| With the development of social economy,people have put forward higher requirements for the quality of drinking water which results in that the water quality testing becomes more particularly important.More and more new technologies have been applied to water quality detection so that the green chemistry and automation detection are the development trends of detection work.It can decrease the amount of toxic and harmful reagents reduce the harm of experiments to analysts,and protect the health of workers.This paper optimizes the detection methods for aluminum,hexavalent chromium,and iodide in drinking water.The method for determining aluminum in drinking water using chrome azurol S spectrophotometry was optimized.The main factors affecting the determination of aluminum ions were investigated,including the properties of buffer solution,pH value,and chromogenic agent concentration.The experimental results indicate thatthe most important factor affecting the determination is the properties of the buffer solution,and ammonium acetate buffer solution has the best effect in detecting aluminum ions under fixed instruments and constant temperature and humidity.The optimum plan was determined by studying the addition amount,reaction time,linear range,and maximum absorbance of various reagents.The optimized method was compared with the national standard method and the results showed no significant difference.The linear range of the method was 0.008～0.200 mg/L with the correlation coefficient r greater than 0.999.The detection limit was 0.002 mg/L.The relative standard deviation was 0.83%～2.43%,and the relative error of certified reference materials was 1.7%～2.0%.The method of diphenylcarbazide spectrophotometry for determining hexavalent chromium in drinking water was improved.The effects of different acid systems and diphenylcarbazide-solvents on the determination of hexavalent chromium were studied.The results showed that nitric acid and ethanol diphenylcarbazide was the best plan,and their dosage was also optimized.The optimized method did not differ from the results of the national standard method,but with the safer reagents.The detection limit of the method was 0.002 mg/L with the correlation coefficient r greater than 0.9995.the relative standard deviation was 1.35%～3.83%,and the spiked recovery rate was 94.0%～104%.The certified reference material was in accordance with the requirements of the certificate.The method for iodide determination in drinking water by ion chromatography was investigated.A SH-AP-1 chromatographic column with a eluent concentration of 25 mM KOH was performed with a flow rate of 0.7 mL/min.The column temperature of 35℃,and the sample injection volume of 25μL.The detection limit was 0.001 mg/L.The relative standard deviation was 0.23%～1.06%,and the recovery rate of domestic drinking water was 84.0%～99.1%.The certified reference material was in accordance with the requirements of the certificate.Comparing with cerium sulfate catalytic colorimetry and gas chromatography,ion chromatography does not require highly toxic reagents,complex pretreatment,and derivatization reaction.It belongs to a kind of green detection method. |
PDF Full Text Request