Determination of Congo red in food samples by methyl-β-cyclodextrin/Triton X-100 synergistic sensitized fluorescence quenching method of the derivatives of calix[4]arene

A novel fluorescent chemosensor of the derivatives of calix[4]arene (SAX) for Congo red (CR) in methyl-β-cyclodextrin/Triton X-100 synergistic sensitized system was developed. The results showed that the fluorescence intensity of SAX could be quenched by CR, and the fluorescence quenching (∆F = FSAX − FCR-SAX) was synergistic sensitized by methyl-β-CD and Triton X-100. Under the conditions of λex/em = 332/468 nm and pH 7.5, the linear range and the detection limit for CR were found to be 0.040–8.0 μg/mL and 8.9 ng/mL, respectively. The mechanism of determination was discussed by quenching type analysis and sensitizing effect. This method has also been applied for the determination of CR in beef samples with satisfactory results.