Rapid And Ultrasensitive Detection Of Hg²⁺ In Drinking Water Based On Novel UV -vis Spectrophotometry And Fluorescence Spectrophotometry

Hg²⁺is one of the major pollutants in the world and is particularly serious in the water environment,which is closely related to the quality and safety of drinking water and poses a great threat to health and safety of public.At present,the classical detection methods in laboratory are high-costing,time-consuming and complicated,the filed detection methods are one-to-one and low-sensitive,which can not satisfy the urgent demands for rapid,simple and high-costing determination of ultratrace Hg²⁺in environmental drinking water.Thus,two methods for the detection of Hg²⁺have been established based on UV-vis spectrophotometry and fluorescence spectrophotometry.The principle of first method is the color reaction of Hg²⁺,I^-and alkali blue in acidic buffer of H₃PO₄-NaH₂PO₄.The optimal reaction scheme was determined by analyzing the UV spectrums,the zeroing scheme,the amount of KI and color reagent,the pH of color reagent and reaction time were optimized.Under the optimum reaction condition,the standard curve for the detection of Hg²⁺in environmental drinking water was established,the dynamic quantitative working ranges was 0.001-0.1 mg/L and the lowest detection limit was 0.0024 mg/L.It indicated that the detection system has wide detection interval and high sensitivity.This method was highly specific for detecting of Hg²⁺without being affected by other possible interfering ions from different background compositions of water samples.The recoveries of Hg²⁺spiked in different water samples were 95.05-103.51%with relative standard deviation below 10%,the result was satisfied.The reliability of the detection method is verified by comparison with AFS.The higher sensitivity and specificity detection method is established by combining with the traditional enrichment method or the enrichment of nanomaterials.It is possible to develop a handheld equipment for the detection of Hg²⁺in environmental drinking water with the gradual miniaturization of UV-vis spectrophotometer.It has great potential for detection of individual and household detection,emergency disposals for outburst of environmental pollution incidents and health care of military.In addition,a novel label-free fluorescence assay for detection of Hg²⁺was developed based on the Hg²⁺-binding ssDNA and SG I.The scanning conditions,buffer solution,the dilution multiple of SG I and reaction time are optimized,then the standard curve for the detection of Hg²⁺in environmental drinking water was built by segmentation fitting.The dynamic quantitative working ranges was 5-1000 nM and the lowest detection limit was 3 nM which was satisfy the sanitary standard for drinking water（GB5749-2006）and well below the standard of U.S.Environmental Protection Agency.The specific verification experiment was carried out to prove the high specificity of the detection system.The actual detectability was investigated by standard recovery test and method comparison.The spiked recoveries were 95.05-103.51%and the relative standard deviation was below 10%.The method exhibited the characteristics of low cost by calculating the price of reagent for single measure.The proposed method is more viable,low-costing and simple for operation in detection than the other DNA based methods for determination of Hg²⁺,making it easy to be integrated and automatized in microfluidic chip and sensors in the future.Great potentials are applicable by the proposed assay in detection of heavy metals for emergency disposal,environmental monitoring,surveillance and supporting of ecological risk assessment and management.