Evaluation of Laser Diode Thermal Desorption (LDTD) for High Throughput Analysis of Controlled Substances and Toxicology in Forensic Sciences

摘要

The abundance of drug-related cases causes backlogs in forensic laboratories, which creates budgetary and policy problems and potentially compromises investigations. The laser diode thermal desorption (LDTD) source, coupled with MS, has demonstrated its applicability in other scientific areas by providing data comparable to traditionally used instrumentation, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), in less than half of the time without the need for commonly used laboratory consumables such as analytical columns. We evaluated LDTD coupled with triple quadrupole (QQQ) MS for the high-throughput quantitative analysis of controlled substances and drug toxicology in forensic laboratories. One hundred eleven drugs of abuse were optimized in methanolic drug solutions (e.g., designer drugs, controlled substances). Forty-nine compounds across major drug classes were spiked into drug-free human urine and blood for validation of screening or quantitative analysis. Liquid-liquid extraction (LLE) or solid phase extraction (SPE) methods were used for both urine and blood matrices for the extraction of drug analytes of interest. The goal was to utilize minimal sample preparation in order to increase overall sample analysis efficiency. The following parameters were evaluated for screening validation: carryover, interference, limit of detection (LOD), and matrix effect. The same parameters were evaluated for quantitative method analysis, in addition to limit of quantitation (LOQ), linearity, precision and accuracy, calibration model, and stability. Advantages of the LDTD system include (1) quick installation; (2) little instrument training; (3) no additional software requirement; (4) ease of use; (5) minimal maintenance; (6) rapid sample analysis; (7) minimal sample volume; (8) lack of chromatographic solvents and consumables; and (9) the ability to use across multiple MS platforms.