Sensitive determination of methadone in human serum and urine by dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet followed by HPLC–UV

Abstract

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the extraction of methadone and determination by high-performance liquid chromatography with UV detection. In this method, no microsyringe or fiber is required to support the organic microdrop due to the usage of an organic solvent with a low density and appropriate melting point. Furthermore, the extractant droplet can be collected easily by solidifying it at low temperature. 1-Undecanol and methanol were chosen as extraction and disperser solvents, respectively. Parameters that influence extraction efficiency, i.e. volumes of extracting and dispersing solvents, pH, and salt effect, were optimized by using response surface methodology. Under optimal conditions, enrichment factor for methadone was 134 and 160 in serum and urine samples, respectively. The limit of detection was 3.34 ng/mmL in serum and 1.67 ng/mL in urine samples. Compared with the traditional dispersive liquid-liquid microextraction, the proposed method obtained lower limit of detection. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high-density and toxic solvents of traditional dispersive liquid-liquid microextraction method. The proposed method was successfully applied to the determination of methadone in serum and urine samples of an addicted individual under methadone therapy.

Simultaneous extraction and quantification of albendazole and triclabendazole using vortex‐assisted hollow‐fiber liquid‐phase microextraction combined with high‐performance liquid chromatography

“…In comparison with other liquid‐phase extraction methods, LPME methods have the advantages of ease of operation, low cost, low consumption of organic solvents, and the possibility of obtaining a high enrichment factor. So far, different modes of LPME including dispersive liquid–liquid microextraction, single drop microextraction, solidified floating organic drop microextraction, vortex‐assisted emulsification microextraction, ultrasound‐assisted emulsification microextraction, and hollow‐fiber liquid‐phase microextraction (HF‐LPME) have been developed and used for the extraction of various compounds. Among these LPME methods, only ultrasound‐assisted emulsification microextraction, vortex‐assisted surfactant‐enhanced emulsification microextraction, ultrasound‐assisted surfactant‐enhanced emulsification microextraction, and surfactant‐solvent‐based quaternary component emulsification microextraction have been used for extraction of benzimidazole compounds.…”

Dispersive liquid‐liquid microextraction based on the solidification of floating organic droplets for preconcentration of amino acids in human plasma samples

“…The concentration of analytes in plasma samples is shown in Table . Also, the relative recovery (RR%) is defined as the following equation: where C found , C real , and C added are the concentrations of the analyte after addition of known amount of standard in the real sample, the concentration of an analyte in the real sample and the concentration of known amount of standard that was spiked to the real sample, respectively . The relative recoveries of the 19 amino acids ranged from 81 to 103%, with RSDs less than 4.2%.…”

Effervescent tablet‐assisted demulsified dispersive liquid–liquid microextraction based on solidification of floating organic droplet for determination of methadone in water and biological samples prior to GC‐flame ionization and GC‐MS

“…This method was originally based on the rapid injection of a water-immiscible organic solvent and a water-miscible disperser solvent, into the aqueous sample [13]. The main disadvantage of the initial mode of DLLME was the use of toxic solvents with higher densities than the water along with dispersive solvents [26]. Therefore, trends in DLLME have been introduced for reducing the volume of organic solvents and replacing toxic solvents with more environmental friendly alternatives.…”