Determination of paraquat residues in soil by an enzyme linked immunosorbent assay

Abstract

A rapid, convenient and accurate method, based upon an enzyme linked immunosorbent assay (ELISA), is described for the determination of paraquat residues in soil. Polystyrene plates, coated with paraquatkeyhole limpet haemocyanin (KLH) conjugate, are incubated with the test samples and a known amount of monoclonal antibody. Residual antibody that has not reacted with free paraquat in the sample combines with paraquat -KLH on the plate. The determination of the fixed antibody is achieved by the addition of peroxidase labelled rabbit anti-mouse immunoglobulin G followed by reaction with a chromogenic substrate. The enzyme activity of the solid phase is determined from the absorbance measurements, which are inversely proportional to the concentration of paraquat. The method shows high specificity and correlates well with the traditional ion exchangespectrophotometric method for the determination of paraquat.

Development of an ELISA for paraquat; improvement of antibody characteristics by reversed affinity chromatography

“…6 Further work on the assay will lead to optimisation for a variety of matrices, particularly soil samples. 26 It may also be adapted for susceptible foodstuffs 13 and used by clinicians in determining cases of paraquat poisoning. 19 Some common problems encountered in the development of polyclonal antibody-based immunoassays for haptens were observed; typically, the time taken for observation of displacing antibodies, and less than optimal standard curves.…”

Selective Kinetic Determination of Paraquat Using Long-Wavelength Fluorescence Detection

“…The results obtained show that the proposed method is a suitable alternative for the simple and fast determination of paraquat. Unlike the enzyme immunoassay methods described for paraquat (Niewola et al, 1985(Niewola et al, , 1986Van-Emon et al, 1986;Selisker et al, 1995), which require several incubation steps, the analytical results with this method are obtained in only a few seconds by using a stopped-flow mixing technique, which allows determination of reproducible values of the fast reaction rate of this system and provides a means of accomplishing automation in routine analysis.…”

“…Diquat (1,1′-ethylene-2,2′-dipyridinium ion), which is structurally related to paraquat and also forms a stable colored radical, is one of the most serious interferences in the photometric methods for paraquat. Treatment with sodium hydroxide has been recommended for the removal of diquat (Yan ˜ez-Seden ˜o and Polo-Diez, 1986), but the maximum tolerable diquat/paraquat ratio is 1.9 and the treatment takes 5-6 h. Several enzyme immunoassay methods have been reported for paraquat determination (Niewola et al, 1985(Niewola et al, , 1986Van-Emon et al, 1986;Selisker et al, 1995), in which the interference of diquat is avoided by using very selective monoclonal antibodies.…”

Electrochemical studies and square wave voltammetry of paraquat at natural phosphate modified carbon paste electrode

“…In the literature there are numerous methods reported for the determination of paraquat. Until now the analytic approach varies [5,6], including a biological dosage [7,8], spectrophotometry [9][10][11][12], chromatography CLHP (UV) or (CPG) [13][14][15][16], immunoassay [17,18], potentiometry [19,20] and polarography [21]. The electrochemical determinations of paraquat have been also performed at different electrode surfaces [22][23][24][25][26].…”