| In recent years, the problem of melamine illegally added into the foods and feeds is repeated, which has threatened to human and pets health and safety.Thus, a rapid, sensitive and stable surface plasmon resonance (SPR) immunosensor based on the inhibition format was developed and validated for detecting melamine (MEL) in milk products and pet foods in this project.In this experiment, MEL was detected through the change of sample response, which caused by the antigen-antibody binding reaction on the chip surface. In the optimized condition, the acetate buffer pH 4.5 was used to be coupling buffer for coating the chip. And 0.1 mol L-1 of HCl was selected to be the regeneration with a positive result, which made sensor chips could be reused up to 500 times in a month with response value varying less than 5%. Different concentrations of MEL were detected using 5 ?g mL-1 antibody concentration with a good liner range (1.4 × 10-3-0.17 ?g mL-1) in the method. And the sensitivity (IC50) and the limit (IC15) of detection of the proposed method for MEL were 2.32 × 10-2?g mL-1 and 1.4 × 10-3?g mL-1 respectively. The immunosensor was highly specific to MEL, which only displayed low cross-reactivity (CR) (< 0.01%) for cyanuric acid, cyanuric chloride and atrazine except cyromazine. The assay was validated for the detection of MEL in full cream milk, skim milk powder, infant formula, dog food and cat food with a good recovery results of 76.4%-105.0%; 97.9%-99.9%; 79.0-113.5%; 86.0%-113.3%; 73.5%-109.4% espectively. The sensitivity of the assay in each type of sample was 2.57 × 10-2?g mL-1,2.32 ×10-2?g g-1,2.51 × 10-2?g g-1,2.66 × 10-2?g g-1 and 2.68 × 10-2?g g-1, respectively, which were much lower than the maximum residue levels (MRLs) of MEL.By this method, it only takes within 15minutes to detect the residue MEL in food samples. Under the optimal experimental conditions, SPR immunosensor shows sensitive, rapid and stable to detect the MEL in food samples. |
PDF Full Text Request