Solid-phase extraction coupled with dispersive liquidâliquid microextraction for determination of enrofloxacin in chicken meat

Solid-phase extraction combined with dispersive liquid–liquid microextraction has been developed as a new approach for the extraction of enrofloxacin in chicken meat prior to high performance liquid chromatography with UV detection. In the SPE-DLLME, enrofloxacin was first extracted from chicken meat into the mixture of 10 mL acetonitrile acidified with formic acid buffer (pH=4) and 10 mL EDTEA-McIlvaine buffer (0.1 M) and 20 mL n-hexane as an extracting phase by using ultrasound-assisted extraction. Then, the extract by ultrasound-assisted extraction was used for solid-phase extraction. After clean-up, enrofloxacin was preconcentrated by using DLLME technique. Thus, 1.5 mL methanol extract (disperser solvent) and 200 µL chloroform (extraction solvent) were added to 5.0 mL ultrapure water and a DLLME technique was applied. Under the optimum conditions, the linearity of the method was in the range from 10 to 500 µg kg-1 with the correlation coefficient (r2) of 0.9972. The method detection limit was 5.0 µg kg-1. The proposed method has been successfully applied to the analysis of the enrofloxacin in chicken meat, and a satisfactory result was obtained

Application of Ultrasound-Assisted Emulsification Microextraction Based on Applying Low Density Organic Solvents to the Extraction and Determination of Mononitrotoluenes in Water Samples

In this study, simple and efficient ultrasound-assisted emulsification microextraction (USAEME) based on applying low density organic solvents combined with gas chromatography-flame ionization detector (GC-FID) was developed for the preconcentration and determination of mononitrotoluenes (MNTs) in water samples. In this method, the fine droplets of toluene were formed and dispersed in the sample with the help of ultrasonic waves which accelerated the formation of the fine cloudy solution without using disperser solvents. Several factors influencing the extraction efficiency such as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time were investigated and optimized. Using optimum extraction conditions, dynamic linear ranges of 0.5-500 µg L -1 , and limit of detections (LOD) of 0.3 µg L -1 were obtained for o-nitrotoluene, m-nitrotoluene and p-nitrotoluene. Finally, the method was successfully applied to the extraction and determination of MNTs in the water samples in the range of micrograms per liter with relative standard deviations (RSD) < 12%

Homogeneous liquid-liquid microextraction via flotation assistance for determination of trace amounts of manganese prior to inductively coupled plasma-mass spectrometry

86-92In the present study, homogeneous liquid-liquid microextraction via flotation assistance method is described for preconcentration of trace amounts of Mn(II). 1-(2-pyridylazo)-2-naphthol (PAN) is used as a ligand. The enriched analyte in the floated organic phase has been determined by inductively coupled plasma-mass spectrometry (ICP-MS). In this work, low density organic solvent is used and there is no need of centrifugation. Several factors influencing the microextraction efficiency, such as pH, the amount of chelating agent, nature and volume of extraction and homogeneous solvents have been investigated and optimized. Under the optimum conditions, the linear dynamic range is 1.0-500.0 ng L-1 with a correlation coefficient of 0.9998 and the detection limit of 0.1 ng L-1. The proposed method has been successfully applied for separation and determination of manganese in different water samples

A NOVEL METHOD FOR THE DETERMINATION OF TRACE THORIUM BY DISPERSIVE LIQUID-LIQUID MICROEXTRACTION BASED ON SOLIDIFICATION OF FLOATING ORGANIC DROP

In this study, dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was used for the preconcentration and determination of thorium in the water samples. In this method, acetone and 1-undecanol were used as disperser and extraction solvents, respectively, and the ligand 1-(2-thenoyl)-3,3,3-trifluoracetone reagent (TTA) and Aliquat 336 was used as a chelating agent and an ion-paring reagent, for the extraction of thorium, respectively. Inductively coupled plasma-optical emission spectrometry was applied for the quantitation of the analyte after preconcentration. The effect of various factors, such as the extraction and disperser solvent, sample pH, concentration of TTA and concentration of aliquat336 were investigated. Under the optimum conditions, the calibration graph was linear within the thorium content range of 1.0-250 µg L-1 with a detection limit of 0.2 µg L-1. The method was also successfully applied for the determination of thorium in the different water samples

Polyaniline/Graphene Nanocomposite as a Promising Sorbent for Dispersive Solid Phase Extraction of Avermectins from Citrus Fruit Juice

A solid phase extraction sorbent based on polyaniline/graphene nanocomposite is presented. The structure and morphology of synthesized nanocomposite were investigated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction and thermal gravimetric analysis. The dispersive solid phase extraction was employed to the isolation and preconcentration of avermectins insecticide (mixture of B1a and B1b). The extraction procedure was investigated by high performance liquid chromatography-UV detection. The sorbent demonstrated a favorable analytical performance for avermectins detection with reasonable linear ranges (1.5-1000 μg L-1 and 5.0-1000 μg L-1 for B1a and B1b in order) and acceptable detection limits (0.5 μg L-1 for B1a and 2.5 μg L-1 for B1b) under optimized conditions. The extraction efficiency of polyaniline/graphene nanocomposite in the extraction of avermectins was compared with graphene, polyaniline, carbon nanotube and C18 sorbents. Moreover, the applicability of proposed method was assessed for the extraction of analyte from citrus fruit juice

Selective Dispersive Solid Phase Extraction of Ser-traline Using Surface Molecularly Imprinted Polymer Grafted on SiO2/Graphene Oxide

A surface molecularly imprinted dispersive solid phase extraction coupled with liquid chromatography–ultraviolet detection is proposed as a selective and fast clean-up technique for the determination of sertraline in biological sample. Surface sertraline-molecular imprinted polymer was grafted and synthesized on the SiO2/graphene oxide surface. Firstly SiO2 was coated on synthesized graphene oxide sheet using sol-gel technique. Prior to polymerization, the vinyl group was incorporated on to the surface of SiO2/graphene oxide to direct selective polymerization on the surface. Methacrylic acid, ethylene glycol dimethacrylate and ethanol were used as monomer, cross-linker and progen, respectively. Non-imprinted polymer was also prepared for comparing purposes. The properties of the molecular imprinted polymer were characterized using field emission-scanning electron microscopy and Fourier transform infrared spectroscopy methods. The surface molecular imprinted polymer was utilized as an adsorbent of dispersive solid phase extraction for separation and preconcentration of sertraline. The effects of the different parameters influencing the extraction efficiency, such as sample pH were investigated and optimized. The specificity of the molecular imprinted polymer over the non-imprinted polymer was examined in absence and presence of competitive drugs. Sertraline calibration curve showed linearity in the ranges 1–500 µg L-1. The limits of detection and quantification under optimized conditions were obtained 0.2 and 0.5 µg L-1. The within-day and between-day relative standard deviations (n=3) were 4.3 and 7.1%, respectively. Furthermore, the relative recoveries for spiked biological samples were above 92%