Determination of Selenium in Water by Vortex-Assisted Cloud-Point Extraction Combination with Fluorescence Detection

A simple vortex-assisted cloud-point extraction(VA-CPE)method combined with the fluorescence(FL)strategy was developed to extract and determine inorganic Se(IV)in environmental water.Toluene was used as an extraction reagent,and Se(VI)was reduced to Se(IV)by subjecting its solution in 4 mol/L HCl to microwave heating for generating a yellow piazselenol complex using 3,3'-diaminobenzidine(DAB)and Se(IV).The concentration of the complex exhibited an excellent linear relation with the FL at 560 nm with an excitation wavelength of 420 nm.In addition,the effects of the toluene volume,pH,and VA-CPE parameters were investigated and the interference from coexisting ions was also studied.This method was successfully applied to determine the concentration selenium in environmental water samples with a detection limit of 0.05μg/L in the line range from 0.50μg/L to 50.00μg/L.

Determination of synthetic phenolic antioxidants in essence perfume by high performance liquid chromatography with vortex-assisted,cloud-point extraction using AEO-9

This study aimed to establish a rapid analytical method to determine antioxidants in essence. A simple,efficient and practical, vortex-assisted, cloud-point extraction（VACPE） procedure is proposed for extracting and pre-concentrating four different of synthetic phenolic antioxidants（SPAs）, propyl gallate（PG）, tert-butylhydroquinone（TBHQ）, butylated hydroxyanisole（BHA）, butylated hydroxytoluene（BHT） in essence prior to high performance liquid chromatography（HPLC） analysis. The non-ionic surfactant, fatty alcohol polyoxyethylene ether-9（AEO-9）, was used as extractant and vortex-mixing was utilized to reduce extraction time and improve extraction efficiency. The effective parameters of the extraction process, such as volume of extraction solvent, pH, vortex-mixing time, equilibration temperature and time, were optimized. Under the optimum conditions, the linear range of PG, TBHQ,BHA and BHT was 8.0–800 ng/mL. All correlation coefficients of the calibration curves were higher than0.996 and relative standard deviations（RSD, n = 5） were 2.36%–5.46%. The proposed method was successfully applied to the extraction and determination of antioxidants in essence samples with satisfactory relative recoveries of 89.4%–103.5%. The results confirmed the SPAs of essence could be effectively monitored by this method and also established good reference criteria for essence.