Development of a biosensor for the quantitative detection of 2,4,6-trichloroanisole using screen printed electrodes

Immunoassay techniques can provide a simple, practical and inexpensive method for analysis of 2,4,6-trichloroanisole (TCA). Enzyme linked immunosorbent assay (ELISA) and electrochemical techniques were investigated with the purpose of attaining high selectivity and sensitivity. Both assays incorporated a direct format for analysis of TCA using alkaline phosphatase (AP), as the labeling species. TCA has no functional groups through which linkage of enzymes or proteins can be achieved so alternative hapten molecules were developed. Molecular recognition between TCA and the antibodies that were raised against haptens whose chemical structures were similar to the target analyte was good. This was especially true for the competition between free analyte and hapten A-AP conjugate for the protein G purified polyclonal antibodies (pAb₇₆). ELISA results using the direct format of analysis were poor when compared to the achieved results for the electrochemical sensor. A limit of detection of 1ng/ml (1ppb) was achieved for the best ELISA system while a limit of detection of 29pg/ml (29ppt) was obtained for the electrochemical sensor.