Detection of the Antimicrobial Triclosan in Environmental Samples by Immunoassay

Abstract

A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for the detection of the antimicrobial triclosan (TCS; 2,4,4’-trichloro-2’-hydroxydiphenyl ether) was developed. Novel immunizing haptens were synthesized by derivatizing at the 4-Cl position of the TCS molecule. Compounds derived from substitutions at 4’-Cl and that replaced the 2’–OH with a –Cl were designed as unique coating antigen haptens. Polyclonal rabbit antisera were screened against the coating antigen library in order to identify combinations of immunoreagents resulting in the most sensitive assays. The most sensitive assay identified was one utilizing antiserum #1155 and a heterologous competitive hapten where the 2’–OH group was substituted with a Cl. An IC50 value and the detection range for TCS in assay buffer were 1.19 and 0.21–6.71 μg/L, respectively. The assay was selective for TCS, providing low cross-reactivity (< 5%) to the major metabolites of TCS and to brominated diphenyl ether-47. A second assay utilizing a competitive hapten containing Br instead of Cl substitutions was broadly selective for both brominated and chlorinated diphenylethers. Using the most sensitive assay combination, TCS concentrations were measured in water samples following dilution. Biosolid samples were analyzed following dilution of a simple solvent extract. The immunoassay results were similar to those determined by LC-MS/MS. This immunoassay can be used as a rapid and convenient tool to screen for human and environmental exposure.

Benefits of basic research from the Superfund Research Program

“…Building off of the SRP-funded work, more than 40 immunoassays for pesticides, pesticide metabolites, and other environmental contaminants have been developed (157). These immunoassays, which were originally developed with SRP funding, have since been developed with a variety of funding sources to detect a large number of chemicals including immunoassays to detect polybrominated diphenyl ether BDE-47 (158), the insecticide fipronil (159), and the antimicrobials triclocarban (160) and triclosan (161).…”

Sustainable exposure prevention through innovative detection and remediation technologies from the NIEHS Superfund Research Program

“…In addition, a sensitive, competitive enzyme linked immunosorbent assay (ELISA) is being developed for the detection of the antimicrobial triclosan (Table 1M). This bioassay is a rapid and convenient tool to screen for human and environmental exposure (17). Lastly, an innovative assay to map protein targets of environmental chemicals is another approach for rapid toxicity screening (Table 1N).…”

An Immunoaffinity Purification Method for the Simultaneous Analysis of Triclocarban and Triclosan in Foodstuffs by Liquid Chromatography Tandem Mass Spectrometry

“…An immunoaffinity column (IAC), using analyte-specific antibodies as sorbent, has been proven to be a selective method for isolating, purifying, and concentrating target analytes from complex matrices. , Antibodies are the most important reagents in preparing an IAC, and there is a direct correlation between the performance of an antibody and the potential use of an IAC . However, only a few studies have been concerned with polyclonal antibodies (pAbs) of TCC or TCS, whereby the respective antibodies were used to develop indirect enzyme-linked immunosorbent assays for the individual detection of TCC or TCS in environmental or biosamples. None of the cleanup methods hitherto used for the determination of TCC and TCS in foodstuffs has been selective.…”