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 carbaryl, atrazine, and irgarol 1051 as target compounds. Three proposals have been tested: sequential, additive, and simultaneous formats. For individual determinations, the best format is the sequential mode; the additive mode is useful only for qualitative analyses; and the simultaneous mode is preferable for screening purposes. The proposed systems show to be advantageous over single-analyte sensors and other multianalyte approaches. In all cases, the sensitivity reached (limit of detection) is high enough for the analysis of samples containing levels of each pesticide lower than 0.1 microg/L, and sensor reusability is very good (>600 determinations). The applicability of the multianalyte immunosensors to on-line pollution surveillance in natural waters, as well as their advantages and limitations, is discussed.