VALIDATION AND OPTIMIZATION OF ULTRASOUND-ASSISTED DISPERSIVE LIQUID-LIQUID MICROEXTRACTION AS A PREPARATION METHOD FOR DETECTION OF METHADONE IN SALIVA WITH GAS CHROMATOGRAPHY-MASS SPECTROMETRY TECHNIQUE

Background and Aim : In forensic and clinical toxicology, alkaline drugs like methadone are commonly extracted from biological samples. In this study we investigated validation and optimization of Ultrasound-assisted dispersive liquid-liquid microextraction (UADLLME) as a preparation method for detection of methadone in saliva samples. Methods : We obtained 50 blank and 50 methadone-containing saliva samples. Sodium hydroxide and chloroform were added to samples and they were held in ultrasonic bath for 1, 3, 5 and 7 minutes. Then samples were centrifuged and analyte was obtained from organic phase and injected to gas chromatography-mass spectrometry (GC-MS) device. Results : Intra and between-day accuracies were measured by mean relative error which was in the range of -2.3-7.5%. Recovery was between 81.2% and 97.1%. Precision in terms of coefficient of variation varied from 11.3% in methadone concentration of 150ng/ml to 5.2% in concentration of 10000ng/ml. Method was linear in the concentration range of 150 ng/ml-10 µl/ml with R2 of 0.99. Limit of detection and quantification were 50 and 150 ng/ml, respectively. Specifity of UADLLME was measured by comparing retention times of saliva samples (containing methadone and 4 other commonly used drugs) and there were no interferences. In comparison of traditional dispersive liquid-liquid microextraction (DLLME) and UADLLME, efficiency of UADLLME was 1.4 of DLLME. Solvent and sample volumes required for UADLLME were 1/200 and 1/20 of DLLME. The greatest efficiency obtained at PH of 10 and with ultrasound treatment duration of 5 minutes. Conclusion : Study found UADLLME/GC-MS a valid and efficient method for detection of methadone in oral fluid.

کلیدواژه ها:

Dispersive Liquid-liquid microextraction ، Gas chromatography-mass spectrometry ، Ultrasound ، Methadone ، Saliva ، Validation