Analytical chemistry, 16 October 2018, Vol.90(20), pp.12172-12179
A multiplex-on-bead-isotope-dimethyl-labeling method was developed for the quantitative analysis of sulfonamides (SAs) in environmental water samples by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). In this method, five samples could be labeled in parallel with different isotope reagents and quantified in a single LC-HRMS analysis. Magnetic solid-phase extraction (MSPE) was employed in the sample preparation to concentrate the trace-level analytes by using lab-synthesized magnetic carbon nanospheres (MCNSs). After the analytes were captured on the MCNSs, the isotope labeling was performed directly by dispersing the MCNSs in the reaction buffer (on-bead labeling). The experimental conditions for MSPE and labeling were systematically investigated. For the tested 12 SAs, a labeling efficiency of over 99% could be achieved within 20 min. The LC-HRMS separation, including equilibration, could be achieved in 6 min. By combining MSPE (enriched 200-fold), multiplex on-bead dimethyl labeling, and LC-HRMS, all the tested SAs could be reliably quantified with limits of detection (LODs) of 0.1-5 ng/L. This method was verified using fortified pond water spiked with 12 SAs (0.01-5 μg/L), and accuracies of 81-106% were achieved with good reproducibility (RSD 〈 10%, n = 3), which confirmed its applicability in real-sample analysis. With this method, ice samples collected at the estuary of the Daliao River in northeast China were analyzed; nine SAs (sulfanilamide, sulfapyridine, sulfamethazine, sulfamethizole, sulfachloropyridazine, sulfamethoxypyridazine, sulfameter, sulfathiazole, and sulfisoxazole) were detected at concentrations of 0-85 ng/L, and the total concentrations were in the range of 185-402 ng/L with a median value of 274 ng/L.
Isotopes ; Chromatography ; Mass Spectrometry ; Mass Spectrometry ; Liquid Chromatography ; Reagents ; Reproducibility ; Analytical Chemistry ; Sulfisoxazole ; Estuaries ; Sulfonamides ; Liquid Chromatography ; Mass Spectrometry ; Rivers ; Sulfamethizole ; Water Analysis ; Labelling ; Sulfanilamide ; Sulfameter ; Quantitative Analysis ; Solid Phases ; Sample Preparation ; Reagents ; Sulfapyridine ; Estuarine Environments ; Sulfamethazine ; High Resolution ; Spectroscopy ; Multiplexing ; Mass Spectroscopy ; Dimethyl ; Sulfathiazole ; Sulfamethoxypyridazine ; Liquid Chromatography ; Nanospheres ; Water Sampling ; Sulfonamides ; Estuaries;
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