Development of in-situ produced CO2 switchable fatty acid microextraction based solidification of floating organic droplet for quantification of morin and quercetin in tea, vegetable and fruit juice samples by HPLC

An in-situ produced CO2 switchable fatty acid microextraction based on solidification of floating organic droplet (In-situ-CO2-SFA-ME-SFO) was evaluated for microextraction of two antioxidant flavonoids (morin and quercetin) in tea, fruit juice and vegetable samples prior to HPLC-UV. Medium-chain fatty acids (e.g. nonanoic acid) were investigated as switchable hydrophilicity solvents via pH adjustment. Sodium carbonate (Na2CO3) was used to solubilize immiscible fatty acid in water as well as, to provide effervescence. The addition of H2SO4 into the solution led to the in-situ chemical reaction with excess Na2CO3 which resulted in effective dispersion of fatty acid through generated CO2 and separation of phases. Subsequently, solidification of the fatty acid enabled facile separation without the need for sophisticated equipment. To optimize extraction process, the effects of some important parameters on the extraction recovery were investigated. At the optimum conditions, the limits of detection (LODs) and the limits of quantification (LOQs) were found 0.5 and 1.3 µg L−1 and 1.6 and 4.3 µg L−1 for morin and quercetin respectively. The preconcentration factors were 105 while, the relative standard deviations (RSDs %) of the method were < 3.5 % for both flavonoids. The recoveries of the analytes in tea, vegetable and fruit juice samples were in the range of 95.5 and 98.2

Equilibrium sampling through membrane based on a hollow fiber for determination of naproxen and diclofenac in sludge slurry using Taguchi orthogonal array experimental design

A three-phase hollow fiber liquid phase microextraction (HF-LPME) method was evaluated for the extraction and preconcentration of naproxen and diclofenac using a polypropylene membrane followed by analysis using HPLC or LC/MS. In this technique, the drugs were extracted into di-n-hexyl ether immobilized in the wall pores of a porous hollow fiber from 50mL of sludge slurry sample as a donor phase with pH 3, and then back-extracted into the acceptor phase located in the lumen of the hollow fiber. Experimental factors were studied in 16 trials using a Taguchi orthogonal array experimental design with an OA(16) (4(5)) matrix. The significance of these factors was investigated using analysis of variance. The extraction time was statistically demonstrated as the main factor for the extraction of naproxen and diclofenac, while ionic strength played the role of the second most important factor for HF-LPME extraction of diclofenac. The method permitted a detection limit of 0.2-0.7ngg(-1) with relative standard deviation values of 3-5%. Enrichment factors of 2,300 for naproxen and 1,400 for diclofenac were achieved. The method was applied to determine naproxen and diclofenac in sewage sludge from sewage treatment plant, Kallby (Lund, Sweden)

Determination of non-steroidal anti-inflammatory drugs in sewage sludge by direct hollow fiber supported liquid membrane extraction and liquid chromatography-mass spectrometry

In this study, a three-phase hollow fiber liquid-phase microextraction (HF-LPME) method combined with liquid chromatography-mass spectrometry was developed for direct determination of four non-steroidal anti-inflammatory drugs (ketoprofen, naproxen, diclofenac and ibuprofen) in sewage sludge. The drugs were extracted from non-spiked and spiked slurry samples with different amounts of sludge into an organic phase and then back-extracted into an aqueous phase held in the lumen of the hollow fiber. High enrichment factors ranging from 2761 to 3254 in pure water were achieved. In sludge samples, repeatability and inter-clay precision were tested with relative standard deviation values between 10-18% and 7-15%, respectively. Average concentrations of 29 +/- 9, 138 +/- 2, 39 +/- 5 and 122 +/- 7 ng/g were determined in dried sludge from Kallby sewage treatment plant (Sweden) for ketoprofen, naproxen, diclofenac and ibuprofen, respectively. (C) 2010 Elsevier B.V. All rights reserved