Elimination of matrix effects in the determination of bisphenol A in milk by solid-phase microextraction–high-performance liquid chromatography

Abstract

Solid-phase microextraction coupled to high-performance liquid chromatography (SPME–HPLC) with fluorescence detection was employed to determine bisphenol A (BPA) in milk samples. The potential influence of the milk matrix on the determination of BPA by SPME–HPLC were investigated. Optimal conditions to eliminate any matrix effects were as follows: milk samples were deproteinized with trichloroacetic acid, diluted 20-fold with BPA-free Ultrapure water, dissolved in methanol, the precipitated protein was filtered out, rinsed with methanol and evaporated to remove the methanol. Then, a 40.0-ml solution was used for SPME extraction and HPLC analysis. Satisfactory recoveries (milk: 93.1–101%; soybean milk: 93.9–102%) were achieved. The proposed method was successfully applied to real samples, BPA being detected within the range 1.6–2.6 ng ml⁻¹ in four brands of commercial milk but not in soybean milk.

Keywords:

• bisphenol A
• matrix effect
• milk
• solid-phase microextraction–high-performance liquid chromatography

Acknowledgements

The authors thank the National Natural Science Foundation of China (NSFC) Fund (No. 20305008), the Huo Ying Dong Science Fund of China (No. 104038) and the Central Teacher Plan in Lanzhou University for support.