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

摘要

Solid-phase microextraction coupled to HPLC (SPME-HPLC) with fluorescence detection was employed to determine bisphenol A (BPA) in milk and soymilk samples. The potential influence of the milk matrix on the determination of BPA by SPME-HPLC was investigated. Optimal conditions to eliminate any matrix effects were found to be as follows: milk samples were deproteinized with trichloroacetic acid, diluted 20-fold with BPA-free Ultrapure water and dissolved in methanol. The precipitated protein was then 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%; soymilk: 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 in 4 brands of commercial milk but not in soymilk.