A hollow visible-light-responsive surface molecularly imprinted polymer for the detection of chlorpyrifos in vegetables and fruits

• Published in: Food chemistry 2021-09, Vol.355, p.129656, Article 129656
• Main Authors: Chen, Mei-jun, Yang, Hai-lin, Si, Ya-min, Tang, Qian, Chow, Cheuk-fai, Gong, Cheng-bin
• Format: Article
• Language: English
• Subjects: Chlorpyrifos; Chlorpyrifos - analysis; Food Analysis - methods; Food Contamination - analysis; Food safety; Fruit - chemistry; Light; Molecularly imprinted polymer; Molecularly Imprinted Polymers - chemical synthesis; Molecularly Imprinted Polymers - chemistry; Pesticide residue; Surface imprinting technique; Vegetables - chemistry; Visible-light-responsive material; Water - chemistry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.129656

•A surface molecularly imprinted polymer (PS-co-PMAA@VSMIP) was prepared.•A hollow structured surface molecularly imprinted polymer (HVSMIP) was prepared.•Both PS-co-PMAA@VSMIP and HVSMIP were visible-light-responsive.•HVSMIP performed better than PS-co-PMAA@VSMIP for chlorpyrifos analyte.•HVSMIP was applied to detect trace chlorpyrifos in spiked apple and carrot samples. A visible-light-responsive azobenzene derivative, 3,5-dichloro-4-((2,6-dichloro-4-(methacryloyloxy)phenyl)diazenyl)benzoic acid, was synthesized and used as the functional monomer to fabricate a visible-light-responsive core-shell structured surface molecularly imprinted polymer (PS-co-PMAA@VSMIP). After removal of the sacrificial PS-co-PMAA core, a hollow structured surface molecularly imprinted polymer (HVSMIP) was obtained. Both the PS-co-PMAA@VSMIP and HVSMIP were used for the detection of chlorpyrifos, a moderately toxic organophosphate pesticide. They exhibited good visible-light-responsive properties (550 nm for trans→cis and 440 nm for cis→trans isomerization for an azobenzene chromophore) in ethanol/water (9:1, v/v). Compared with the PS-co-PMAA@VSMIP, the HVSMIP had a larger surface area, pore volume, binding capacity, imprinting effect, maximum chemical binding capacity, dissociation constant, and photo-isomerization rate. The HVSMIP was applied to detect trace chlorpyrifos in fruit and vegetable samples. This was achieved by measuring the trans→cis rate constant of the HVSMIP in the sample solution, with good recoveries, low relative standard deviations, and a low detection limit.