Determination of total leachable bisphenol A from polysulfone membranes based on multiple consecutive extractions.

The paper presents the development of a multiple consecutive extraction method enabling the determination of the total amount of bisphenol A (BPA) released from porous polysulfone (PS) membranes in a hemodialyzer or hemoconcentrator under simulated-use conditions. The levels of BPA were determined using solid phase extraction (SPE) coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS). We demonstrated that it was difficult to determine the total amount of BPA released from the PS membranes using a single extraction method with finite solvent volume because of the chemical equilibrium between the extraction solution and the polymer phase. Repeated extractions gave more accurate results than a single extraction for the determination of the total amount of leachables in porous membranes. A general equation was derived to fit the elution profile of BPA released during multiple consecutive extractions.