Amperometric determination of aminobiphenyls using HPLC-ED with boron-doped diamond electrode

Amino derivatives of biphenyl have been proven to be genotoxic and/or carcinogenic, thus they are widely monitored in the environment as well as in biological liquids. This study was devoted to HPLC determination of 2-aminobiphenyl, 3-aminobiphenyl, and 4-aminobiphenyl in model drinking and river water samples using amperometric detection in a thin layer cell with boron doped diamond thin film electrode. Satisfactory separation of studied analytes was achieved at a ChiraDex column (Merck, Germany) with chemically bonded β-cyclodextrin in a mobile phase aqueous buffer/acetonitrile/methanol (40/30/30, v/v/v) with total separation time of six minutes. The highest detector response with satisfactory repeatability (relative standard deviation < 2.9% for all aminobiphenyls) was obtained using 0.01 mol L^-1 acetate buffer at pH 5.0 as an aqueous component of the mobile phase. For direct determination of aminobiphenyls in drinking and river water model samples limits of quantitation ca. 4 × 10^-7 mol L^-1 were achieved. Applying off-line solid phase extraction using Lichrolut EN (Merck, Germany) cartridges and elution by diethyl ether, limits of quantitation were lowered down to the 10^-9 mol L^-1 concentration range.