Quantitative analysis of 3,4-dimethylmethcathinone in blood and urine by liquid chromatography–tandem mass spectrometry in a fatal case

• We developed an analytical method for 3,4-dimethylmethcathinone (3,4-DMMC) in biological samples and applied it to a case.
• Sample extraction was performed with a modified QuEChERS method, and the extracts were analyzed with LC–MS/MS.
• 3,4-DMMC was detected in both blood and urine at high levels and a number of metabolites were also detected.

We report here the quantitative analysis of cathinone-type designer drug 3,4-dimethylmethcathinone (3,4-DMMC) in blood and urine using liquid chromatography–tandem mass spectrometry (LC–MS/MS) in a fatal case. Abuse of 3,4-DMMC is widespread and a global issue. However, to date, there have been no reports of 3,4-DMMC-related deaths. We encountered a death in which 3,4-DMMC was thought to play a causative role, and successfully identified this designer drug from biological samples by using LC–MS/MS and QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. For standard samples, detection of 3,4-DMMC in human blood and urine samples in the calibration range (5–400 ng/mL) was successful with recoveries of 85.9−89.4% (blood) and 95.8−101% (urine), limits of detection of 1.03 (blood) and 1.37 ng/mL (urine) and limits of quantification of 5.00 (blood) and 5.38 ng/mL (urine). The concentrations of 3,4-DMMC in blood (external iliac vein) and urine in the case were 27 mg/L and 7.6 mg/L, respectively. Some metabolites, including 3,4-dimethylcathione (DMC) and β-ketone reduced metabolites (β-OH-DMMC and β-OH-DMC), were detected in both blood and urine.