Comparison of multianalyte immunosensor formats for on-line determination of organic compounds

Studies leading to the development of multianalyte immunosensing approaches are presented herein. Competitive capture formats are developed for carbar yl, atrazine, and irgarol 1051 as target compounds. Three proposals have be en tested: sequential, additive, and simultaneous formats. For individual d eterminations, the best format is the sequential mode; the additive mode is useful only for qualitative analyses; and the simultaneous mode is prefera ble for screening purposes. The proposed systems show to be advantageous ov er single-analyte sensors and other multianalyte approaches. In all cases, the sensitivity reached (limit of detection) is high enough for the analysi s of samples containing levels of each pesticide lower than 0.1 mug/L, and sensor reusability is very good (> 600 determinations). The applicability o f the multianalyte immunosensors to on-line pollution surveillance in natur al waters, as well as their advantages and limitations, is discussed.