Switchable Hydrophilicity Solvent-Based Homogenous Liquid–Liquid Microextraction (SHS-HLLME) Combined with GC-FID for the Quantification of Methadone and Tramadol

• Published in: Chromatographia Vol. 81; no. 7; pp. 1063 - 1070
• Main Authors: Ahmar, Hamid, Nejati-Yazdinejad, Massoud, Najafi, Mozhgan, Hasheminasab, Kobra Sadat
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2018; Springer Nature B.V
• Subjects: Analytical Chemistry; Carbon dioxide; Chemistry; Chemistry and Materials Science; Chromatography; Extraction processes; Hydrophilicity; Laboratory Medicine; Linearity; Methadone; Miscibility; Original; Pharmacy; Proteomics; Reagents; Solvents; Urine; Switchable hydrophilicity solvent; Homogeneous liquid–liquid microextraction; Methadone; Dipropylamine; Tramadol
• ISSN: 0009-5893; 1612-1112
• DOI: 10.1007/s10337-018-3528-y

In this work, a new method based on homogeneous liquid-phase microextraction was developed for the determination of methadone and tramadol. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible/immiscible upon the addition or removal of CO 2 as a reagent. The effects of operational parameters of the extraction such as volume of acceptor phase, volume of donor phase, pH of donor phase, and ionic strength of solution were investigated. Under optimal conditions, the preconcentration factors, the detection limits and the linearity of the method were achieved in the ranges of 135–138, 1.2 and 4–1000 µg L −1 , respectively. Finally, the proposed method has been successfully applied to the analysis of methadone and tramadol in urine samples. In urine sample, the preconcentration factors were 118 and 122 for methadone and tramadol, respectively. Additionally, calibration curves were found to be linear in the concentration range of 8–1000 µg L −1 with the r 2 values better than 0.998. In addition, limits of detection and quantification were 2.4 and 8 µg L −1 , respectively, for both analytes.