Sensitive and renewable picloram immunosensor based on paramagnetic immobilisation |
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Authors: | Guang-Ming Zeng Lin Tang Li-Juan Chen Ya Pang Chong-Ling Feng |
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Institution: | 1. College of Environmental Science and Engineering , Hunan University , Changsha 410082 , China;2. Key Laboratory of Environmental Biology and Pollution Control (Hunan University) , Ministry of Education , Changsha 410082 , China zgming@hnu.cn;4. Key Laboratory of Environmental Biology and Pollution Control (Hunan University) , Ministry of Education , Changsha 410082 , China |
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Abstract: | Picloram (4-amino-3,5,6-trichloro-2-pyridincarboxylic acid) is one of the chlorinated pesticides. It is widely used for control of wood plants, wheat, barley and wide range of broadleaf weeds as a plant growth regulator. An immunosensor was developed for detection of picloram concentration in compost extracts and river water. The laccase-picloram was prepared. The magnetic core-shell (Fe3O4-SiO2) nanoparticles were modified with anti-picloram-IgG and attached to the surface of carbon paste electrode (CPE) with the aid of paramagnetism. Following competitive immunoreaction with picloram and the picloram-laccase to form immunocomplex, electrochemical measurement was carried out. After immunoassay, the electrode was immersed in glycin-hydrochloric acid buffer or polished with diamond paper for regeneration. The linear range for picloram detection was 1?×?10–4–10?µg?mL–1 with the correlation coefficient of 0.9936, and the detection limit is 1?×?10–4?µg?mL–1. The laccase labelled on the picloram for competitive immunoassay showed good activity, and the current response was strong and stable in electrochemical detection. The current reached 95% of the steady-state current within about 100?s. The proposed immunosensor exhibited good precision, sensitivity, selectivity, reusability, and storage stability. |
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Keywords: | immunosensor picloram magnetic nanoparticles laccase regeneration |
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