Hair is the matrix of choice in forensic toxicology when retrospective analysis is needed. Nonetheless, due to misalignment, different growth stages and segmentation lengths of 0.5–1 cm, resolution of time is limited. By segmental analysis of single hairs, most of these factors can be compensated and resolution of time is enhanced. A method for manually segmenting single hairs in 2‐mm sections and screening for 156 analytes by liquid chromatography coupled to tandem mass spectrometry has been developed and validated. The method was applied to 15 single‐dose cases concerning different pharmaceuticals by analyzing 10 hairs each, sampled 1 and 2 months after ingestion in most cases. The validation showed a lower limit of quantification of ≤1.25 pg/segment for ~90% of analytes and good accuracy. Many substances could be detected in the presented cases, whereas detection of benzodiazepines and low dosed opioids remains challenging. In positive cases, characteristic peak‐shaped concentration profiles across the hairs were obtained. The segment with most coinciding peak maxima can be allocated to the time of ingestion. A method for the determination of individual hair growth rate was applied and revealed a gap between expected and actual position of peak maxima. Additionally, different localization of simultaneously administered substances was observed. These findings were tried to be explained by different routes of incorporation and may contribute to current knowledge. The presented method may directly be applied to similar questions in hair analysis, and the findings are considered important for interpreting further results in single hair analysis.

中文翻译：

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单发分析：对超过 150 种分析物的筛选方法的验证以及在记录的单剂量病例中的应用

当需要进行回顾性分析时，头发是法医毒理学的首选基质。尽管如此，由于未对准、不同的生长阶段和 0.5-1 厘米的分割长度，时间分辨率是有限的。通过对单根毛发进行分段分析，可以补偿大部分因素，提高时间分辨率。已经开发并验证了一种手动分割 2 毫米切片中的单根头发并通过液相色谱与串联质谱联用筛选 156 种分析物的方法。该方法应用于 15 个单剂量病例，涉及不同药物，每个病例分析 10 根头发，在大多数情况下在摄入后 1 个月和 2 个月取样。验证表明，约 90% 的分析物的定量下限≤1.25 pg/segment，并且具有良好的准确度。在所呈现的案例中可以检测到许多物质，而苯二氮卓类药物和低剂量阿片类药物的检测仍然具有挑战性。在阳性情况下，获得了整个头发的特征峰形浓度分布。可以将具有最重合峰值最大值的段分配给摄取时间。应用了一种确定个体毛发生长速率的方法，并揭示了峰值最大值的预期位置与实际位置之间的差距。此外，观察到同时给药的物质的不同定位。这些发现试图通过不同的结合途径来解释，并可能有助于当前的知识。所提出的方法可以直接应用于头发分析中的类似问题，并且研究结果被认为对于解释单根头发分析中的进一步结果很重要。