Methylone determination in oral fluid using microextraction by packed sorbent coupled to ion mobility spectrometry

A methodology based on microextraction by packed sorbent (MEPS) followed by ion mobility spectrometry (IMS) has been developed for the simple and automated determination of methylone in oral fluids. MEPS was carried out using a 100 mu L eVol (R) XR hand-held automated analytical syringe filled with octadecyl silica sorbent. The effect of main experimental parameters of MEPS such as sample pH and ionic strength, number of aspirating/dispensing cycles, and elution solvent was studied to obtain a quantitative extraction of methylone. Oral fluid samples were spiked with methylone at different concentration levels from 50 to 400 mu g L-1 and analyzed by the proposed MEPS-IMS procedure, giving quantitative recoveries from 78 to 91% and precision values, estimated as the relative standard deviation, lower than 9%. The proposed MEPS-IMS method was tested under extreme conditions using spiked field saliva samples of volunteers in different situations such as 15 min after drinking coffee and syrup, and smoking cigarettes and cannabis with appropriate results. Moreover, results obtained by IMS were statistically comparable to those obtained by ultra high performance liquid chromatography - tandem mass spectrometry.