钼酸铵分光光度法测定水质中总磷时砷的干扰消除研究

Study on Cancellation of Arsenic Interference in Determination of Total Phosphorus in Water by Ammonium Molybdate Spectrophotometry

中文关键词:  钼酸铵分光光度法  水质  总磷测定  砷干扰消除

英文关键词:ammonium molybdate spectrophotometry  water quality  total phosphorus determination  arsenic interference cancellation

中文摘要:

      采用单一影响因素和正交因素水平研究相结合，试验不同形态砷对钼酸铵分光光度法测磷过程的干扰、干扰的主要因素、硫代硫酸钠最佳加入量及最佳显色时间.结果表明不同形态砷的干扰强度依次是，五价砷[As(V)] 大于三价砷[As(III)]，而三价砷[As(III)] 又远远大于二甲基砷[DMAA].当As(V)浓度小于2.0 mg/L时，显色时间为测定的主要影响因素；当As(V)的浓度为0.1~5.0 mg/L时，考虑到操作以及实际水样中As(V)的含量等因素，选择硫代硫酸钠 0.5 mL(40 mg/mL)为最佳量，15 min为最佳显色时间.

英文摘要:

      The single affecting factor method is combined with the orthogonal test to study the interference of arsenic speciation and the main interference factor, and to determine the optimal amount of sodium thiosulfate and the best developing time in the ammonium molybdate spectrophotometric detection of total phosphorus in water. Results showed that the interference effects of arsenic species are: arsenate > arsenite >> dimethylarsinic. When the arsenic concentration is lower than 2.0 mg/L, the developing time is the main influence factor. When the arsenic concentration was in the range of 0.1~5.0 mg/L, the optimal amount of sodium thiosulfate (40 mg/mL) was 0.5 mL and the best developing time was 15 min with the consideration of the practical operation and real sample.