No abstract

The aim of this research is to develop an ultrasensitive time-resolved fluorescence immunoassay (TR-FIA) for herbicide diuron in water samples. This method appears to be a promising approach, instead of conventional analytical techniques, in the screening procedure of organic pollutants because it is simple, rapid, and specific, and it does not require sample preconcentration or cleanup. Lanthanide chelate used as label allows to achieve sensitivity even 10 times higher than most of the other techniques. It has been applied to monitoring diuron contamination in specimens collected along a year in an agricultural area. The water specimens were collected monthly from lake, well, and irrigation ditch in the agricultural area south of Milan. Assay was performed using diuron-specific polyclonal antibody raised in sheep; as fluorescent marker, we used rabbit antisheep IgG conjugated with a chelating molecule complexed with Eu3+. The compound 4-(3-(3,4-dichloro-phenyl)-1-methyl-ureido)-butyric acid (CPD) was synthesized and conjugated with bovine serum albumin (BSA) to prepare a solid phase. Sensitivity achieved was 20 ng L-1 below the European Community limits. Paraquat (PQ) and carbofuran (CF) presence in the same samples has been also evaluated in a similar way, using immunoassays with time-resolved revelation systems. Diuron concentration shows a peak coinciding with a peak of carbofuran during summer periods. The peak of diuron was 65 pg/mL in June and 180 pg/mL in September in ditch and lake water samples, respectively; carbofuran concentration was higher than diuron in all samples: a carbofuran peak was revealed in September and October resulting in 87 ng/mL. Herbicide paraquat was not detectable in any assayed sample.

No abstract

The water specimens were collected from wells and irrigation ditches in the agricultural area to the south of Milan and from Olona River and Mantua Lake and analyzed for paraquat detection. The assay was performed using a specific polyclonal antibody raised in sheep and rabbit anti-sheep IgG conjugated with a chelating molecule 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid complexed with Eu3+ as a fluorescent marker. Bovine serum albumin conjugated with 5-(1'-methyl[4,4']bipyridinyl-1-yl)pentanoic acid was used in solid phase preparation. The sensitivity achieved was 20 ng L(-1). The recovery in samples spiked with three different PQ concentrations was between 88 and 108%.