GC-MS determination of hydroxylamine in blood and urine

Abstract

A GC-MS method was developed for hydroxylamine (HA) quantitation in blood plasma and urine. Feature of this method is two stages of derivatization: benzaldehyde and bistrimethylsilyltrifluoroacetamide. HA is a highly polar, hydrophilic, low-weight basic compound. We tried a variety of approaches to derivatization and isolation of HA from water phase: simultaneous extraction and derivatization HA with acetone, extraction of acetone oxime using head-space solid phase microextraction, benzaldehyde derivatization and extraction into an organic phase of the resulting oxime and finally, a twin stage derivatization with benzaldehyde and bis-trimethylsilyltrifluoroacetamide, which has been recognized by us the best option. LOD of GC-MS method is 30 ng/mL, but using GC-MS/MS allow us to reduce LOD to 0.1 ng/mL. Quantification was performed by using relative calibration with methoxyamine as internal standard. Toxicological experiments with experimental animals were carried out in order to establishing possibilities of our method for diagnostics of acute and chronic intoxication of hydroxylamine. It was shown that GC-MS are possible to diagnose just acute poisoning hydroxylamine (SLD50), but GC-MS/MS are possible to diagnose chronic intoxication by HA (2 mg/L in drinking water). Refs 16. Figs 4. Tables 2.