Approach to Optimization of Mass Spectrometric Detection Parameters for Identification of Ultra-Small Amounts of Highly Toxic Substances

The procedure of optimization of the following parameters is described: scanning speed, duration of registration of selective transitions (dwell time), duration of delay in transition from one selective transition to another (pause time). A chromatograph for HPLC with a three-quadrupole mass spectrometric detector (LC-MS/MS Shimadzu 8050) was used. Chromatographic separation was carried out on a column with reversed-phase sorbent Phenomenex Kinetex C18. As mobile phase A was used 0.1 % solution of formic acid in water with addition of 10 mM/L ammonium formate, as mobile phase B – 0.1 % solution of formic acid in methanol with addition of 10 mmol/L ammonium formate. The optimal parameters for confirmatory methods were established: duration of registration of selective transitions – not less than 10 ms, duration of delay in transition from one selective transition to another – 1 ms, scanning speed – from 1000 to 5000 scans per second. This technique has been successfully applied in routine chemical and toxicological studies of urine samples with low content of various narcotic and medicinal substances.