Simultaneous Determination of Methamphetamine and Its Isomer N-Isopropylbenzylamine in Forensic Samples by Using a Modified LC-ESI-MS/MS Method

Accurate identification and quantification of methamphetamine (MA) its related substances are essential for the investigation fair trial drug offenses. In this study, a modified LC-ESI-MS/MS method simultaneous determination MA isomer N-isopropylbenzylamine (N-IBA) in forensic samples was developed validated. Optimum chromatographic separation target analytes achieved on an Agilent Poroshell 120 SB-C18 column ( 4.6 × 100 mm, 2.7 μm) at 40°C with isocratic elution flow rate 0.40 mL/min. The mobile phase acetonitrile 20 mM ammonium acetate solution containing 0.1% formic acid (80 : 20, id="M2"> v / ). Positive ESI-MS/MS detection performed multiple reaction monitoring (MRM) mode to identify quantify analytes. Method validation showed excellent linearity range 0.51 ng/mL~51 ng/mL N-IBA. low limit (LLOD) (LLOQ) reached 0.1 0.3 both satisfactory accuracy inter- intraday-relative error (RE) <20%, precision intraday relative standard deviation (RSD) less than 15%. validated successfully applied real resulted N-IBA 8 suspected cases that only deemed positive using our previous routine screening procedure, which avoided misidentification as MA.