Forensic toxicology laboratories often encounter casework backlogs, which raise concerns for drug stability that can be affected by long storage times, temperature, and preservatives, or the lack thereof. The focus of this research was to evaluate the impact of these factors on the stability of 17 synthetic cannabinoids in human whole blood and 10 associated metabolites in human urine. The fortified biological specimens were stored under room temperature (20°C), refrigerator (4°C), and freezer (–20°C) conditions for a period of 52 weeks. Preservatives included potassium oxalate, sodium ethylenediaminetetraacetic acid, and sodium fluoride. Extraction of analytes was conducted using supported liquid extraction and analyzed using a liquid chromatograph-tandem mass spectrometer. Under all three storage conditions, the majority of urine metabolites were stable up to 9 weeks. All analytes in frozen sodium fluoride preserved blood were stable at 21 to 52 weeks with the exception of APP-PICA. Analytes in blood that were stable to 52 weeks in the freezer generally had a core structure of a carbonyl substituent on a pyrazole or pyrrole with surrounding nonpolar groups. In contrast, compounds with two adjacent polar carbonyl functional groups experienced degradation at 1 week or less under ambient temperature and refrigeration. 5-fluoropentyl analogs, XLR11 and 5-fluoro ADB-PINACA, in comparison to their counterpart analytes, UR144 and ADB-PINACA, were unstable at earlier time points under all temperatures. Based on these data, forensic blood evidence suggesting the presence of synthetic cannabinoid compounds are recommended to be frozen with sodium fluoride and potassium oxalate preservatives for optimal quantitative results.

中文翻译：

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使用 LC-MS/MS 评估精选苯乙酰吲哚、环烷基吲哚、喹啉基和甲酰胺合成大麻素的长期稳定性

法医毒理学实验室经常遇到案件积压的情况，这引起了人们对药物稳定性的担忧，药物稳定性可能会受到长期储存时间、温度和防腐剂或缺乏防腐剂的影响。本研究的重点是评估这些因素对人全血中 17 种合成大麻素和人尿液中 10 种相关代谢物稳定性的影响。强化生物样本在室温 (20°C)、冰箱 (4°C) 和冷冻柜 (–20°C) 条件下保存 52 周。防腐剂包括草酸钾、乙二胺四乙酸钠和氟化钠。使用支持液体萃取进行分析物的萃取，并使用液相色谱-串联质谱仪进行分析。在所有三种储存条件下，大多数尿液代谢物在长达 9 周内都是稳定的。除 APP-PICA 外，冷冻氟化钠保存的血液中的所有分析物在 21 至 52 周内均保持稳定。在冰箱中可稳定保存 52 周的血液中的分析物通常具有吡唑或吡咯上的羰基取代基以及周围的非极性基团的核心结构。相比之下，具有两个相邻极性羰基官能团的化合物在环境温度和冷藏下在 1 周或更短的时间内经历降解。5-氟戊基类似物 XLR11 和 5-氟 ADB-PINACA 与其对应分析物 UR144 和 ADB-PINACA 相比，在所有温度下在早期时间点都不稳定。根据这些数据，法医血液证据表明存在合成大麻素化合物，建议用氟化钠和草酸钾防腐剂冷冻，以获得最佳定量结果。