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Studies of portable immunochromatographic methods for analysis of pesticide residues

Mary Anne Nelson, University of Nebraska - Lincoln

Abstract

This work details the design, development and characterization of a portable immunoextraction method coupled to reversed-phase liquid chromatography for the analysis of herbicide residues. The method gave low limits of detection (LOD), excellent precision and reproducibility. The method was optimized to give a total analysis time of 10 min for the three model s-triazine compounds at a sample throughput of less than 5 min. The lower LOD was dependent upon sample size, and for a 2.00 mL sample was 0.3 μg/L at a S/N = 2. Good stability of the system was observed with within-day precisions of 16% and day-to-day precisions of 16%. This work also explored theoretical aspects of the coupling of these two methods. Assays and equations were developed for examining thermodynamic and kinetic properties of immunoaffinity columns. ^ A three step assay was used to determine thermodynamic and kinetic properties of antibody columns. The three steps were: (1) an initial application step in which analyze at various concentrations saturated the affinity column, (2) an elution step in which a step gradient elution buffer was applied, and (3) a regeneration step in which the antibodies were returned to the initial buffer conditions. This method allowed calculation of association equilibrium constants as well as association and dissociation rate constants for the antibody-antigen interaction in less than fifteen minutes per assay. Accurate on-column estimations of the thermodynamic and kinetic parameters of interest were shown. ^ Behavior of analytes at the interface of the antibody column and reversed-phase liquid chromatography column was investigated. An equation describing the application profile of analyte to the reversed-phase column was coupled with partitioning equations describing analyte behavior in the reversed-phase column. Comparison of various parameters illustrated the tendency of peaks to give skewed shapes with decreasing dissociation from the antibody column. Retention of analyte on the precolumn under aqueous conditions dictated the length of time required to elute the analyte, but did not have much effect on the overall peak shape. ^

Subject Area

Chemistry, Analytical

Recommended Citation

Nelson, Mary Anne, "Studies of portable immunochromatographic methods for analysis of pesticide residues" (2003). ETD collection for University of Nebraska - Lincoln. AAI3131551.
http://digitalcommons.unl.edu/dissertations/AAI3131551

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