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Abstract: A rapid, accurate and reliable analytical method was developed for the simultaneous determination of five major anthraquinones, aloe-emodin, chrysophanol, emodin, physcion, and rhein, in radix Polygoni multiflori, a traditional Chinese herbal medicine. The method comprises a fast ultrasonic extraction with methanol and derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS) followed by capillary gas chromatographic (GC) separation. The effect of reaction time on the derivatization of anthraquinones was examined. A baseline separation of the anthraquinone and internal standard derivatives was achieved in 15min. The detection limits range from 0.22 to 0.60μg/mL for the five anthraquinones. The calibration curves are linear over the concentration range studied (from the detection limits to 40.0μg/mL) with the squares of correlation coefficients, R 2, greater than 0.998. The developed method was successfully applied to the simultaneous determination of anthraquinones in radix P. multiflori samples. The peak identification was confirmed using GC–MS. The contents of anthraquinones in radix P. multiflori samples studied were 27.41, 289.6, 64.22, 202.1, 288.6μg/g for chrysophanol, emodin, aloe-emodin, physcion, rhein, respectively. All relative standard deviations are less than 3.2%. The recoveries range from 80.2% to 119.3% for the five analytes. To the authors’ best knowledge, this is the first GC method reported for the simultaneous determination of the five anthraquinones in radix P. multiflori. [Copyright &y& Elsevier]

Abstract: A novel, simple and rapid method, termed ultrasound-assisted emulsification microextraction and solidification of floating organic droplet (UAEM–SFO) coupled to high performance capillary electrophoresis (HPCE), was developed for preconcentration and analysis of five phenolic compounds (PCs) in human urine and blood samples. The proposed method is based on microextraction of target analytes in less-toxic organic solvent under assistance of ultrasound. A micro-droplet of less-toxic organic solvent floating on the surface of liquid samples in a sealed vial can be dispersed into sample solutions under the ultrasound frequency, solidified under ice bath, collected with a medicine spatula, molten at ambient temperature, and finally subjected to HPCE analysis. The parameters of UAEM–SFO procedure including type and volume of extraction solvent, extraction temperature, time of ultrasound-assisted extraction and centrifugation, sample pH, and ionic strength were optimized. The influence parameters on HPCE resolution such as pH, concentration of running buffer, applied voltage and injection time were also investigated. This method requires only 40μL of 2-dodecanol extraction solvent and 8min of pretreatment time. The enrichment factors of analytes were in the range of 114–172 and extraction recoveries (69–86%) were obtained. Good linearity was achieved for five analytes in the range of 0.05–100μgL−1 and the correlation coefficients ranged from 0.9934 to 0.9999. The limits of detection were 0.01μgL−1for triclosan (TCS) and biophenol A (BPA), and 0.02μgL−1 for pentachlorophenol (PCP), 2,4-dichlorophenol (2,4-DCP) and 4-nonylphenol (4-NP) in urine samples, and 0.02μgL−1 for TCS and BPA, 0.04μgL−1 for PCP, 2,4-DCP and 4-NP in blood samples. The developed UAEM–SFO–HPCE method has a great potential in routine residual analysis of trace PCs in biological samples. [Copyright &y& Elsevier]

A novel graphene oxide-molecularly imprinted polymers (GO-MIPs) was prepared and applied for selective extraction and preconcentration of bis(2-ethylhexyl) phthalate (DEHP) in environmental water samples by using the dispersive solid-phase microextraction (DSPME) method. The GO-MIPs was synthesized via precipitation polymerization using GO, DEHP, methacrylic acid, and ethylene dimethacrylate as supporting materials, template molecules, functional monomer, and cross-linker, respectively. The prepared GO-MIPs were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. The GO-MIPs-DSPME conditions including type and volume of elution solvents, adsorbents amount, initial concentration of DEHP, pH and ionic strength of water samples were investigated. Under optimized conditions, the DEHP was selectively and effectively extracted in real water samples and enrichment factors of over 100-fold were achieved. Good linearity was obtained with correlation coefficients (R 2 ) over 0.999 and the detection limit (S/N = 3) was 0.92 ng mL −1 . The average recoveries of the spiked samples at three concentration levels of DEHP ranged from 82% to 92% with the relative standard deviations less than 6.7%. The results indicated that the proposed GO-MIPs-DSPME extraction protocol combined with HPLC-UV determination could be applied for selective and sensitive analysis of trace DEHP phthalate in environmental water samples. [ABSTRACT FROM AUTHOR]