Application Of Molecularly Imprinted Colorimetric Paper Chip With Smart Phone In Water Environment Analysis

In recent years,environmental problems have become more and more important,and people’s understanding of the importance of environmental protection has become more and more profound.The idea that green water and green mountains are golden mountains and silver mountains has become more popular.Nowadays,the first step to solve environmental problems is the analysis and testing of environmental pollutants.With the development and progress of the times,higher requirements are put forward for environmental analysis and testing.At the same time,more efficient,portable and low-cost analysis and testing equipment,the high-efficiency,portability and low-cost characteristics of microfluidic paper chips just meet the needs of portable environmental analysis and testing equipment.By building more detection methods on the paper-based platform and improving the analysis and detection capabilities of the paper chip,it can be better applied to environmental analysis and detection.Based on paper chips,we have designed and manufactured two colorimetric paper chips that can be used for rapid and convenient detection of environmental pollutants,we use molecular imprinting technology and nano-zinc ferrite catalyze the color development principle of H₂O₂ and3,3’,5,5’-tetramethylbenzidine reaction,combined with smart phone photography The functionally constructed paper-based colorimetric sensing platform realizes the rapid analysis of oxytetracycline and microcystin.The contents are summarized as follows:1.A colorimetric microfluidic paper chip based on molecularly imprinted zinc ferrite nanoparticles was used to detect oxytetracycline in water environment.A novel colorimetric microfluidic paper chip was developed to perform specific recognition,adsorption and sensitive detection of oxytetracycline.Molecularly imprinted polymers were prepared with zinc ferrite nanoparticles as the core,oxytetracycline as a template,and acrylamide as a functional monomer.The zinc ferrite nanoparticles were used as peroxidase mimics to catalyze the conversion of 3,3’,5,5’-tetramethylbenzidine into blue,showing different intensity of color.The color status of the paper-based colorimetric chip was captured by the mobile phone,and the captured image was analyzed by software to obtain accurate quantitative information of oxytetracycline.This paper studies the preparation and micro-morphology of the paper chip,optimizes the reaction conditions such as buffer p H,hydrogen peroxide concentration and 3,3’,5,5’-tetramethylbenzidine concentration,and studies the detection ability and selectivity of the paper chip.The results showed that under optimized conditions,the detection range was 10～400μg/L,and the detection limit was 2.34μg/L.It was successfully applied to the determination of oxytetracycline in tap water and seawater samples.The standard addition analysis showed that the recovery rates of standard addition were 98.8%～102.2%and99.5%～104.5%respectively.2.A colorimetric microfluidic paper chip based on segment molecularly imprinted technique was used to detect microcystins in water environment.A novel type of colorimetric sensor based on microfluidic paper chip was developed for the determination of microcystin-RR in complex water samples by using segment molecularly imprinted technique and Fenton reaction.L-arginine was used as segment imprinting template,methacrylic acid,ethylene glycol dimethacrylate and 2,2’-azobis（2-methylpropionitrile）were used as functional monomers,crosslinkers and initiators respectively.The surface of zinc ferrite nanoparticles was coated with molecularly imprinted polymers to control the color reaction between hydrogen peroxide and 3,3’,5,5’-tetramethylbenzidine.A smart phone was used to track the color intensity change of the paper chip to detect MC-RR at different concentrations.Scanning electron microscope and Fourier transform infrared spectrometer were used to characterize the production materials and colorimetric sensor microfluidic paper chip.Then the reaction conditions of the paper chip were optimized and the analysis performance of the paper chip was discussed.The detection level of the colorimetric paper chip for MC-RR is as low as 0.44μg/L,and it has been successfully applied to the detection of MC-RR in lake water and seawater samples.The recovery rates of standard addition were 94.9%～105.0%and 96.6%～104.2%,respectively.