•Single “click” produced silica sorbent with alkyl and carboxyl groups (silica-WCX).•The ratio of the two groups could be tuned exactly by varying the reactant ratio.•In MSPD, silica-WCX exhibited better performance than commercial sorbents tested.•β-Agonists in the porcine liver were determinate by MSPD-HPLC/UV.A single “click” strategy is proposed for the preparation of a reversed-phase/weak cation-exchange mixed-mode silica-based sorbent (silica-WCX). Upon this strategy, both 1-dodecyne and 5-hexynoic acid were simultaneously immobilized onto azide-silica in varied ratio via Cu (I)-catalyzed azide-alkyne cycloaddition click reaction. The chemical compositions of silica-WCXs were characterized by elemental analysis, acid–base titration and Fourier transform-infrared spectroscopy. The results indicated that the actual mole ratio of n-dodecyl to carboxylic group on the sorbent is almost the same as the reactant ratio of 1-dodecyne to 5-hexynoic acid, and the repeatability of synthesis method is good. After that, two β-agonists, clenbuterol and ractopamine, were selected as model drug residues to evaluate the applicability of silica-WCX in matrix solid-phase dispersion extraction for the determination of basic drug residues in porcine liver by HPLC/UV. In comparison with some commercial sorbents, silica-WCX exhibited higher recoveries and better purification capability. Under the optimized conditions, linearity ranges were between 0.04 and 8.0 μg/g for both analytes with coefficients of determination (R2) higher than 0.9997. The average recoveries at three spiked levels ranged from 92.5% to 105.0% with RSDs less than 6.6%.

A mixed-mode silica-based sorbent (silica-WCX) with a weak cation-exchange character was prepared via Cu (I)-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction. Firstly, silica particles reacted with 3-azidopropyltriethoxysilane to produce the azide-modified silica (azide–silica). After that, the azide–silica reacted in sequence with 5-hexynoic acid and 1-dodecyne via CuAAC reaction to prepare the silica-WCX sorbent bearing both carboxyl and n-dodecyl groups. The resultant silica-WCX sorbent was characterized by Fourier transform-infrared spectroscopy and element analysis, which proved the successful immobilization of 5-hexynoic acid and 1-dodecyne on the silica surface. Then, the silica-WCX sorbent was used as a SPE sorbent for the determination of primary aromatic amines (PAAs) in water samples by high performance liquid chromatography. Several parameters affecting the extraction efficiency were optimized. Under the optimized SPE conditions, the linear ranges of the proposed method varied from 1 μg L−1 to 800 μg L−1 with correlation coefficients (R2) above 0.998 for all the analytes. The limits of detection (S/N = 3) ranged from 0.08 μg L−1 to 0.28 μg L−1. The intra-day and inter-day precision ranged from 2.7 to 7.8% and from 4.6 to 8.5%, respectively. Finally, the method was applied to the determination of the PAAs in real water samples, including tap water, lake water and printing and dyeing wastewater. The recoveries of PAAs were between 85% and 111% with relative standard deviations (RSDs) less than 7.9%, except that of 4,4′-methylenedi-o-toluidine in printing and dyeing wastewater samples.

Due to the synthetic flexibility and special enantioselectivity, chiral ionic liquids (CILs) have heightened interest and an increasing number of CILs has been designed and utilized. In this work, CIL named l-1-butyl-3-(2-propionic-1-ether) imidazolium bromide ([BAlaIM]Br) derived from natural amino acids was synthesized, with chiral center at cation moiety. Chiral stationary phases for gas chromatography were then prepared by mixing the CIL with polymeric ionic liquid ([PSOMIM][NTf2], homemade) at different ratios (4:1, 2:1, and 1:1). The column efficiency was measured to be about 3,200 plates m−1 (8 m × 0.25 mm i.d.) when the content of [BAlaIM]Br was 50 % (mass percent) in the mixed stationary phase. All columns were coated via the static coating method using 0.30 % (w/v) of stationary phases dissolved in methanol. The results showed that the CIL contributed to the selectivity of stationary phase toward positional isomers dichlorobenzenes, methylnaphthalenes and pinenes, etc. Meanwhile, [BAlaIM]Br showed better selectivity for enantiomers such as carvones, citronellals, limonenes and camphors. The interactions between chiral selector and enantiomers were also discussed.

Due to the special performance of “dual nature” and synthetic flexibility, ionic liquids (ILs) have been an attractive research subject of stationary phases for gas chromatography (GC). In this work, a novel ionic liquid (IL) bonded polysiloxane ([PSOMIM][NTf2]) with anion of bis-trifluoromethanesulfonylimide (NTf2−) was synthesized, and another one with chloride anion ([PSOMIM][Cl]) was also prepared for the purpose of comparison. The thermo-stability of the product was evaluated by thermogravimetric (TG) test and the result indicated that [PSOMIM][NTf2] did not decompose slightly until 380 °C. Then the solvation behaviors of the ILs were characterized using solvation parameter model. Subsequently, [PSOMIM][NTf2] and [PSOMIM][Cl] were used as stationary phases to prepare capillary columns for GC, respectively. The column efficiency of [PSOMIM][NTf2] column was 4776 plates/m (k = 3.64 ± 0.08, naphthalene), and that of the other one was 3170 plates/m (k = 2.84 ± 0.11, naphthalene). The selectivity of the novel stationary phases for analytes, including Grob reagent, aromatic positional isomers was further evaluated. Furthermore, the chromatograms of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) on [PSOMIM][NTf2] column were compared with that on [PSOMIM][Cl] column. [PSOMIM][NTf2] stationary phase also exerted good selectivity for fatty acid methyl esters (FAMEs), polychlorinated biphenyls (PCBs) and aromatic amines.

A mixed-mode silica-based sorbent (silica-WCX) with a weak cation-exchange character was prepared via Cu (I)-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction. Firstly, silica particles reacted with 3-azidopropyltriethoxysilane to produce the azide-modified silica (azide–silica). After that, the azide–silica reacted in sequence with 5-hexynoic acid and 1-dodecyne via CuAAC reaction to prepare the silica-WCX sorbent bearing both carboxyl and n-dodecyl groups. The resultant silica-WCX sorbent was characterized by Fourier transform-infrared spectroscopy and element analysis, which proved the successful immobilization of 5-hexynoic acid and 1-dodecyne on the silica surface. Then, the silica-WCX sorbent was used as a SPE sorbent for the determination of primary aromatic amines (PAAs) in water samples by high performance liquid chromatography. Several parameters affecting the extraction efficiency were optimized. Under the optimized SPE conditions, the linear ranges of the proposed method varied from 1 μg L−1 to 800 μg L−1 with correlation coefficients (R2) above 0.998 for all the analytes. The limits of detection (S/N = 3) ranged from 0.08 μg L−1 to 0.28 μg L−1. The intra-day and inter-day precision ranged from 2.7 to 7.8% and from 4.6 to 8.5%, respectively. Finally, the method was applied to the determination of the PAAs in real water samples, including tap water, lake water and printing and dyeing wastewater. The recoveries of PAAs were between 85% and 111% with relative standard deviations (RSDs) less than 7.9%, except that of 4,4′-methylenedi-o-toluidine in printing and dyeing wastewater samples.