Meier Ulf, Briellmann Thomas, Scheurer Eva, Dussy Franz
Institute of Legal Medicine of the University of Basel, Forensic Chemistry and Toxicology, Pestalozzistrasse 22, CH-4056, Basel, Switzerland.
Drug Test Anal. 2017 Oct;9(10):1594-1603. doi: 10.1002/dta.2186. Epub 2017 May 11.
The distribution of analyte concentrations in hair across the scalp has not been thoroughly investigated. Differences in concentrations depending on sampling location are problematic, especially when measuring a second strand to confirm the result of the first measurement. Aiming at a better understanding of the concentration differences, the distribution of ethyl glucuronide (EtG) and caffeine concentrations in hair across the entire head of one test subject was investigated by dividing the scalp completely into regions of ca 2 cm × 2 cm area, yielding a total of 104 samples. For the quantification of EtG, a novel LC-MS /MRM method was developed and validated with a limit of detection and limit of quantification of 2 and 4 pg/mg, respectively. Large variations of the concentration across the head were found, with factors of ca 3.0 and 10.6 for EtG and caffeine, respectively. These differences could not be attributed to measurement error alone. The concentrations were projected onto the subject's head, and concentration patterns were identified for EtG and caffeine. When examining multiple strands from within one 2 cm × 2 cm sampling area, the strands showed similar concentrations. Segmental analysis of selected 3 cm strands showed decreasing concentrations of EtG and caffeine from proximal to distal end, possibly due to wash-out of the analytes. Copyright © 2017 John Wiley & Sons, Ltd.
头皮上毛发中分析物浓度的分布尚未得到充分研究。取决于采样位置的浓度差异存在问题，尤其是在测量第二缕毛发以确认第一次测量结果时。为了更好地理解浓度差异，通过将一名受试者的整个头皮完全划分为约2厘米×2厘米面积的区域，共得到104个样本，研究了毛发中葡萄糖醛酸乙酯（EtG）和咖啡因浓度的分布。对于EtG的定量分析，开发并验证了一种新型液相色谱 - 质谱/多反应监测（LC-MS / MRM）方法，其检测限和定量限分别为2 pg/mg和4 pg/mg。发现整个头部的浓度变化很大，EtG和咖啡因的变化因子分别约为3.0和10.6。这些差异不能仅归因于测量误差。将浓度投影到受试者的头部，并确定了EtG和咖啡因的浓度模式。当检查来自一个2厘米×2厘米采样区域内的多缕毛发时，这些毛发显示出相似的浓度。对选定的3厘米长毛发进行的分段分析表明，从近端到远端，EtG和咖啡因的浓度逐渐降低，这可能是由于分析物的洗脱。版权所有© 2017约翰威立父子有限公司。
