Sensitive Detection of Cyanide in Urine by HPLC ESI–MS/MS Combined with Derivatization Pretreatment

The high toxicity and availability in industrial production have made cyanide a concern for clinical testing and forensic toxicological analysis. An efficient and accurate method for detecting cyanide in urine sample has been established. The process was carried out by a two-step derivatization reaction. The cyanide reacted with benzaldehyde to form a stable intermediate which reacted with heptafluorobutyryl chloride in the second step. The quantitative MS/MS transition of the cyanide derivative was m/z 330.2→m/z 303.4, and the qualitative MS/MS transition was m/z 330.2→m/z 185.2. The method had good linearity (r2 = 0.999 4) and covered the cyanide poisoning detection window (0.01–10 µg mL− 1), and the limit of detection was 3 ng mL− 1. At the same time, the method demonstrated good accuracy (recoveries = 92.7.0–102.0%) and precision (intra-day precision = 3.3–5.1%, inter-day precision = 4.4–5.3%). The complete derivatization reaction and detection time were controlled within 20 min and successfully applied in a lethal case of ingestion of potassium cyanide.