Determination of Bisphenol A in Food-Simulating Liquids Using LCED with a Chemically Modified Electrode

Abstract

Liquid chromatography with electrochemical detector (LC-ED), using a chemically modified electrode coated with a metalloporphyrin film, is reported for determination of bisphenol A (BPA) migration from polycarbonate baby bottles. The extraction process of the samples was performed according to regulations of the Southern Common Market (MERCOSUR), where certain food-simulating liquids [(A) distilled water, (B) acetic acid 3% V/V in distilled water, and (C) ethanol 15% V/V in distilled water] are defined along with controlled time and temperature conditions. The baseline obtained using the naked electrode showed a considerable drift which increased the detection limit. This effect was suppressed with the chemically modified electrode. A linear range up to 450 ppb along with a detection limit of 20 ppb for the amperometric detection technique was observed. The procedure described herein allowed lowering the detection limit of the method to 0.2 ppb. The value found for BPA in the food-simulating liquid is 1.2 ppb, which is below the tolerance limit for specific migration (4.8 ppm).

Release of Bisphenol A from Food Can Lining upon Heating.

“…BPA Analysis ---Unheated and heated samples were opened and the 180-ml water samples were taken, from more than one can if necessary, for analysis. To these samples, 1 µg of BPA-d 16 (Kanto Chemical Co., INC., Tokyo, Japan) was added as an internal standard. The samples were passed through a solid-phase extraction cartridge (Sep-Pak plus PS-2, Waters Ltd., U.S.A.), which was cleaned with solvents in advanced, at a rate of 5 ml/min using an automatic pump (Concentrator, Waters Co., U.S.A.).…”

“…After extraction, the cartridge was centrifuged to remove water remaining therein. BPA and BPA-d 16 in the cartridge were eluted with 9 ml of dichloromethane at 1 ml/min. At the same time, a *To whom correspondence should be addressed: Faculty of Environmental Studies, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.…”

“…: +81-95-843-1811; Fax: +81-95-843-6377; E-mail: takao@net.nagasaki-u.ac.jp trace amount of water was dehydrated with the other cartridge, which was filled with anhydrous sodium sulfate (Sep-Pak Dry, Waters Co.), mounted on the rear. The eluate was evaporated down to approximately 0.5 ml under high-purity nitrogen gas flow, and 200 µl of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA; SUPELCO, Inc., Bellefonte, Pennsylvania, U.S.A.) was added to the eluate for the silylation 18,19) of BPA and BPA-d 16 . The resultant sample was sealed and left to stand at room temperature for 1 hr to allow the reaction to proceed.…”

“…The total peak area of the m/z = 357 and 358 peaks was used for quantification of trimethylsilylated BPA (BPA-TMS), and the 368 and 369 peaks were used for quantification of BPA-d 16 -TMS. The amount of BPA in the water was calculated from the ratio between these 2 values.…”

“…[13][14][15][16][17] However, the amounts reported were highly variable due to the different situations and other factors. The purpose of this work is to investigate the relationship between the amount of BPA leached and the BPA content of the can lining, the heating temperature, and the lining material.…”