| Object Arsenic is widely distributed in nature,natural waters of arsenic pollution is a world problem,people through drinking high arsenic water can lead to skin cancer,liver cancer and so on.Arsenic is present in the form of compounds in drinking water,mainly trivalent arsenic As(?),monomethyl arsenic acid(MMA),dimethyl arsenic acid(DMA)and pentavalent arsenic As(V).The toxic effects of arsenic not only depends on the total arsenic,but also depends on the form of its existence.Different chemical forms of arsenic compounds have different metabolic and toxic mechanisms,and the toxicity is also very different.At present,China's determination of arsenic in drinking water is mainly to determine the total arsenic concentration,research drinking water arsenic morphology analysis method less.And the determination of total arsenic in the form of hygienic evaluation,can not accurately reflect the arsenic exposure level and arsenic on the environment,ecology and the human body,so the various forms of arsenic analysis and determination of important,The aim of this study was to establish a high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry technique for the determination of arsenic: As(?),MMA,DMA and As(V)in the drinking water quality,Method to detect arsenic in different areas of water quality,for the future development of China's arsenic national standard detection methods and limits to provide technical basis.Method Four kinds of arsenic were separated by anion exchange column of liquid chromatography using high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry(HPLC-HG-AFS),and then in the arsine generator in turn by the potassium borohydride in acidic solution redox reaction reduced to gaseous arsine,argon as carrier gas,the arsine from the mother liquor separation,into the quartz atomizer Atomic analysis.The effects of negative pressure and lamp current,carrier gas flow rate,reducing agent concentration,current carrying velocity,mobile phase concentration and PH experimental conditions were optimized by single factor rotation method and orthogonal design method.Good condition.Using the retention time qualitative,peak area external standard method quantitative.At the same time,the detection limit,linear range,precision,accuracy and sample stability of the method are studied and discussed.The method was applied to the detection of actual drinking water.A total of 40 samples were collected from tap water or well watercollected by college students from different regions.And the actual water samples of the test results of the uncertainty assessment to ensure the reliability and accuracy of sample testing,evaluation of certainty by the standard material purity,the standard solution reserve solution configuration and standard curve fitting,etc.Results Buffer solution of diammonium phosphate with pH 6.0,the concentration of 2.0g / L,carrier solution for 7% hydrochloric acid,reducing agent 0.50% sodium hydroxide and 2.0% potassium borohydride mixed solution,do not open the UV online digestion device,negative High pressure 330 V,arsenic lamp current 50 mA,carrier gas flow selection of 250 ml / min.Under the above conditions,the four kinds of arsenic separation were complete,the peak of the chromatogram was high,no tailing,no interference peak,peak time was fast and the response value was the highest.The method has the advantages of good linearity: trivalent arsenic y1 = 339.87x1 + 270.16,R1=0.9995,detection range0.36 ? 111.87?g / L;monomethyl arsenic y2 y2 = 175.99x2 + 38.534,R 2=0.9999,detection range 0.69? 83.16?g / L;dimethyl arsenic y3 = 158.87x3 + 78.891,R 3=0.9997,detection range 0.39 ? 87.66?g /L;pentavalent arsenic y 4= 94.483x4 + 99.209,R4 =0.9991,detection range 2.34 ? 116.64?g / L.The detection limits of trivalent arsenic,monomethyl arsenic,dimethyl arsenic and pentavalent arsenic were0.36?g / L,0.69?g / L,0.39?g / L and 2.34?g / L.The average recoveries ranged from 95.7% to 107.9%,and the relative standard deviations were 0.23% ? 9.31%.The samples were stored in a refrigerator at 4? for at least 14 days.The loss rates of As(?),As(?),MMA and DMA were 3.43%,3.30%,1.44%and 3.82%,respectively.Application of established methods in drinking water samples,a total of58.32?g / L pentavalent arsenic was detected in a well from Qinghai,the rest were not detected,and the recoveries were 94.4% ? 107.8%.The uncertainty result of the method shows that the standard curve fitting is the most important factor affecting the uncertainty of the experiment.The standard material purity and the standard solution reserve solution will bring some errors to the experiment.The total standard uncertainty of the pentavalent arsenic was 2.16?g / L.The use of this method to determine the arsenic content of drinking water should be reported as:(58.32 ± 4.31)?g / L.Conclusion: A method for the determination of arsenic in drinking water by high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry was established.The pH and concentration of buffer solution were determined by single factor rotation method and orthogonal design method,the concentration of the carrier solution and the concentration of the reducing agent,the use of UV on-line digestion devices,the study of negative high pressure,lamp current and carrier gas flow conditions.The HPLC-HG-AFS method was optimized and analyzed,and four kinds of arsenicwere well separated and high fluorescence response values in this study.The method of drinking water samples is simple to pretreat,no need to digest,can be measured directly by the filter,high sensitivity,good precision,uncertainty to meet the requirements,the results are accurate and reliable.The method of morphological analysis of arsenic in drinking water was established,which provided technical support for the effective risk assessment of drinking water quality.The method could be used for the monitoring and analysis of arsenic pollution in drinking water. |
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