Development of an Enzyme-Linked Immunosorbent Assay for the Detection of Glyphosate

Abstract

A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide glyphosate [N-(phosphonomethyl)glycine] in water. The ELISA has a detection limit of 7.6 microg mL(-1) and a linear working range of 10-1000 microg mL(-1) with an IC(50) value of 154 microg mL(-1). The glyphosate polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with the glyphosate metabolite aminomethylphosphonic acid and a structurally related herbicide, glyphosine [(N,N-bis(phosphonomethyl)glycine]. The assay was used to estimate, quantitatively with accuracy and precision, glyphosate concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, water samples were concentrated prior to analysis, resulting in the increase of the detection limits by 100-fold. After the sample preconcentration step, the detection limit improved to 0.076 microg mL(-1) with an IC(50) value of 1.54 microg mL(-1), and a linear working range was 0.1-10 microg mL(-1). Glyphosate concentrations determined by ELISA correlated well with those determined by high-pressure liquid chromatography (r(2) = 0.99). This assay contributes to reducing the costs associated with conventional residue analysis techniques for the quantitation of glyphosate in water.

Applying weight gain in Pomacea lineata (Spix 1824) (Mollusca: Prosobranchia) as a measure of herbicide toxicity

“…do not directly measure toxicity. In this regard, ELISA assays have been developed for some of the herbicides (Clegg et al, 1999(Clegg et al, , 2001. While these assays have proved accurate, rapid and more cost-effective than conventional chromatographic analysis, the methods' sophistication and cost preclude their routine application throughout the region.…”

Immunomodulation confers herbicide resistance in plants

“…As exemplified by the diverse array of antibodies available for binding herbicides with unique chemical structures and modes of action, antibodies can be raised against or selected for specific binding to a seemingly unlimited repertoire of haptens (< 1000 Da) (Meulenberg et al ., 1995; Parnell and Hall, 1998; Clegg et al ., 1999, 2001; Webb and Hall, 2000). In this study, we tested the hypothesis that antibodies with specific xenobiotic affinities are able to generate xenobiotic resistance when expressed in plants.…”

Forty Years with Glyphosate

“…Among various immunoanalytical techniques, enzyme-linked immunosorbent assays (ELISAs) gained the highest utility. While in the early nineties we considered yet that effective antibodies are not produced against glyphosate and similar zwitterioninc compounds due to their low immunogeneity (Hammock et al, 1990), difficulties in immunisation have been overcome within a decade, and sensitive ELISAs, also employing derivatisation, were developed (Clegg et al, 1999;Lee et al, 2002b;Rubio et al, 2003;Selvi et al, 2011), proven to be of great utility in environmental analytical studies for glyphosate (Mörtl et al, 2010;Kantiani et al, 2011). On the basis of the immunoassay principle, sensors using glyphosate-sensitive antibodies (González-Martínez et al, 2005) or molecularly imprinted polymers (MIPs) (Zhao et al, 2011) were also developed.…”