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

Purpose: 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 used blank and methadone-containing saliva samples and also standard methadone solution. Sodium hydroxide and chloroform were added to samples and they were held in ultrasonic bath. Then preparations were centrifuged and extracted analyte was analyzed by gas chromatography-mass spectrometry (GC-MS). Accuracy was measured by Intra and between-day mean relative errors (RE). Precision was assessed by coefficient of variation (CV). Recovery, specifity, linearity and limits of detection and quantification were determined. Optimized ultrasound duration and pH were also investigated. Efficiency of traditional dispersive liquid-liquid microextraction (DLLME) and UADLLME were compared.Results: Intra and between-day accuracy (2.3% -7.5%), recovery (89.4%-115.5%) and precision (5.2-11.3%) were all in the acceptable range. Method was linear in the concentration range of 150 ng/ml-10 μl/ml with R2> 0.99. Limits of detection and quantification were 50 and 150 ng/ml, respectively. Specifity was measured by comparing retention times of saliva samples (containing methadone and 4 other commonly used drugs) during UADLLME/GC-MS analysis and no interference was observed. Recovery 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 that UADLLME/GC-MS is 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