Rapid immunoanalytical method for the determination of atrazine residues in olive oil

Abstract

A sensitive, simple and reliable method has been developed for the determination of atrazine in extra virgin olive oil. The analytical procedure involves direct extraction of the target analyte from oil matrix with methanol and a freezing clean-up step (-80 degrees C) followed by plate or sensor immunoassay determination. A detection limit of 0.7 ng/mL, with a dynamic range from 1.0 to 10.4 ng/mL, was reached. The method was highly selective for atrazine and propazine, showing little or no cross-reactivity to other similar compounds. The excellent recoveries obtained (mean value 91.3%) confirm the potential of this approach to detect atrazine in olive oil for application as screening and complementary method in pesticide regulatory and food safety programs. The proposed method correlates well with the reference gas chromatography (GC-MS) technique.

Highly Sensitive Enzyme-Linked Immunosorbent Assay for Chlorpyrifos. Application to Olive Oil Analysis

“…Poor chlorpyrifos recoveries were achieved using standard curves in 2% methanol due to the matrix effect (Figure 2), as was also observed in previous studies (29). To normalize for matrix effects, the standard curves were made using spiked olive oil and extracted in the same way as the samples.…”

“…Therefore, methanol was the selected solvent for extraction purposes. Moreover, previous studies carried out by the authors on pesticide extraction in olive oil samples led to a simple and effective protocol using methanol (29). The features of the immunoassays at 2% methanol (final concentration in ELISA plate) were an I 50 of 244 ng L -1 , a working range between 74 and 2688 ng L -1 , and a LOD of 22 ng L -1 for assay A (Figure 2).…”

Improvement of a pesticide immunosensor performance using site-directed antibody immobilisation and carbon nanotubes

“…Enzyme-linked immunosorbent assay (ELISA) and immunosensing technologies have proved to be fast and sensitive screening methods, as well as quantitative analytical tools useful for pesticide residue determination in food and other matrices. So far, the major drawbacks for the application of pesticide immunoassay in food are related to bad recoveries and the removal of matrix interferences [8]. Immunosensor sensitivity is strongly dependant on the amount of immobilized antibodies and their remaining antigen binding properties.…”

Disseny d'immunosensors basats en format homogeni-heterogeni. Aplicació a la determinació de residus orgànics

“…investigacions sobre el comportament dels anticossos (Ab) en medis orgànics [202]. En els assaigs de transferència de fase, els anticossos romanen en el medi aquós mentre que l'antigen es troba en la fase orgànica i és en la interfase on transcorren les reaccions immunoquímiques .…”

“…Com mostra la Taula 28, en la determinació d'atrazina amb l'immunosensor H-H sols interfereixen la terbutilazina (23,5%) i la propazina (34,7%), igual que succeeix en els assaigs ELISA realitzats utilitzant els mateixos reactius [202]. Donat que amb l'immunoassaig no es pot assolir la sensibilitat requerida per a l'aigua potable es va plantejar la millora d'aquesta sense dur a terme l'etapa de preconcentració de la mostra, reduïnt el temps d'assaig.…”