تسجيل الدخول

تسجيل

Quantification of drugs and other toxins

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  203

2026-10-12

19

Quantification of drugs and other toxins

The vast majority of drugs, metabolites and other toxins are quantified by GC or HPLC, increasingly in combination with MS detection. Simple GC or HPLC detection is usually based on the total peak area produced by the detector (e.g. NPD, flame ionisation detection (FID), UV, diode array detection (DAD)). GC-MS quantification, while it can be based on the total ion signal, is more usually based on the peak area for specific ion fragments – called selected-ion monitoring (SIM). For liquid chromatography coupled to mass spectrometry, MS-MS is more commonly employed to provide sensitivity and specificity. Quantification is still based on peak areas, typic ally of the product ion of the MS-MS transition monitored. By its nature, SIM GC-MS or LC MS/MS quantification is considerably more specific and often more sensitive than use of the more traditional GC or LC detectors. This is of particular importance in postmortem work, in which endogenous lipids and putrefactive products can produce significant interference. Other than detection techniques, there are two other major considerations in quantitative post mortem work. The first is the reproducibility and robustness of the extraction procedure. The second is the choice of an appropriate calibration method. Use of an appropriate assay design and sound extraction and calibration methods can minimise the effect of the matrix, especially if the calibrators are prepared in a similar matrix to that being analysed.