| More and more attention has been paid to the effects of organic pollutants on human health and the environment. For instance, phthalate esters and triazines are harmful to human health which may lead to cancer, deformity, mutation, and even disturb human endocrine. The analysis of organic pollutants is difficult because of their low concentrations in environmental samples and complicated matrices. Therefore, it is necessary to develop a rapid, simple, and efficient sample preparation method for organic pollutants in practical analysis. In the present work, poly(methacrylic acid-ethylene glycol dimethacrylate) monolith microextraction has been employed as the preconcentration method for organic pollutants. The proposed method has several advantages such as low consumption of sample and solvent, rapidness, and low detection limits. It is proper for the analysis of trace organic pollutants in real samples.A method of poly(methacrylic acid-co-ethylene glycol dimethacrylate) (poly(MAA-EGDMA)) monolith microextraction coupled with high performance liquid chromatography (HPLC) has been successfully used to determine four phthalate esters in cosmetics, i.e., dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), dicyclohexyl phthalate (DCHP), and di-n-octyl phthalate (DOP). The experimental parameters have been investigated and optimized as follows. The mobile phase is methanol and H2O (95:5, V/V) at a flow-rate of 1.0 mL/min. The column temperature is 35℃. The preferential detection and reference wavelengths are 228 nm and 360 nm, respectively. The width of slit is 16 nm and the injection volume is 5μL. The factors affecting the extraction efficiency have also been optimized. Firstly, 0.2 mL of methanol and 0.5 mL Na2HPO4 (pH 4.0) are introduced into the syringe and expelled to pass through the monolithic capillary tube. After that,1.0 mL sample solution is ejected at 0.2 mL/min in the same way. After the capillary has been washed, ethanol is injected to the monolithic capillary at 0.086 mL/min for 1 min to elute the sample from the capillary and the eluate is collected into a vial for HPLC determinations.26 min is enough for the whole analysis of phthalate esters including the polymer monolith microextraction and HPLC procedures. In order to evaluate the method, linear range, precision, limits of detection (LOD), and limits of quantification (LOQ) have been investigated. The linear range is determined as 3-5000 ng/mL with the intra-day and inter-day precisions of 1.4-3.2% and 5.8-7.7%, respectively. Moreover, this method has been applied to the determination of the target phthalate esters in 2 lacquer remover samples and 6 perfume samples, giving recoveries from 81.2% to 108.8%.The polymer monolith microextraction method coupled with HPLC-DAD has also been applied to the determination of six triazines, cyanazine, simazine, atrazine, prometon, ametryn, and prometryn in cereals samples. Sample flow rate, sample volume, sample pH, and eluent flow rate have been investigated and optimized in detail with respect to extraction efficiency. Under the optimized condition, the linear range is 10-5000 ng/mL. The intra-day and inter-day precisions of the present method are in the range of 1.4-4.3% and 2.1-5.5%. Finally, the method has been used to determine the triazines in kaoliang, maize, millet, oat, and rice with a recovery range of 73.4%-107.2%. |
PDF Full Text Request