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.