Determination of Carbaryl in Vegetables Using an Immunosensor Working in Organic Media

Sensitive and rapid analysis of carbaryl using a flow immunosensor is described. An azlactone polymeric gel with covalently bound Protein A/G was used as immunofiltration support. The immunosensor was able to work at high concentrations of organic solvents (e.g. up to 50% MeOH) using a competitive enzyme-immunoassay protocol, with an analysis rate of a complete assay cycle in 22 min. Good sensitivity (I₅₀ = 9.05 mugl^-1) was achieved in organic media and the reusability of the sensor was at least 300 cycles without loss of performance. The sensor was applied to the analysis of carbaryl extracted by both multiresidue method and methanol in fresh and processed vegetable samples. The analytical results were compared with those obtained by ELISA and high-performance liquid chromatography (HPLC) methods. A good agreement was achieved by both immunological methods (r = 0.98) and those obtained by HPLC technique. The results indicated the suitability of the immunosensor for carbaryl analysis in vegetable samples due to its reproducibility, rapidity and compatibility with organic solvents.