Rapid Colorimetric Detection of Cartap Residues by AgNP Sensor with Magnetic Molecularly Imprinted Microspheres as Recognition Elements

• Published in: Molecules (Basel, Switzerland) Switzerland), 2018-06, Vol.23 (6), p.1443
• Main Authors: Wu, Mao, Deng, Huiyun, Fan, Yajun, Hu, Yunchu, Guo, Yaping, Xie, Lianwu
• Format: Article
• Language: English
• Subjects: Adsorption; Beverages; Cartap; cartap residue; colorimetric determination; Colorimetry; Ferrosoferric Oxide - chemistry; Health risks; Iron oxides; Metal Nanoparticles; Microspheres; Molecular imprinting; Molecular Imprinting - methods; Molecular Structure; molecularly imprinted microsphere; Nanoparticles; Pretreatment; Recognition; Residues; selective recognition; Silicon dioxide; Silicon Dioxide - chemistry; Silver; Silver - chemistry; silver nanoparticle sensor; Spectroscopy; Tea - chemistry; tea beverage; Thiocarbamates - adverse effects; Thiocarbamates - analysis
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23061443

The overuse of cartap in tea tree leads to hazardous residues threatening human health. A colorimetric determination was established to detect cartap residues in tea beverages by silver nanoparticles (AgNP) sensor with magnetic molecularly imprinted polymeric microspheres (Fe₃O₄@mSiO₂@MIPs) as recognition elements. Using Fe₃O₄ as supporting core, mesoporous SiO₂ as intermediate shell, methylacrylic acid as functional monomer, and cartap as template, Fe₃O₄@mSiO₂@MIPs were prepared to selectively and magnetically separate cartap from tea solution before colorimetric determination by AgNP sensors. The core-shell Fe₃O₄@mSiO₂@MIPs were also characterized by FT-IR, TEM, VSM, and experimental adsorption. The Fe₃O₄@mSiO₂@MIPs could be rapidly separated by an external magnet in 10 s with good reusability (maintained 95.2% through 10 cycles). The adsorption process of cartap on Fe₃O₄@mSiO₂@MIPs conformed to Langmuir adsorption isotherm with maximum adsorption capacity at 0.257 mmol/g and short equilibrium time of 30 min at 298 K. The AgNP colorimetric method semi-quantified cartap ≥5 mg/L by naked eye and quantified cartap 0.1⁻5 mg/L with LOD 0.01 mg/L by UV-vis spectroscopy. The AgNP colorimetric detection after pretreatment with Fe₃O₄@mSiO₂@MIPs could be successfully utilized to recognize and detect cartap residues in tea beverages.