This adorable little wiry girl is “Sky” – or to be more accurate “GCh AfterAll Painting The Sky.” Americas most prestigious canine club named her the top dog at the 2014 Westminster Kennel Club dog show. Want to know more about Sky’s family tree? Thats easy. We can just hop on the internet and trace her […]
Why so Low? Rule 702 “Hurdle” and who is an expert
Why so Low? Rule 702 “Hurdle” and who is an expert If you stopped and asked anyone (other than a lawyer) what type of education, training and experience one would have to have in order to be qualified in court as an expert witness, you will get varying responses. Some will say PhD. Others will […]
Another week another forensic laboratory scandal. It’s the Wild Wild West
With no standardization of methods, a whole scale lack of basic validity, and a lack of meaningful oversight, today’s forensic laboratory system is beyond “badly fragmented.” It is utterly lawless. It is like the Wild Wild West. Like I have written before (Why Don’t we Six Sigma Forensic Science? It’s all about method validation, traceability, […]
Some random thoughts on forensic science
While at the ACS press conference last week, I was asked by an international reporter my thoughts on the current state of affairs in Forensic Science by a Brazilian science reporter. I wanted to share my answers with you all and see if there are different points of view that may be out there. So […]
Where is the commutability?
Commutability is the hallmark of all measurement science and is particularly important in analytical chemistry at large. Commutability is the feature of being comparable across borders and universal over all time. Using appropriate and traceable standards/reference materials during calibration combined with using validated and standardized methods provides for commutability. Since the mid 1980s, the Environmental […]
Why Don’t we Six Sigma Forensic Science? It’s all about method validation, traceability, and quality assurance
The goal of any form of identification or quantitation is to produce a specific and true expression that is valid. In the forensic world how we scientifically arrive at a reported result should not be an act of mysterious busywork, but rather a result of planned, purposeful meaningful action that is validated and truly scientific. […]
Quality Control in GC-FID: Teaching the machine right from wrong
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 […]
How the GC-FID arrives at a quantitative result: Auto-integration versus Manual Integration
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 […]
Limitations of Forensic Odontology
In the past, we have blogged on the severe limitations on pattern recognition as a forensic science discipline. (Pattern Recognition is it Science or an Art?). In fact, the National Research Council of the National Academy of Sciences pointed to one form a pattern recognition as being most problematic: forensic odontology. Most broadly defined, it is […]
Standards, Controls, Calibrators, and Verifiers, 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 […]
Mass Spectroscopy for Lawyers Part 7: How do they quantitate the results?
In a series of posts, we are going to talk about Mass Spectrometry. Introduction-The different configurations and the Electron Impact process What types of mass analyzers are there? What type of detectors are there? What types of analysis can be done? How do you read the output? How do they come to a qualitative measure […]
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