Poetzsch Michael, Steuer Andrea E, Roemmelt Andreas T, Baumgartner Markus R, Kraemer Thomas
University of Zurich , Institute of Forensic Medicine, Department of Forensic Pharmacology & Toxicology, Winterthurerstrasse 190/52, CH-8057 Zurich, Switzerland.
Anal Chem. 2014 Dec 2;86(23):11758-65. doi: 10.1021/ac503193w. Epub 2014 Nov 17.
Single hair analysis normally requires extensive sample preparation microscale protocols including time-consuming steps like segmentation and extraction. Matrix assisted laser desorption and ionization mass spectrometric imaging (MALDI-MSI) was shown to be an alternative tool in single hair analysis, but still, questions remain. Therefore, an investigation of MALDI-MSI in single hair analysis concerning the extraction process, usage of internal standard (IS), and influences on the ionization processes were systematically investigated to enable the reliable application to hair analysis. Furthermore, single dose detection, quantitative correlation to a single hair, and hair strand LC-MS/MS results were performed, and the performance was compared to LC-MS/MS single hair monitoring. The MALDI process was shown to be independent from natural hair color and not influenced by the presence of melanin. Ionization was shown to be reproducible along and in between different hair samples. MALDI image intensities in single hair and hair snippets showed good semiquantitative correlation to zolpidem hair concentrations obtained from validated routine LC-MS/MS methods. MALDI-MSI is superior to LC-MS/MS analysis when a fast, easy, and cheap sample preparation is necessary, whereas LC-MS/MS showed higher sensitivity with the ability of single dose detection for zolpidem. MALDI-MSI and LC-MS/MS segmental single hair analysis showed good correlation, and both are suitable for consumption monitoring of drugs of abuse with a high time resolution.
单根毛发分析通常需要广泛的样品制备微观尺度方案，包括诸如分割和提取等耗时步骤。基质辅助激光解吸电离质谱成像（MALDI-MSI）已被证明是单根毛发分析中的一种替代工具，但问题仍然存在。因此，系统地研究了MALDI-MSI在单根毛发分析中有关提取过程、内标（IS）的使用以及对电离过程的影响，以实现其在毛发分析中的可靠应用。此外，还进行了单剂量检测、与单根毛发的定量相关性以及毛发片段的液相色谱-串联质谱（LC-MS/MS）结果分析，并将其性能与LC-MS/MS单根毛发监测进行了比较。结果表明，MALDI过程与天然毛发颜色无关，不受黑色素存在的影响。电离在不同毛发样品之间以及沿毛发长度方向上具有可重复性。单根毛发和毛发片段中的MALDI图像强度与通过经过验证的常规LC-MS/MS方法获得的唑吡坦毛发浓度具有良好的半定量相关性。当需要快速、简便且廉价的样品制备时，MALDI-MSI优于LC-MS/MS分析，而LC-MS/MS对唑吡坦具有单剂量检测能力，灵敏度更高。MALDI-MSI和LC-MS/MS分段单根毛发分析显示出良好的相关性，两者都适用于高时间分辨率的滥用药物消费监测。
