Development of a Panel of Immunoassays for Monitoring DDT, Its Metabolites, and Analogues in Food and Environmental Matrices

Abstract

A panel of antisera was prepared using analogues and derivatives of metabolites of the organochlorine insecticide, p,p′-DDT as haptens. The assays developed exhibited differing cross-reactions for different DDT analogues and metabolites, and the choice of hapten for the detecting enzyme conjugate had almost as much effect on assay specificity and sensitivity as the structure of the hapten used for antibody production. Those assays developed using hapten I, based on esters of bis(pchlorophenyl)acetic acid (DDA), typically detected DDA with greater sensitivity than p,p′-DDT or p,p′-DDE. The most sensitive assay for p,p′-DDT (lower limit of detection of 0.3 µg/L) was obtained using an immunogen based on bis(p-chlorophenyl)ethanol (hapten IV), although a significant crossreaction with dichlorodiphenyltrichloroethane (DDD) and DDE was obtained. The most specific assay for p,p′-DDT was obtained using an immunogen (hapten VI) that includes all elements of the DDT structure, except that one of the p-chloro groups was replaced by β-alanine carboxamide for coupling to carrier proteins. Antibodies based on a similar DDE hapten (V) exhibited specificity for p,p′-DDE over p,p′-DDT. Greater specificity and sensitivity for dicofol were obtained by using an immunogen derived from ester hydrolysis of chlorbenzilate (hapten II). The assays provided methods for detection of p,p′-DDT plus p,p′-DDE either by using the antibody raised to hapten IV with conjugate based on hapten Ib or by using the assay based on hapten V, with treatment of samples with warm alcoholic KOH, which converted DDT to DDE. Some of the immunoassays were applied to the detection of DDT and DDE in water, soil, and selected foods.

Optical immunosensor for fast and sensitive detection of DDT and related compounds in river water samples

“…Limits of detection were approximately one order of magnitude lower than colorimetric ELISAs (Abad et al, 1997;Hochel and Musil, 2002) and slightly better than chemiluminescent ELISAs (Botchkareva et al, 2003). Among immunoassay methods used for DDT detection (Beasley et al, 1998;Valentini et al, 2003), only one work (Anfossi et al, 2004), based on a non-competitive immunoassay format, has reported slightly lower detection limits (8 ng L −1 ) than our SPR immunoassay format.…”

Gold nanoparticles based dipstick immunoassay for the rapid detection of dichlorodiphenyltrichloroethane: An organochlorine pesticide

“…Chickens were immunized with DDA-hapten to generate antibodies against DDT. The synthesis of DDA-hapten has been described by (Beasley et al, 1998). DDT and DDA found to show more than 95% cross reactivity.…”

Development of enzyme immunoassay for detection of DDT

“…In addition, the characterization of the polyclonal antibody indicated that the antiserum possesses a high specificity for p,p -isomers. Botchkareva et al [13] have developed the most sensitive ELISA with chemiluminescent detection for DDT compounds compared to the methods found in the literature; [11,12,15,16] for the DDT-selective assay, a limit of detection was estimated at 0.06 ng/mL. On the other hand, the detection limit of p,p -DDT in the EIA system developed in this study was about two times lower sensitivity than that in the DDT-selective assay reported by Botchkareva et al [13] However, in this study, the EIA system using antip,p -DDT antibody showed very high specificity for the parent compound p,p -DDT when compared with most previously published assays.…”