Abstract：
Kratom is a natural psychoactive product known primarily in Southeast Asia, including Thailand, Malaysia, etc. It is also known as krathom, kakuam, ithang, thom (Thailand), biak-biak, ketum (Malaysia) and mambog (Philippines) and is sometimes used as an opium substitute. It is stimulant at doses of 1-5 g, analgesic at doses of 5-15 g and euphoric and sedative at doses of >15 g. Mitragynine is the most abundant indole compound in kratom (Mitragyna speciosa) and is metabolized in humans to 7-hydroxymitragynine, the more active metabolite. Adverse effects include seizures, nausea, vomiting, diarrhea, tachycardia, restlessness, tremors, hallucinations and death. There are few studies on the analytical method for the detection of mitragynine and 7-hydroxymitragynine in hair. Therefore, this study proposes a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the analysis of kratom in hair. Hair samples were first weighed to ∼10 mg and washed with methanol. Then the washed hair samples were cut into pieces and incubated in methanol with stirring and heating (16 h/38℃). Extracts were then analyzed by LC-MS-MS. This method was validated by determining the limit of detection (LOD), limit of quantification, linearity, intra- and inter-day accuracy and precision, recovery and matrix effects. The intra- and inter-day precision (CV%) and accuracy (bias%) were within ±20%, which was considered acceptable. Using this newly developed LC-MS-MS method, the simultaneous detection of mitragynine and 7-hydroxymitragynine in six authentic hair samples was achieved to provide the direct evidence of kratom use in the past. Mitragynine concentrations ranged from 16.0 to 2,067 pg/mg (mean 905.3 pg/mg), and 7-hydroxymitragynine concentrations ranged from 0.34 to 15 pg/mg (mean 7.4 pg/mg) in six authentic hair samples from kratom abusers. This may be due to the higher sensitivity of the LOD in this study, with values of 0.05 pg/mg for mitragynine and 0.2 pg/mg for 7-hydroxymitragynine in hair.
摘要：
Kratom是一种天然的精神活性产品，主要在东南亚闻名，包括泰国,马来西亚等。它也被称为krathom，kakuam,ithang,thom(泰国),biak-biak,ketum(马来西亚)和mambog(菲律宾)，有时被用作鸦片替代品。它是1-5g剂量的兴奋剂，5-15g剂量的镇痛剂，在15g以上的剂量下可以兴奋和镇静。Mitragynine是kratom（Mitragynaspeciosa）中最丰富的吲哚化合物，在人类中代谢为7-羟基mitragynine，更活跃的代谢物。副作用包括癫痫发作，恶心,呕吐,腹泻,心动过速,躁动,震颤,幻觉和死亡。关于头发中mitragynine和7-羟基mitragynine的分析方法的研究很少。因此,这项研究提出了一种液相色谱-串联质谱（LC-MS-MS）方法来分析头发中的kratom。首先将毛发样品称重至约10mg并用甲醇洗涤。然后将洗过的毛发样品切成块,并在搅拌和加热(16h/38°C)下在甲醇中孵育。然后通过LC-MS-MS分析提取物。通过测定检测限(LOD)对该方法进行了验证,定量限(LOQ)，线性度日内和日间准确度和精确度，恢复和基质效应。日内和日间精度（CV％）和准确性（偏差％）在±20％以内，这被认为是可以接受的。使用这种新开发的LC-MS-MS方法，在六个真实的头发样本中同时检测到mitragynine和7-羟基mitragynine，为过去使用kratom提供了直接证据。Mitragynine浓度范围为16.0至2,067pg/mg（平均905.3pg/mg），在六个kratom滥用者的真实头发样品中，7-羟基mitragynine的浓度范围为0.34至15pg/mg（平均7.4pg/mg）。这可能是由于本研究中LOD的敏感性较高，头发中的mitragynine值为0.05pg/mg，7-羟基mitragynine值为0.2pg/mg，分别。
