Direct quantification of toxic substances in frozen tissues by MALDI-MS/MS

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K09206
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Legal medicine
• Research Institution: Hamamatsu University School of Medicine
• Principal Investigator: Minakata Kayoko 浜松医科大学, 医学部, 特任研究員 (70115509)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 質量分析 / 薬毒物 / 危険ドラッグ / 合成カンナビノイド / 代謝物

Outline of Final Research Achievements

The direct quantification method of toxic substances in tissues from a cadaver (intoxicated with diphenidine in this case) was devised. About 20 pieces of 20 μm-thick frozen tissue sections (5x5mm) were prepared. On a MALDI plate, standard solutions of diphenidine, tissue section and matrix were piled on successively, and diphenidine was quantified by MALDI-MS/MS using standard addition method. This result was reported in Forensic Toxicology 34:151, 2016. Much more sensitive method was required for the quantification of synthetic cannabinoids because they were metabolized very quickly and could not be determined by the previous methods in most cases. Our new method was devised based on liquid chromatography (LC)-QTRAP-MS/MS, and the LOQ of the method was 10 pg/mL (that is 1/100 of the LOQ in the previous reports). This method was applied successfully to several cases where toxic substances were unknown.

Free Research Field

医歯薬学

Academic Significance and Societal Importance of the Research Achievements

法医学や救急救命においては原因不明の中毒にしばしば遭遇し、薬毒物の迅速で信頼がおける分析が必要である。matrix assisted laser ionization (MALDI) tandem mass spectrometry (MS/MS) 法は試料をプレートに乗せ、装置に挿入すると20秒で結果が得られる迅速で高感度な質量分析法である。ヒト解剖組織の凍結切片にこの方法を適用することにより、ヒトにおける薬毒物の影響や組織中の局在箇所を特定するという学術的意義がある。薬毒物およびその代謝物の高感度で迅速な定量法を開発することにより中毒の原因解明という社会的意義がある。