تسجيل الدخول

تسجيل

DEVELOPING AN ANALYTICAL SCHEME

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p344-345

2026-08-09

23

DEVELOPING AN ANALYTICAL SCHEME

Once the weight and sampling issues have been settled, then it is necessary to develop a scheme of analysis for the exhibits. This scheme will ordinarily proceed from general types of tests toward specific tests. For most drug analyses, the goal is to unequivocally identify all controlled substances in an exhibit. There are certain cases where this confirmation may not be done. These situations will be discussed later. Each exhibit should be treated as an unknown substance. Police officers or drug enforcement agents may already have a good idea what is contained in a drug exhibit and will usually relay this information to the drug chemist. Sometimes this information is based in part on some field-testing that the officer may have performed. Several companies sell field test kits that contain the chemicals necessary to perform a preliminary or presumptive test on a suspected controlled substance. These tests may be necessary for the law enforcement agency to establish probable cause to obtain a search warrant or for other purposes. Even if this test is performed the results are only preliminary and cannot be relied on for identification purposes. Therefore, although information about a drug case may be interesting and perhaps useful, it should not dissuade the drug chemist from treating each case as an unknown situation. One of the most important advances in the development and validation of analytical tests and schemes for drug analysis has been the work of the Scientific Working Group on Seized Drugs (SWGDRUG). This international committee of drug experts has been working for nearly 10 years on developing standards for the analysis of illicit drugs. SWGDRUG was formed and is funded by the United States DEA. It has developed standards for schemes of analysis, education and professional devel opment of drug chemists, quality assurance and control, sampling and statistical analysis. Its work is ongoing. Check their website at: www.swgdrug.org for more information and a listing of their standards.