Development of an immunoassay for terbutryn: study of the influence of the immunization protocol.

Heterologous immunization has proven to be useful to enhance the selectivity and specificity of catalytic antibodies. However, in the field of immunoassays, few studies have been done to establish how the immunization protocol influences the antibody characteristics. In the present study, we have developed an enzyme-linked immunosorbent assay (ELISA) for the detection of the pesticide terbutryn following a homologous and a heterologous immunization strategy. No significant differences have been observed between the immunization procedures regarding immunoassay sensitivity and selectivity. Thus, immunoassays with a limit of detection below the 25 ng/l established by current European regulations have been obtained with both immunization protocols. Initial studies have been performed to assess the applicability of these ELISAs to the analysis of real water matrixes.

Studies on toxic oil syndrome: development of an enzyme-linked immunosorbent assay for 3-(N-phenylamino)propane-1,2-diol in human urine.

The fatty acid esters of 3-(N-phenylamino)propane-1,2-diol (PAP) are biomarkers of toxic oil batches that caused toxic oil syndrome (TOS), an intoxication that caused over 400 deaths and affected 20,000 people in Spain in 1981. PAP esters are converted into PAP by human pancreatic lipase. The in vivo biotransformation of PAP in two mouse strains generated potentially toxic metabolites. Here we report an enzyme-linked immunosorbent assay (ELISA) for PAP detection incorporating antibodies generated using PAP-hapten derivatives 1 and 2. The immunizing haptens were designed to recognize the phenylamino and hydroxymethylene moieties of the PAP structure. The antisera raised against 1-HCH showed greater affinity for free PAP, as demonstrated in competitive experiments using either 1-BSA or 2-BSA as coating antigens. The developed ELISA detects PAP at a threshold of 130 µg L(-1) and can be used over a wide range of pH and ionic strength values. The assay can be applied to human urine samples, after a simple treatment method, with good recovery according to the correlation obtained when analyzing blind spiked urine samples.

Immunochemical determination of 2,4,6-trichloroanisole as the responsible agent for the musty odor in foods. 2. Immunoassay evaluation.

Immunoassays for 2,4,6-trichloroanisol (TCA) have been evaluated. The assays were developed after raising antibodies against three different immunizing haptens (1). Lack of reproducibility has been one of the main problems of these assays. Precision was worse on these assays, reaching lower limits of detection. The high lipophilicity of TCA and its, consequently, low water solubility have been found to be the major cause of this problem. A reliable microplate-based enzyme-linked immunosorbent assay (ELISA) has been set after consideration of the TCA physicochemical features and evaluation of important parameters affecting immunoassay performance. The immunoassay uses As78 (developed against hapten B-KLH) and C9-OVA as the coating antigen. The selectivity is high although the brominated analogue 2,4,6-TBA is also recognized. In buffered media containing 7% ethanol, the resulting assay shows a good accuracy with an IC(50) value of 0.53 microgram L(-)(1) and a limit of detection of 0.044 microgram L(-)(1). Red and white wine samples caused important interferences in the immunoassay demonstrating the necessity of a cleanup procedure prior to the ELISA.

Tris(2,4,6-trichloro-3,5-dinitrophenyl)methyl radical: a new stable coloured magnetic species as a chemosensor for natural polyphenols.

We report the synthesis, electron paramagnetic resonance and electrochemical properties of a novel stable radical of the TTM series. Its strong electron acceptor ability has been tested with (-)-epicatechin, a natural polyphenolic antioxidant.

Valorization of grape (Vitis vinifera) byproducts. Antioxidant and biological properties of polyphenolic fractions differing in procyanidin composition and flavonol content.

Many byproducts and wastes generated by agroindustries contain polyphenols with potential application as food antioxidants and preventive agents against skin cancer and other diseases. The performance of polyphenolic fractions from Parellada grape (Vitis vinifera) pomace as antioxidants in different physicochemical environments was tested. Fractions containing oligomers with mean degree of polymerization between 3 and 4 and percentage galloylation ca. 30% were the most potent free radical scavengers and efficient antioxidants in an oil-in-water emulsion. A fraction including glycosylated flavonols was also efficient in the emulsion. All the fractions showed low aquatic toxicity and weak influence on proliferation of human melanoma cells.