为避免其他因素导致总磷测定时的误差,确保总磷测定结果准确性,为科学改善水质提供高质量技术支撑.通过钼酸分光光度法(GB11893-1989)测定水中总磷的影响因素对比试验分析,研究水中总磷测定的主要影响因素,分别分析试剂、玻璃器皿的清洁程度、pH值、保存条件、显色条件对结果的影响.结果显示:钼酸分光光度法(GB11893-1989)测定水中总磷可用市售合格的溶液进行实验;玻璃器皿需用5％的硝酸浸泡并清洗干净;水样pH值对结果影响不大;样品采集后常温加酸保存,且在24 h内完成分析;显色时,温度应控制在20～30 ℃显色15～30 min,如果温度≤13 ℃,可以在20～30 ℃水浴显色15 min.
Study on Spectrophotometric Determination of Total Phosphorus in Water Quality With Ammonium Molybdate
In order to avoid errors in total phosphorus determination caused by other factors,the accuracy of total phosphorus determination results is ensured,which provides high-quality technical support for scientific im-provement of water quality.This paper conducts comparative experimental analysis on the influencing factors of total phosphorus determination in water using molybdic acid spectrophotometry(GB11893-1989),and studies the main influencing factors of total phosphorus determination in water.The impact of the cleanliness,pH value,stor-age conditions,and color conditions of reagents and glassware on the results is analyzed.The results showed that the molybdic acid spectrophotometric method(GB11893-1989)can be used to determine total phosphorus in wa-ter using commercially available qualified solutions for experimentation;Glassware needs to be soaked in 5％ni-tric acid and cleaned thoroughly;The pH value of the water sample has little effect on the results;Samples were collected and stored with acid at room temperature,and the analysis was completed within 24 h;When developing color,the temperature should be controlled at 20～30 ℃ for 15～30 minutes.If the temperature is≤13 ℃,the color can be developed in a 20～30 ℃ water bath for 15 minutes.
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