Analysis of Cathinones in Plasma Using LC-MS/MS

Cathinones better known as bath salts have been listed as illicit drugs since 2011 and are the structural analog of Drug Enforcement Agency (DEA) Schedule I and II substances. They have been banned in numerous countries. Newly synthesized cathinones, which mimic the effects of illegal drugs of abuse and bypass the provisions of drug regulations, are still available. These products have caught concern among law enforcement agencies. Acute toxicity and numerous fatalities have been linked with the abuse of designer cathinones. Despite the increased availability of designer drugs, few studies have focused on the analytical extraction techniques and the matrix effect for their detection and quantification in biological samples. Accurately quantifying the concentration of cathinones in biological samples is important for the regulation of cathinones. LC-MS/MS is commonly used for detecting cathinones.
However, Concheiro et al. (2013) showed the matrix suppression was observed in urine sample of cathinones by LC-MS/MS analysis. Endogenous interferences in urine have suppressed cathinone, mephedrone, and 3,4-methylenedioxypyrovalerone (MDPV) detections by LC-MS/MS up to 27%, 11%, and 9%, respectively. This study was aimed to elucidate the plasma matrix effect on the quantification of these three cathinones by LC-MS/MS. We developed LC-MS/MS methods that utilize standard addition without internal standard. A mixture of cathinone and mephedrone in plasma was analyzed.