RESUMO
A simple and green method for the determination of trace bisphenol A( BPA) was established by coupling supported ionic liquid solid phase extraction to β-cyclodextrin modified ionic liquid carbon paste electrode-based electrochemical detection ( SILs-SPE-ED) . The synthesized imidazolium ionic liquid modified styrene type macroporous resin was used as adsorbent for SPE of BPA. The critical parameters that affect the extraction efficiency were optimized, including 0. 4 g of packing material quantity, 200 mL of sample solution at pH 7. 0, 5 mL of methanol as an eluent solvent, and 4. 5 mL/min of the SPE flow rate. Dynamic adsorption test showed that the maximum adsorption capacity of BPA on the SILs-SPE cartridge was 10. 1 mg/g, and the enrichment factor was 40 . The calibration curve showed a good linearity between the anodic current and the BPA concentration in the range of 1. 0×10-8-1. 0×10-6 mol/L (i. e. 2. 3-228μg/L). The detection limit was 4. 16×10-9 mol/L (equal to 0. 95 μg/L). The SILs-SPE-ED method was applied to the analysis of water and plastic samples and the results agreed well with HPLC method.
RESUMO
The effects of adsorption time, solid-liquid ratio, sample concentration, flow rate on the adsorption properties of supported ionic liquids(the N-methylimidazolium functionalized silica, SilprMin) for flavonoids were investigated. The results indicated that the adsorption equilibrium for tested compounds, genistein, luteolin and quercetin, was achieved within 30 min, the adsorption efficiencies of these three compounds were improved with the increase of solid-liquid ratio, and decreased with the increase of their concentrations. Moreover, the adsorption isotherm data of the three tested compounds were in good concordance with the Langmuir model. The saturated adsorption capacity of SilprMim for genistein, luteolin and quercetin was 47.7, 52.5 and 63.2 mg/g, respectively. Adsorption efficiency of SilprMim could reach more than 90% at a sample flow rate of 0.5～1.5 mL/min. Using methanol as eluent, the saturated desorption efficiencies of genistein, luteolin and quercetin were 86.1%, 83.3% and 84.6%, respectively. The elution order of the three tested flavonoids was genistein, luteolin and quercetin. SilprMim had strong adsorption and separation capacity for three tested flavonoids, which was hopeful to be applied in separation and purification of naturally occurring flavonoids.