In suspected overdose cases, the quantity of the drug found in the person's system can confirm or rule out overdose as the cause of death. The instruments used by forensic chemists can detect minute quantities, and accurate measurement can be important in crimes such as driving under the influence as there are specific blood alcohol content cutoffs where penalties begin or increase.
įorensic chemists also help to confirm or refute investigators' suspicions in drug or alcohol cases. For example, an investigation that involves ricin would tell investigators to look for ricin's precursors, the seeds of the castor oil plant. During poisoning investigations, the detection of specific poisons can give detectives an idea of what to look for when they are interviewing potential suspects. On the other hand, the identification of TNT would create a wider suspect list, since it is used by demolition companies as well as in the military. For example, in explosive investigations, the identification of RDX or C-4 would indicate a military connection as those substances are military grade explosives. Forensic chemists can also narrow down the suspect list to people who would have access to the substance used in a crime. During fire investigations, forensic chemists can determine if an accelerant such as gasoline or kerosene was used if so, this suggests that the fire was intentionally set. The identification of the various substances found at the scene can tell investigators what to look for during their search.
įorensic chemists' analysis can provide leads for investigators, and they can confirm or refute their suspicions. To ensure the accuracy of what they are reporting, forensic chemists routinely check and verify that their instruments are working correctly and are still able to detect and measure various quantities of different substances.Ĭhemists were able to identify the explosive ANFO at the scene of the Oklahoma City bombing. In addition to the standard operating procedures proposed by the group, specific agencies have their own standards regarding the quality assurance and quality control of their results and their instruments. Forensic chemists follow a set of standards that have been proposed by various agencies and governing bodies, including the Scientific Working Group on the Analysis of Seized Drugs. Forensic chemists prefer using nondestructive methods first, to preserve evidence and to determine which destructive methods will produce the best results.Īlong with other forensic specialists, forensic chemists commonly testify in court as expert witnesses regarding their findings. The range of different methods is important due to the destructive nature of some instruments and the number of possible unknown substances that can be found at a scene. These include high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, Fourier transform infrared spectroscopy, and thin layer chromatography. Specialists in this field have a wide array of methods and instruments to help identify unknown substances. A forensic chemist can assist in the identification of unknown materials found at a crime scene. Forensic chemistry is the application of chemistry and its subfield, forensic toxicology, in a legal setting.
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