Analysis of Desomorphine in Urine Using Liquid Chromatography-Tandem Mass Spectrometry.

Desomorphine is a primary component of the drug Krokodil. While reports of Krokodil use continue to appear in the literature, analytically confirmed cases remain quite scarce. This might be attributed to trends in geographical use, and limited published analytical methodology to detect its use. A sensitive analytical method to detect desomorphine was developed and validated to assist with identification efforts. Solid phase extraction and liquid chromatography-tandem mass spectrometry were used to quantitatively identify desomorphine in urine. An isotopically labeled analog was used as the internal standard. Assay performance was evaluated in accordance with published guidelines. The extraction efficiency for desomorphine in urine was 90%, and limits of detection and quantitation were 0.5 ng/mL. The calibration range of the assay was 0.5-500 ng/mL. Bias ranged from -1% to 2% (n = 15), and the intra- and inter-assay CVs were 2-3% (n = 3) and 32-6% (n = 15), respectively. Ion suppression was -20% and -10% at low and high concentrations, respectively. Interferences were assessed using common drugs, including 24 opioids and structurally related compounds. Using this approach, the quantitative analysis of desomorphine in urine is described at forensically relevant concentrations.