[Determination of biphenyl ether herbicides in water using HPLC with cloud-point extraction].

OBJECTIVE: To determine residues of multiple biphenyl ether herbicides simultaneously in water using high performance liquid chromatography (HPLC) with cloud-point extraction. METHODS: The residues of eight biphenyl ether herbicides (including bentazone, fomesafen, acifluorfen, aclonifen, bifenox, fluoroglycofenethy, nitrofen, oxyfluorfen) in water samples were extracted with cloud-point extraction of Triton X-114. The analytes were separated and determined using reverse phase HPLC with ultraviolet detector at 300 nm. Optimized conditions for the pretreatment of water samples and the parameters of chromatographic separation applied. RESULTS: There was a good linear correlation between the concentration and the peak area of the analytes in the range of 0.05-2.00 mg/L (r = 0.9991-0.9998). Except bentazone, the spiked recoveries of the biphenyl ether herbicides in the water samples ranged from 80.1% to 100.9%, with relative standard deviations ranging from 2.70% to 6.40%. The detection limit of the method ranged from 0.10 microg/L to 0.50 microg/L. CONCLUSION: The proposed method is simple, rapid and sensitive, and can meet the requirements of determination of multiple biphenyl ether herbicides simultaneously in natural waters.

[Simultaneous determination of monosaccharides and oligosaccharides in Lycium barbarum L. by high performance liquid chromatography].

OBJECTIVE: To develop a rapid approach of refractive index detection with high performance liquid chromatography (HPLC) for the determination of rhamnose, fructose, glucose, surose and maltose in Lycium barbarum L. METHODS: The sample was extracted with water and the analyte was separated by Zorbax Carbohydrate column with acetonitrile-water as mobile phase. RESULTS: Good linear correlations between the concentrations and the peak areas of the analyte were found, with the correlation coefficients ranging from 0.9976 to 0.9998. The spiked recovery rates ranged from 92.27% to 101.93%, with 1.85%-3.27% of relative standard deviations (n=5). The limits of detection (S/N =3) were 4-6 mg/kg. CONCLUSION: The proposed method is suitable for the determination of monosaccharide and oligosaccharide in Lycium barbarum L.