New psychoactive substances (NPS) are often synthesized via small changes in the molecular structure, producing drugs whose effect and potency are not yet fully known. Ketamine is one of the oldest NPS, with therapeutic use in human and veterinary medicine authorized in several countries, being metabolized mainly into norketamine and 6-hydroxy-norketamine. Furthermore, two structural analogues of ketamine have recently been identified, deschloroketamine and 2-fluorodeschloroketamine, marketed as drugs of abuse. To comply with Green Analytical Toxicology (GAT) fundamentals, miniaturized techniques such as dispersive liquid–liquid microextraction (DLLME) were employed to determine toxicants in biological fluids. An analytical method for determining ketamine, its metabolites and its analogues in oral fluid was fully developed and validated by using DLLME and liquid chromatography–tandem mass spectrometry (LC-MS-MS). The extraction parameters were optimized by multivariate analysis, obtaining the best conditions with 200 μL of sample, 100 μL of methanol as dispersive solvent and 50 μL of chloroform as extractor solvent. Linearity was obtained from 10 to 1,000 ng/mL, with limit of detection (LOD) and lower limit of quantification (LLOQ) at 10 ng/mL. Imprecision (% relative standard deviation) and bias (%) were less than 8.2% and 9.5%, respectively. The matrix effect did not exceed 10.6%, and the recovery values varied from 24% to 42%. No matrix interference and good selectivity in the evaluation of 10 different sources of oral fluid and 42 drugs at 500 ng/mL, respectively, were observed. The method was applied in the analysis of 29 authentic oral fluid samples and had its green characteristic evaluated by three different tools: the Green Analytical Procedure Index (GAPI), the Analytical Eco-Scale and the Analytical GREEnness (AGREE) metrics.

中文翻译：

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使用分散液液微萃取 (DLLME) 测定口腔液样品中氯胺酮、其代谢物和类似物的绿色分析毒理学程序

新的精神活性物质（NPS）通常是通过分子结构的微小改变来合成的，所产生的药物的作用和效力尚不完全清楚。氯胺酮是最古老的新型精神活性物质之一，多个国家批准其在人类和兽医医学中的治疗用途，主要代谢为去甲氯胺酮和 6-羟基去甲氯胺酮。此外，最近还发现了氯胺酮的两种结构类似物，即去氯氯胺酮和2-氟去氯氯胺酮，它们作为滥用药物销售。为了符合绿色分析毒理学 (GAT) 基本原理，采用分散液液微萃取 (DLLME) 等微型技术来测定生物液体中的毒物。使用 DLLME 和液相色谱-串联质谱 (LC-MS-MS) 完全开发并验证了测定口腔液中氯胺酮、其代谢物及其类似物的分析方法。通过多因素分析优化提取参数，得出最佳条件为：样品200 μL，甲醇100 μL为分散溶剂，氯仿50 μL为提取溶剂。线性范围为 10 至 1,000 ng/mL，检测限 (LOD) 和定量下限 (LLOQ) 为 10 ng/mL。不精密度（% 相对标准偏差）和偏倚 (%) 分别小于 8.2% 和 9.5%。基质效应不超过10.6%，回收率从24%到42%不等。在分别评估 10 种不同来源的口腔液和 500 ng/mL 的 42 种药物时，没有观察到基质干扰和良好的选择性。该方法应用于29个真实口腔液样品的分析，并通过三种不同的工具评估其绿色特征：绿色分析程序指数（GAPI）、分析生态量表和分析绿色度（AGREE）指标。