Abstract.
This paper describes the development of two different capillary-based heterogeneous competitive flow immunoassay formats (capillary flow injection immunoassay (CFIIA) and capillary sequential injection immunoassay (CSIIA)) for the determination of 2,4,6-trichlorophenol (2,4,6-TCP). The assays are based on the competition between the analyte and an analyte derivative labelled with the enzyme β-galactosidase, for an anti-TCP antibody, followed by the injection of the mixture at equilibrium into a flow stream, where separation between the fractions bound and unbound to the antibody is performed in a glass capillary containing immobilised protein A. The antibody-tracer fraction retained inside the protein A capillary was measured by injection of 4-aminophenyl-β-D-galactoside (4-APG), followed by amperometric detection of the enzymatically generated 4-aminophenol (4-AP), leading to a negative correlation between the signal and the analyte concentration.
The two immunoassay formats were compared in terms of sensitivity and speed, giving IC50 values of 1.41±0.03 and 1.64±0.07 µg L–1, detection limits of 0.2 and 0.4 µg L–1, and sample throughputs of 6 and 4 h–1 for the CFIIA and CSIIA system, respectively.
The influence of different interfering chlorophenolic compounds in the assay was minor, with only one exception (i.e. 2,4-dichlorophenol). In addition, different water matrices were tested (surface, tap, and rain water), showing that the matrix influence was negligible, except for rainwater, which resulted in a 30% increase in sensitivity. As a conclusion, the assay is suitable for the fast screening of TCP present at low concentration levels in water samples.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Electronic Publication
Rights and permissions
About this article
Cite this article
Nistor, C., Emnéus, J. A capillary-based amperometric flow immunoassay for 2,4,6-trichlorophenol. Anal Bioanal Chem 375, 125–132 (2003). https://doi.org/10.1007/s00216-002-1631-1
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s00216-002-1631-1