Magnetic poly(phenylene ethynylene) conjugated microporous polymer microspheres for bactericides enrichment and analysis by ultra-high performance liquid chromatography-tandem mass spectrometry

The novel multifunction materials for bactericides residue enrichment is attractive. Few materials used in bactericides analysis could simultaneously achieve convenient separation, recycling and trace enrichment. Therefore, a magnetic poly (phenylene ethynylene) conjugated microporous polymer (CMP) microspheres with three-dimensional network structure and covalently built-in Fe 3 O 4 nanoparticles was reported. The structure of dense poly (phenylene ethynylene) frameworks would enhance its conjugation system, which could adsorb bactericides with phenyl structure through π-π stacking. The material could be separated from sample matrix conveniently and recycled due to the super paramagnetism from embedded Fe 3 O 4 nanoparticles. After response surface optimization on extraction and desorption conditions, a method for trace analysis of six bactericides determination was developed by collaborative use of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The detection limits were in the range of 0.27–3.1 ng / L, and bactericides had been found in vegetables and fruits at concentration among 0.038-0.62 μg/kg. Finally, the method was further applied to analyze the regression equations of bactericide dissipation under natural condition. Effects of different treatment during cleaning process of vegetables and fruits were investigated to seek for the optimal cleaning method. The results revealed that the analytical method based on magnetic CMP which could achieve convenient separation, recycling and trace enrichment, having a great potential for trace analysis of more phenyl pesticides from real samples.