guilt, we have to understand how that measurement is achieved. In the case of the analysis of biological samples that are tested, quantitation of an unknown is derived from a calibration curve. The proper construction of the calibration curve is a crucial component of quality control. It […]

Guest Blog Post From Dr. Frederic Whitehurst PhD JD: Circuitous thought-the myth of reliable and valid marijuana identification in the courtroom

Guest Blog Post From Dr. Frederic Whitehurst PhD JD: Circuitous thought-the myth of reliable and valid marijuana identification in the courtroom

On March 1, 2012, in Chemistry, Contextual Bias, Equipment, Ethics, Ethics: Scientist, Identification, In The Courtroom, Solid Drug Dose, by Justin J. McShane

Circuitous thought-the myth of reliable and valid marijuana identification in the courtroom By:  Frederic Whitehurst, J.D., Ph.D. [1] As scientists we all agree that the hallmarks of science are validity and reliability. What do we mean by that? Well, the government scientist has to agree that his method of answering a question put to him […]

Why not stipulate to a forensic science result?

Why not stipulate to a forensic science result?

On February 14, 2012, in Chemistry, Contextual Bias, Equipment, Ethics, Ethics: Lawyer, General Information, In The Courtroom, by Justin J. McShane

I was recently asked a question which is basically this: “Justin, why don’t you stipulate to any forensic science result ever?” My answer is simple. I haven’t found a single analytical test or a single forensic science result that does not have some area of legitimate inquiry whether it is in the data (the test […]

Quality Control in GC-FID: Teaching the machine right from wrong

Quality Control in GC-FID: Teaching the machine right from wrong

On February 7, 2012, in Chemistry, Equipment, Ethics, Ethics: Scientist, GC-FID & GC/MS, Identification, In The Courtroom, Laboratory Procedure, Metrology, Standards, by Justin J. McShane

It is shocking but very true statement that most sophisticated instruments such as a Gas Chromatograph (GC) with various detectors whether it is a mass spectrometer (MS) or flame ionization detector (FID) when produced and manufactured are incapable of producing meaningful results “straight out of the box.” These machines have to be “taught” what it […]

The myth of specific identification of Marijuana in criminal court Part 7: Is there a better way to test for marijuana?

The myth of specific identification of Marijuana in criminal court Part 7: Is there a better way to test for marijuana?

On January 31, 2012, in Chemistry, Equipment, Ethics, Ethics: Scientist, Identification, In The Courtroom, Solid Drug Dose, by Justin J. McShane

Throughout this series of posts we have examined the Thorton-Nakumura protocol that is used throughout the United States for the prosecution of illegal possession marijuana. A fair examination of the question reveals that there is no validity to the notion that the 3 test regimen produces a valid conclusion that the unknown examined in fact […]

The myth of specific identification of Marijuana in criminal court Part 5: What is Thin Layer Chromatography? Is it a “good” test?

The myth of specific identification of Marijuana in criminal court Part 5: What is Thin Layer Chromatography? Is it a “good” test?

On January 24, 2012, in Chemistry, Equipment, Identification, Solid Drug Dose, by Justin J. McShane

All prosecutions for the unlawful possession of marijuana requires as an essential element of the crime for the government to advance proof that the unknown submitted for testing is in fact marijuana (contains THC). Can the government actually do that based upon its typical testing method? In this series of posts we are going to […]

The myth of specific identification of Marijuana in criminal court Part 3: What is microscopic morphological examination? Is it a “good” test?

The myth of specific identification of Marijuana in criminal court Part 3: What is microscopic morphological examination? Is it a “good” test?

On January 17, 2012, in Equipment, Identification, In The Courtroom, Solid Drug Dose, by Justin J. McShane

In this series of posts we are going to examine these seemly simple questions: What is the goal and the purpose of testing of unknowns generally? How do we best design a test for marijuana? How is most marijuana testing conducted in the United States? What is microscopic morphological examination? Is it a “good” test? […]

Hemolysis in a blood sample when using headspace analysis by GC-FID

Hemolysis in a blood sample when using headspace analysis by GC-FID

On December 21, 2011, in Chemistry, Equipment, GC-FID & GC/MS, Phlebotomy, by Justin J. McShane

Hemolysis is a particular problem in the proper quantification of EtOH in a blood sample. First let’s define what it is: What does it look like? Red blood cells without (left and middle) and with (right) hemolysis. If as little as 0.5% of the red blood cells are hemolyzed, the released hemoglobin will cause the […]

How the GC-FID arrives at a quantitative result: Auto-integration versus Manual Integration

How the GC-FID arrives at a quantitative result: Auto-integration versus Manual Integration

On December 1, 2011, in Chemistry, Equipment, GC-FID & GC/MS, In The Courtroom, Laboratory Procedure, Metrology, Standards, by Justin J. McShane

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 […]

A collosial waste of taxpayer money all in the name of forensics

A collosial waste of taxpayer money all in the name of forensics

On November 29, 2011, in DNA, Equipment, Ethics, Ethics: Lawyer, Ethics: Scientist, by Justin J. McShane

I have seen a lot of government waste all in the name of forensic science, but this one is utterly foolish. It needs nothing but it’s straight fact reporting… Flashy $330,000 DNA Bus Bought by County Designed by the company that built Dr. Oz’s jumbo bus, the vehicle will collect DNA samples and serve as […]