Forensic chemists can quickly determine the species of origin of a blood sample or blood stain by determining the molecular weight of the alpha and beta chains of hemoglobin. Credit: USFWS

CHEMISTRY UNIT

The primary activities of the Chemistry Unit in casework focus on the elucidation of molecules that assist in answering questions concerning cause of death and species identifications.  While the approaches to molecular elucidations are as varied as the molecules under investigation, many methods incorporate mass spectrometry as a vital component of the analyses performed.  As such, the Chemistry Unit has a diverse array of mass spectrometers that include:

1. An Agilent 6890 gas chromatograph equipped with a 5973 mass select detector and an Agilent 6890N gas chromatograph equipped with a 5975B mass select detector.
2. A Varian CP-3800 gas chromatograph equipped with a Saturn 2200 ion-trap mass spectrometer and associated CTCAnalytics COMBIPAL automated injector with solid phase microextraction (SPME) capacity.
3. A ThermoFinnigan LCQ DecaXP ion-trap mass spectrometer.
4. An Applied Biosystems Voyager-DE PRO MALDI mass spectrometer.
5. An Ion Spec Fourier Transform mass spectrometer equipped with a 7.0T magnet.

In addition to the above mass spectrometric systems, the Chemistry Unit utilizes the following instrumentation to help in molecular characterizations: an Agilent 1200 Series high performance liquid chromatograph equipped with a Pickering PCX 520 postcolum derivatization unit; an Agilent 1200 Series capillary high performance liquid chromatograph; a ThermoNicolet NEXUS 470 Fourier transform infrared spectrometer equipped with a Centaurus microscope; and an EDAX  Eagle II x-ray fluorescence spectrometer.

    Assistance in cause of death determinations can focus on the identification of a particular agricultural poison (organophosphates or carbamates); a particular mammalian pest control agent (strychnine, anticoagulants, or sodium fluoroacetate); an avian pest control agent such as 4-aminopyridine; or the identification of petroleum hydrocarbons found on/in “oiled” birds.  Support in the area of species identifications encompasses characterization of heme proteins from blood and tissue samples; characterization of bile acids from gall bladders and Asian medicinal products; or characterization of keratins from products made of rhino horn or tortoise shell.

For more information, please view our Chemistry publications.

BACK TO TOP