ABSTRACT
A method of metal organic nanotubes-based dispersive solid phase extraction-gas chromatography-tandem mass spectrometry was developed for sensitive analysis of polychlorinated biphenyls in environmental water samples.Related important factors influencing enrichment efficiency, such as ionic strength, extraction time and amount of adsorbent, were investigated.Response surface methodology was used to optimize these factors in detail.Under the optimal conditions such as 4.92% (w/V) NaCl, 4.5 min of extraction time, 62.5 mg of adsorbent, and n-hexane as desorption solvent, wide linearity (2-1000 ng/L or 5-1000 ng/L), and low limits of detection (0.26-0.82 ng/L) were achieved.The intra-day and inter-day relative standard deviations were 0.8%-5.5% (200 ng/L, n=6)and 2.7%-7.4% (200 ng/L, n=6), respectively.Finally, this method was successfully applied to the sensitive analysis of 6 kinds of PCBs in environmental water samples, with satisfactory recoveries of 78.9%-113.3%.
ABSTRACT
A novel, simple and highly sensitive method was developed for the rapid analysis of phenolic antioxidants at trace level in edible oils. It was based on dispersive liquid-liquid microextraction ( DLLME ) and gas chromatography-mass/mass spectrometry ( GC-MS/MS) . Related important factors that may influence enrichment efficiency, such as type and volume of extraction solvent, type and volume of dispersive solvent, and extraction time were investigated and optimized in detail. The optimum conditions were as follows:a quick injection of 500 μL mixed solution ( methanol:acetonitrile=1:1 , V/V ) into 1 . 0 g oil sample with 3 mL n-hexane for 10 s of extraction time. Under the optimal conditions, the linearity (10-2000 ng/g), limits of detection (1. 5-2. 4 ng/g) and relative standard deviations (4. 0%-8. 3%) was obtained. The proposed method was applied for the analysis of 4 edible oil samples. Some of phenolic antioxidants were detected in three of them, and the recoveries of spiked samples were in the range of 81. 9%-118%.