Combination of Electromembrane Extraction and Liquid-Phase Microextraction in a Single Step: Simultaneous Group Separation of Acidic and Basic Drugs

Abstract

Electromembrane extraction (EME) and liquid-phase microextraction (LPME) were combined in a single step for the first time to realize simultaneous and clear group separation of basic and acidic drugs. Using 2-nitrophenyl octyl ether as the supported liquid membrane (SLM) for EME and dihexyl ether as the SLM for LPME, basic and acidic drugs were extracted and separated simultaneously from a low pH sample by EME and LPME, respectively. After 15 min of extraction, basic drugs (citalopram and sertraline) were exhaustively extracted, whereas the recoveries for acidic drugs (ketoprofen and ibuprofen) were in the range of 76%-86%. Longer extraction time provided higher recoveries for the acidic drugs, but this somewhat deteriorated the group separation. Matrices effects from the coexisting acidic drugs/basic drugs were tested, and we observed that simultaneous EME/LPME was not affected by coexisting drugs at high concentration. This approach was further investigated from human plasma. Extraction recoveries were strongly dependent on dilution of plasma with buffer and on extraction time. Finally, this simultaneous EME/LPME approach was evaluated in combination with liquid chromatography (LC)-MS. The linearity ranges for the basic and acidic drugs were 10-600 ng/mL and 1-60 μg/mL, respectively, with R(2) > 0.997 for all analytes. The repeatability at three different levels for all analytes was less than 15%. The limits of quantification (LOQ, S/N = 10) were found to be 4.0-6.3 ng/mL and 0.6-0.9 μg/mL for basic and acidic drugs, respectively. Simultaneous EME/LPME enabled efficient group separation of basic and acidic analytes under optimum experimental conditions for both EME and LPME.

Efficient Discrimination and Removal of Phospholipids During Electromembrane Extraction from Human Plasma Samples

“…Venlafaxine and citalopram were selected to represent non-polar basic drugs (log P > 2), and benzamidine, ephedrine, and trimethoprim were selected to represent polar basic drugs (log P < 2). Venlafaxine was extracted with EME for the first time, while the other model analytes were reported previously [191,192].…”

Determination of Barbiturates in Biological Specimens by Flat Membrane-Based Liquid-Phase Microextraction and Liquid Chromatography-Mass Spectrometry

“…Hence, appropriate sample preparation is necessary and of great significance in the whole analysis process. With the development of extraction techniques, miniaturized techniques such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) have already been the current trend in sample cleanup [25,26,27,28,29,30,31]. Compared to conventional liquid-liquid extraction (LLE) and solid-phase extraction (SPE), SPME and LPME offer short extraction time and high extraction efficiency without using large volumes of organic solvent.…”

“…On the other hand, LPME, which is considered as a “green” extraction technique, has attracted widespread attention for its good purification capability, economical efficiency, and easy operation [18,28,29,30,31,34]. Until now, LPME has already been applied in the purification and enrichment steps in different biological samples [8,16,18,23,34].…”

Magnetic extractant with an Fe3O4@SiO2 core and aqueous ammonia coating for microextraction of petroleum acids

“…Nevertheless, there are some drawbacks of the LLE method including the issues caused by emulsion formation and the large consumptions of time and solvent. 9 Liquid phase microextraction (LPME), a relatively environment friendly (green) technique that employs a minimal amount of solvent, 10 has been proved to be a good solution to overcome the above problems in various samples, [11][12][13] although it has not yet been applied to the extraction of PAs in crude oils.…”