Study On Rapid Detection Of Escherichia Coli By Surface Enhanced Infrared Absorption Spectra

In recent years,environmental problems have become increasingly serious.Water pollution incidents have become frequent,which have leaded ecological damage and even affected human health.The birth of various pathogenic bacteria was an important reason.So it is important to establish a rapid detection of certain pathogenic bacteria,Escherichia coli（E.coli）,for early prevention of certain health problems.Infrared spectroscopy technology could be used for qualitative analysis,and the surface enhanced infrared absorption spectroscopy（SEIRAS）is highly sensitive.Therefore,in this paper,based on Fourier transform infrared spectrometer（FT-IR）,transmission surface-enhanced infrared absorption（T-SEIRAS）substrate was simple operation,high sensitivity,and could meet the requirements of rapid detection.The T-SEIRAS substrate might be used in the detection of E.coli,with high research value.First of all,in this paper,sulfhydryl compounds were selected as probe molecules,which were used to characterize the enhanced substrate.The article chose the porous material copper foamy（CF）,as a substrate,with a gr eater hardness and more stable physical and chemical properties compared with the nickel foamy.At the same time,as a result of academic circles is generally believed that noble metal nanoparticles to measurement of infrared signal had an enhanced markedly affection,according to the different wet chemical methods to select out the gold/silver nanoparticles（Au/Ag NPs）and nano particles of silver iodide（AgI NPs）.In the reaction process,sodium citrate,sodium borohydride and hydroxylamine hydrochloride（NH₂OH·HCl）were screened out.The reaction time and reaction reagent ratio also needed being optimized.Finally the paper got four T-SEIRAS substrates.The first is the the CF-PEI（polyethylene amide）-Au NPs-PVP（polyvinylpyrrolidone）.The second is the CF-Au NPs.The third is the CF-Ag NPs.The forth is the CF-AgI NPs.Then,the above four T-SEIRAS substrates had extremely sensitive infrared enhancing signal response,for example 11-Mercaptoundecanoic acid（MUA）,4-Mercaptobenzoic acid（MBA）and 4-Aminothiophenol（ATP）,etc.At the same time,the two enhanced substrates of the second and the third for E.coli had an obviously enhanced infrared signal.At the same time,the most important achievement was the detection of E.coli.The CF-Au NPs and the CF-Au NPs that could both make enhanced factors of E.coli become at least 2 times.About 30 minutes before and after the detection of E.coli was needed,which was also greatly shortens time of the sample test.To sum up,based on the prepared T-SEIRAS substrate,it was established infrared analysis method,which could realize rapid detection of E.coli.SEIRAS method should be promoted in the field of environmental monitoring.The technique had important practical significance.