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Single hair analysis: Validation of a screening method for over 150 analytes and application on documented single‐dose cases
Author(s) -
Wiedfeld Christopher,
Skopp Gisela,
Musshoff Frank
Publication year - 2021
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.2997
Subject(s) - analyte , resolution (logic) , hair analysis , chromatography , maxima , segmentation , chemistry , medicine , computer science , artificial intelligence , pathology , art , alternative medicine , performance art , art history
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.