A method for determination of iodine in water by flow injection catalytic spectrophotometry with no needs of highly toxic arsenic reagent / 中华地方病学杂志

ABSTRACT

Objective To establish a catalytic spectrophotometric method for determination of iodine in water without the use of highly toxic arsenic reagents with good precision and accuracy.Methods A new flow injection catalytic spectrophotometry method for determination of iodine in water was established by combining flow injection analysis (FIA) with a new catalytic spectrophotometry for determination of iodine with no need of arsenic reagent.The standard curve linearity,sample detection limit,precision and accuracy of different iodine content ranges (0-250,0-1 200 μg/L) were tested.The test result was compared with that of the arsenic-based catalytic spectrophotometry recommended by the iodine deficiency disorders monitoring program in China (recommended monitoring method).Results A calibration relation of C =aA2 + bA + d (Ciodine concentration,Ameasuring absorbance peak area from FIA) of the new method existed in the range of 0-250 and 0-1 200 μg/L.The linear correlative coefficient were both 0.999 9.The detection limit for iodine in water was 0.3 μg/L.The FIA peak shape of the sample tube with the lowest content is determined,and the sensitive iodine signal is detected.The water samples with different iodine content ranges were determined in parallel for 6 times,and the coefficient of variation (CV) was 0.2％-2.7％;the recoveries ranged from 95.0％ to 105.0％,and the total average recovery was 100.3％.The measured values of water iodine standard material GBW 09113e [(8.2 ± 1.2) μg/L] and GBW 09114d [(62.0 ± 6.0) μg/L] in the standard curve of different iodine contents were all within the uncertainty range of the given value.There was no significant difference between the results of recommended monitoring method and the new method (t =0.781,P ＞ 0.05).Conclusions The new method for measuring water iodine has a wide standard curve range,high sensitivity,and good precision and accuracy.The instrument is easy to operate,and no need for toxic arsenic reagent.The method is a reliable method for water iodine detection.