Conventional ionic liquids possess several disadvantages, such as high viscosity, difficult sampling/retrieval, and great loss in aqueous solution, limiting their wide applications in the pretreatment field. To solve these drawbacks, we synthesized a quaternary ammonium polymeric ionic liquid (PIL) and pressed it into an effervescent tablet for developing an effervescence-enhanced dispersive solid-phase extraction method (QAP-EDSE). The pressed effervescent tablet was composed of PIL as an extractant, tartaric acid as an acidic source, NaHCO3 as an alkaline source, and water-soluble starch as a filler, respectively. Under the CO2-driven dispersion, the QAP-EDSE method integrated rapid enrichment, extraction, and dispersion into one synchronous step. Employing the one-factor-at-a-time approach, several important variables were optimized as follows: 200 mg of P[VBTHEA]Cl as sorbent, 400 mu L of acetone as elution solvent, 5 min of elution, solution pH 9.0, and 1 : 1.25 molar ratio of alkaline to acidic sources. Combining LC-DAD analysis, this proposed approach offered the limits of detection as low as 0.11-0.31 mu g L-1 and satisfactory recoveries of 81.40-102.62% for five sulfonamides (SAs) in environmental waters. The lower relative standard deviations (1.9-6.7%) evidenced the higher intraday and interday experimental precision by this method. Overall, the newly developed method is environmentally benign, time-saving, and easy to operate with low detection limit and high recovery and thus shows excellent prospects in the trace-level detection of SAs in environmental waters.

Herein, we developed an effervescent reaction-enhanced dispersive liquid–liquid microextraction method for the preconcentration/extraction of bisphenols (BPs) in milk and milky tea samples. This microextraction method was based on the utilization of acidic ionic liquid (AIL) and in situ metathesis reaction (AI-EDLM). Compared to the traditional imidazolium-based ionic liquid, AIL can not only be used as an extractant, but also as an acidic source in the effervescent reaction. Under such a case, it can avoid the use of additional acidic source and also achieve a rapid dispersion effect due to vigorous CO 2 bubbles, which simplify the experimental procedures and decrease the preparation cost of effervescent tablets. By employing the one-factor-at-a-time approach, the main parameters were optimized as follows: 400 mg of [BMIM][HSO 4 ] as extractant, 100 mg of Na 2 CO 3 as alkaline source, 400 mg of Li[NTf] 2 as the ionic-exchange reagent, 4% of NaCl, 5 min of centrifugation and 1.5 mL of ether as the elution solvent. Under optimized conditions, the limits of detection ranged from 0.12 to 0.32 μg L −1 , and the extraction recoveries for BPA, BPB, and BPAF spanned the range of 85.7–106.2% in five kinds of milk samples. Therefore, the AIL ([BMIM][HSO 4 ]) played dual roles, i.e., extractant and pH regulator, in the AI-EDLM procedures. Overall, this proposed method is simple, quick, and environment-friendly with low detection limits and high recoveries for BPs, and thus has excellent application value in the sample pretreatment field in milk and milky tea samples.

A novel adsorbent, poly(sodium 4-styrenesulfonate) modified MIL-101(Cr)-NH2, was successfully prepared. Owing to its high surface area and degree of negative surface charge, it enables effective adsorption and separation of illegal cationic dyes, such as rhodamine B, pararosaniline, and auramine O, from foodstuffs prior to high performance liquid chromatography analysis. Under optimised conditions, good linearity was obtained over 1.0-80.0 or 1.0-120 ng mL-1 with a correlation coefficient (R2) > 0.999. Limits of detection and limits of quantification of the three dyes were 0.28-0.65 and 0.94-2.13 μg kg-1, respectively. The recoveries of the three dyes in shrimp powder, chili powder, tofu sheets, and tomato sauce were in the range of 86.8-119.3%, suggesting that the developed method is a promising tool for accurate quantification of the three dyes at trace levels in foodstuffs.

The properties of anilinonaphthalene-8-sulfonic acid (ANS) as the fluorescent probe of surface active agent have been studied. The micellar assemblies of ANS-Brij35 has first been used as kinetic indicator of fluorescence. A new method using flow injection analysis (FIA) and fiber optic to determine iron(I) has been developed based upon the fluorescence quenching of ANS-Brij35 by the oxidation of hydrogen peroxide, in which the iron(III) is an effective catalyst. The linear calibration curve of iron(I) is obtained in the range of 5 similar to 300 ng/mL. The limit of detection is 2 ng/mL and the absolute detection limit is 0.2 ng. The relative standard deviation is 0.27%(n=11) at the level of 20 ng/mL iron(III). This method has been applied to the determination of iron in human hair, aluminum and aluminum alloy without pre-separation.