Determination of Bisphenols in Water Samples by HPLC after Preconcentration with ultiwalled Carbon Nanotubes
A sensitive and selective column adsorption method is proposed for the preconcentration and determination of bisphenols (BPs), namely bisphenol A (BPA), bisphenol E (BPE) and bisphenol F (BPF). BPs were preconcentrated on multiwalled carbon nanotubes (MWCNTs) as an adsorbent and then determined by high performance liquid chromatography (HPLC). Several parameters on the recovery of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 4 using 150 mL of validation solution containing 1.5 μg of BPs and 5 mL of methanol as an eluent. Recoveries of BPA, BPE and BPF were 71.2±1.3, 93.0±4.8 and 98.5±4.0% respectively at 95% confidence level under optimum conditions. Relative standard deviations for seven determinations were 1.9–5.2%. The maximum preconcentration factor was 180 for BPs when 900 mL of sample solution volume was used. The linear range of
calibration curve was 5 to 40,000 ng mL–1 with correlation coefficients of 0.995 (BPA), 0.990 (BPE) and 0.997 (BPF). The detection limits (3S/N) were 0.5 ng mL–1 for all BPs. The proposed method was successfully applied to the determination of BPs in leaching water from plastic bottle with high precision and accuracy.