Prior to toxicological analysis, hair as a matrix requires pre-treatment measures including decontamination, homogenization and extraction. Decontamination is performed to differentiate between drug present from superficial deposition and drug incorporated from systemic distribution following ingestion. There are many methods for decontamination of hair samples, mostly developed by empirically using a traditional “one factor at a time” approach, in which one independent variable at a time is changed to observe the effect on the dependent variable. The goal of the present work was to compare the efficacy of decontamination protocols using statistical “design of experiments” (DoE), which allows for analysis of multiple variables and interactions within a single experiment. Decontamination parameters included identity of aqueous and organic wash solutions, number of sequential aqueous and organic washes, order of aqueous and organic washes, and duration of each wash. DoE studies were completed to identify optimal decontamination conditions for four abused drugs with varying physiochemical properties. For this purpose, drug-free human hair was externally contaminated with diazepam, heroin, cocaine or Δ⁹-tetrahydrocannabinol. Each analyte was found to have a unique set of decontamination conditions that were most effective. These included three 30-min washes with methanol followed by three with 1% sodium dodecyl sulfide for diazepam, three 30-s washes with dichloromethane followed by one with water for heroin, one 30-s wash with 1% sodium dodecyl sulfate followed by three with dichloromethane for cocaine and three 30-min washes with water followed by one with methanol for Δ⁹-tetrahydrocannabinol. The results provide proof-of-principle for a DoE approach to identify effective parameters for hair decontamination for a physicochemically diverse group of drugs. The major advantage of DoE is to elucidate combinations of parameters that result in effective removal of surface contamination, a goal that would be challenging to accomplish using a one factor at a time approach.

中文翻译：

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评估地西泮，海洛因，可卡因和Δ头发去污协议⁹通过实验的统计设计四氢大麻酚

在进行毒理学分析之前，以头发为基质需要采取预处理措施，包括去污，均质化和提取。进行净化处理以区分表层沉积的药物和摄入后全身分布的药物。毛发样品的净化方法有很多，多数是通过经验方法使用传统的“一次一个因素”方法开发的，其中一次更改一个自变量以观察对因变量的影响。本工作的目的是使用统计“实验设计”（DoE）比较去污方案的功效，该方法可以分析单个实验中的多个变量和相互作用。去污参数包括水和有机洗涤液的身份，水和有机洗涤的顺序数量，水和有机洗涤的顺序以及每次洗涤的持续时间。美国能源部（DoE）的研究已经完成，以确定四种具有不同理化特性的滥用药物的最佳去污条件。为此，无药的人发在外部受到地西epa，海洛因，可卡因或Δ的污染。^9-四氢大麻酚。发现每种分析物都有一套最有效的独特去污条件。其中包括用甲醇洗涤3次30分钟，然后用3％用1％十二烷基硫化钠洗涤地西di，用二氯甲烷洗涤3次30秒，然后用水洗涤海洛因一次，用1％十二烷基硫酸钠洗涤30次，再洗涤3次用二氯甲烷对可卡因和三个30分钟的洗涤用水，然后用一个用甲醇Δ ⁹-四氢大麻酚。该结果为DoE方法的原理提供了证明，以鉴定物理化学上多种多样的药物对头发进行去污的有效参数。DoE的主要优点是阐明可有效去除表面污染的参数组合，这一目标在一次使用一个因素的情况下很难实现。