A simple, highly sensitive, high throughput and organic solvent-free screening method for melamine by microsphere-based flow cytometry immunoassay

Abstract

In recent years, the safety problem of infant formula powder has provoked panic among Chinese citizens. One of the most notorious incidents was the 2008 Chinese milk scandal which harmed thousands of infants. Therefore the development of a fast, high throughput screening method towards melamine and other harmful chemicals is of paramount importance. Microsphere-based flow cytometry is a new multiplexing immunochemical method for food-testing. Through competition between the free analyte in the sample and analyte-coupled microspheres, the content of the analyte can be indirectly quantified by measuring the fluorescence emitted from labelled antibodies. This developed method of high sensitivity (limit of detection = 0.70 ng ml⁻¹) has already been validated and successfully applied to screen for melamine in various brands of infant formula powder analysis fulfilling the legislated tolerance level in a simple, fast, high throughput and organic solvent-free manner.