Thin-Layer and Wall-Jet Arrangement of Amperometric Detector with Boron-Doped Diamond Electrode: Comparison of Amperometric Determination of Aminobiphenyls in HPLC-ED

The performance of a microcrystalline boron-doped diamond electrode in a thin-layer and wall-jet amperometric detection cell for HPLC was compared with the spectrophotometric detection. Comparison of peak parameters of 2-, 3-, and 4-aminobiphenyl after their separation revealed satisfactory repeatabilities of signal responses for all detection modes and regarding electrochemical detection higher current densities and higher noise for the thin-layer arrangement, and a slightly wider linear dynamic range of calibration dependencies and lower quantitation limits in the 10-8 mol?L-1 concentration range for the wall-jet arrangement. This detection mode was further employed for the determination of studied aminobiphenyls in model samples of the synthetic colorant tartrazine. Using solid phase extraction for the preliminary separation and preconcentration of the analytes the limit of quantitation was lowered to nanomolar concentrations.