Development of an optical fiber immunosensor for the rapid and sensitive detection of phthalate esters

A rapid and sensitive detection method for phthalate esters (PAEs) was developed by using an optical fiber immunosensor based on indirect competitive immunoassay. This sensor was constructed by covalent binding of coating antigen on the surface of optical fiber, and the inhibition signal of PAEs to immune reaction between coating antigen and fluorescent-labeled antibody was detected by avalanche photodiode. The response signal showed a negative correlation with the logarithm of PAEs concentration in the range of 0.01-100 mu g/L, and the limits of detection (LODs) of eight PAEs ranged from 19 to 51 ng/L. The fluorescent-labeled antibody displayed broad cross-reactivity in the range of 16.63%-71.94% for the others even PAEs (100% for dimethyl phthalate). The average recoveries of PAEs at the spiked levels of 5, 10 and 100 mu g/kg ranged from 61.5% to 106.7% with relative standard deviation (RSD) values below 13.41%, and these results were consistent with those obtained by gas chromatography-mass spectrometry (GC-MS). The optical fiber immunosensor has good regeneration performance, reproducibility and stability, and displays wide linear range, high sensitivity, simple sample pretreatment and short detection time for PAEs detection. The new method has been successfully applied to the determination of multiple PAEs in greenhouse soils. (C) 2017 Elsevier B.V. All rights reserved.