Forensic Chemistry is the application of chemistry in the forensics field. Forensics not only has to be efficient but also reliable and accurate as results can be used in a court setting. Crime scenes are often examined employing chemistry. Residual fire residue, drugs and unknown materials are often assessed using forensic techniques. Furthermore, impaired driving can be tested through a blood alcohol test.
One simple way to examine forensic samples is by static headspace. Static headspace is a non-exhaustive sampling technique, samples are brought to equilibrium through heating and agitation and an aliquot of the sample headspace is sampled and injected into a Gas Chromatograph for separation and a detector for analysis. Static headspace is a common technique for the determination of blood alcohol content or volatile compound sampling.
Solid Phase Microextraction or SPME is a semi-exhaustive sampling technique that uses a phase coated fiber to extract analytes from a sample. The phase coating chosen is dependent on the compounds to be extracted from the sample. Typically, a SPME fiber is inserted into the headspace or the solution of the sample while being heated and agitated. The fiber is then removed from the vial and inserted into a GC inlet and desorbed for a length of time for compound separation and analysis. The examination of fire accelerants is one analysis that uses a SPME fiber for arson forensics.
The Flex robotic sampling platform can be used for all three of these forensic sampling techniques. So, if you are just getting started with forensic sampling and analysis, contact us to reach one of our application specialists who would be glad to offer some tips and tricks. Feel free to look at some of our application notes which will help you on your way.
There are several ways to determine the amount of alcohol that is in a person’s system. The most common methods are breath analysis in the field and blood analysis in the lab. Blood alcohol determination in the laboratory is used predominantly when a person refuses a breath test. In order to determine blood alcohol content, a person’s blood has to be withdrawn as soon as possible after the occurrence. Furthermore, the blood needs to be collected in duplicate in order to confirm the test results. This application note will examine static headspace sampling of alcohol standards using Gas Chromatography (GC) for separation and Flame Ionization Detection (FID) for analysis. The linearity of the compounds of interest will be examined and compared using a secondary column for confirmation. Additionally, as many forensic labs have an excess of samples to examine, the use of software innovations will aid in optimizing sample throughput.