Simultaneous electrophoretic concentration and separation of herbicides in beer prior to stacking capillary electrophoresis UV and liquid chromatography-mass spectrometry

Abstract

Simultaneous electrophoretic concentration and separation (SECS) was used as a simple and environmental friendly sample preparation strategy for herbicides in beer samples. An electric field was used to facilitate the separation and concentration of the analytes based on their charge from a 20 mL sample of diluted beer into two separate 20 μL aliquots of an acceptor electrolyte housed inside a micropipette. The anionic organophosphonate and cationic quaternary ammonium herbicides were concentrated in the anodic and cathodic pipette, respectively. Under optimized conditions, SECS was completed in 30 min at an applied voltage of 150 V, which provided analyte concentration factors of up to 90. After sample preparation, the SECS concentrate of cationic and anionic herbicides was analyzed by stacking CE with UV detection and also by LC-MS, respectively. The method detection limit for the diluted and undiluted sample was as low as 3 and 15 ng/mL, respectively. The method was linear over two orders of concentration with repeatability and intermediate precision of better than 5.8 and 7.0%RSD, respectively. Accuracy values were between 91.0-115.1%.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…Thus, Wuethrich et al. applied simultaneous electrophoretic concentration and separation (SECS), as environmentally friendly sample preparation strategy, for organophosphonates and quaternary ammonium herbicides determination in beer samples . After sample preparation, negatively charged organophosphonate herbicides glyphosate, glufosinate, and aminomethylphosphonic acid were analyzed by LC–MS, whereas cationic analytes, such as paraquat and diquat were detected by two‐step stacking in CE‐UV.…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2016–2018)

“…The mechanism of sweeping and MSS are opposite such that their combination is intuitive and potentially powerful. Sweeping‐MSS can be achieved when the sample and BGE are both free of pseudostationary phase and a pseudostationary phase solution is injected between sample and BGE . As with MSS, the pseudostationary phase must have an opposite charge to the analytes.…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2014–2016)

“…During this review period there were four papers on sweeping‐MSS . All articles investigated cationic analytes including quaternary ammonium herbicides , nitroimidazole drugs , and strychnosand quinolizidine alkaloids . The samples were beer, rabbit plasma, and Chinese herbal medicines.…”

“…The samples were beer, rabbit plasma, and Chinese herbal medicines. The sample preparations included protein precipitation , reflux extraction , and simultaneous electrophoretic concentration and separation (SECS) . SECS was a simple (no need for drying and reconstitution of the extracted sample) and purely electric field driven off‐line sample preparation which was based on the well‐known on‐line sample concentration technique of FASI or electrokinetic injection in CE .…”