Solid-phase extraction combined with a spectrophotometric method for determination of Bisphenol-A in water samples using magnetic molecularly imprinted polymer

A selective, rapid and simple method based on magnetic molecularly imprinted polymer (MMIP) as adsorbent was developed for the extraction, preconcentration, and determination of bisphenol A (PBA) in water samples. The adsorption experiments showed that the adsorption capacity of MMIP for BPA was much higher than magnetic molecular non imprinted polymers (MNIP). The MMIP exhibited an excellent selectivity towards BPA over other interfering phenols. In addition, it was successfully applied as an adsorbent in solid-phase extraction (SPE) coupled to a spectrophotometric method. Various parameters affecting the SPE of BPA by the MMIP were investigated, such as the elution solution, the amount of MMIP, and the extraction time. The spectrophotometric method is based on the optimization of the coupling reaction between BPA and a diazo compound to produce a yellow-colored product that absorbs at the wavelength of 446 nm. A linear response for the determination of BPA was achieved in the concentration range of 0.1–3.4 µg mL−1 of BPA. The limit of detection and limit of quantification for BPA were 0.03 µg mL−1 and 0.1 µg mL−1, respectively. The developed procedure was successfully applied for BPA determination in spiked tap, mineral, and waste waters samples with satisfactory recoveries. A preconcentration factor of 200 was achieved by this method allowing the determination of 0.0025 µg mL−1 BPA in water samples. Furthermore, the developed MMIP showed good reproducibility and stability for BPA detection.