Determination and quantitative analysis of designer drugs in human urine by liquid chromatography-mass spectrometry

A robust liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-ITMS) method was developed and utilized for the determination and quantitative analysis of four designer drugs in human urine. Designer drugs, including methcathinone (MC), 3,4-methylenedioxymethcathinone (MDMC), methylenedioxy-pyrovalerone (MDPV) and 40-methyl-alpha-pyrrolidinopropiophenone (MPPP) were determined by LC-ESI-ITMS under the optimal chromatographic separation conditions, and the precursor and major product ions of them were monitored in positive ion detection mode as m/z 164.0/146.0, m/z 208.0/190.1, m/z 276.2/205.0 and m/z 218.1/147.0, respectively. Linear calibration curves showed good linearity in the range 0.010-5.00 mu g mL(-1), with coefficients of greater than 0.9988. The method was validated with the intra-day and inter-day precisions represented by relative standard deviation of less than 5.3% in human urine, and the recoveries from spiked urine samples varied from 79.5% to 94.6%. The obtained results indicated that the method was rapid, sensitive and selective, and it could be applied in the determination of designer drugs in addict cases.