ABSTRACT
A method was developed for determination of 12 kinds of phosphate compounds in water and sediment by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupled with solid phase extraction (SPE) and ultrasonic extraction.The water samples were concentrated by HLB solid-phase extraction (SPE) column and eluted twice with ethyl acetate, ultrasonic solvent extraction for sediment samples and then repeated the operation of water samples after diluted with deionized water.The sample were separated on a ZORBAX Eclipse Plus C18 (150 mm × 2.1 mm, 3.5 μm) column by a gradient elution with 0.2% formic acid aqueous solution and methanol as the mobile phase.Ion mode analysis was monitored by high performance liquid chromatography mass spectrometer (MRM).The target compounds were quantified by external standard method.At the spiked levels (0.05, 0.1 and 0.5 μg/L), the average recoveries of 12 kinds of OPEs in water samples ranged from 66.4% to 115%, except for TMP (28.5%-47.8%) and TEHP (22.4%-73.8%).The relative standard deviation RSD (n=3) was 0.5%-9.09%, and the method quantification (MOQ) was 0.001-0.05 μg/L, However at the spiked levels of 5, 10 and 50 μg/kg, the average recoveries of 12 kinds of OPEs in sediment samples ranged from 65.4% to 120.0%, except for TMP (35.7%-44.9%) and TCEP (31.2%-48.9%).The relative standard deviation RSD (n=3) was 0.01%-9.54%, and the MOQ for sediment was 0.02-2.0 μg/kg dw.Based on the above methods, the detection and analysis of the targets in the water and sediments samples of Taihu Lake were carried out.The results showed that the concentrations of ΣOPEs were 0.1-1.7 μg/L and 8.1-420 μg/(kg dw), respectively.
ABSTRACT
A method for the simultaneous determination of 34 pesticides in sunflower oil, soybean oil and corn oil was developed. The samples were extracted and purified by a modified QuEChERS method, and then the supernatant was analyzed by on-line gel permeation chromatography-gas chromatography-mass spectrometry ( GPC-GC-MS ) . The linear range was from 0 . 01 to 0 . 2 mg/L with a good correlation coefficients ( r≥0. 9913). The average recoveries of 31 pesticides (except p,p′-DDE, p,p′-DDD, p,p′-DDT. For detail, please reference to section 3 . 6 ) ranged from 70 . 3% to 115 . 4%, 69 . 5% to 112 . 6% and 70 . 2% to 116 . 1%spiked at 0. 05 μg/g and 0. 1 μg/g with the relative standard deviations (RSDs, n=6) less than 13. 3%, 13. 5% and 12. 1% in sunflower oil, soybean oil and corn oil samples, respectively. The LODs of this method ranged from 0. 0692 to 2. 28, 0. 0559 to 2. 01 and 0. 0584 to 2. 14μg/kg (S/N=3) in sunflower oil, soybean oil and corn oil samples respectively. The convenient operation and versatility of this method are suitable for the fast screening and detection of 34 pesticide residues in sunflower oil, soybean oil and corn oil.