Verification of an improved method for determination of urinary iodine by As3+-Ce4+ catalytic spectrophotometry / 中国地方病学杂志

ABSTRACT

Objective To verify the feasibility and application value of an improved method for determination of urinary iodine by As3+-Ce4+ catalytic spectrophotometry.Methods Adults urine samples were collected,iodine calibration curves of 0-300 μg/L and 300-1200 μg/L were prepared,and urinary iodine was determined by the improved As3+-Ce4+ catalytic spectrophotometric method.Lyophilized human urinary iodine ingredient standards were used to validate linearity and range,limit of detection,precision and accuracy of this improved detection method.Results The linear range of the calibration curve was 0-300 μg/L,the detection limit was 1.8 μg/L,and the range of correlation coefficient was-0.9995--0.9997.When measuring urinary iodine at 40-80,100-149,200-280 μg/L,the relative standard deviations were 1.5％,0.8％ and 0.5％.When measuring urinary iodine at 40-80,100-149,150-180 μg/L,the average recoveries were 97.8％,99.8％ and 96.6％.Two given values of urinary iodine of national standard samples were (73.0± 9.0) and (206.0± 10.0)μg/L,and the results determined by this method were (75.5 + 0.9) and (207.5 ± 1.9)μg/L,and the relative deviation was 3.4％ and 0.7％,respectively,the results determined were all within the given value range.The linear range of the calibration curve was 300-1200 μg/L,the detection limit was 305.2 μg/L,the range of the correlation coefficient was-0.9996--0.9999.When measuring urinary iodine at 300-400,500-600 and 1000-1200μg/L,the relative standard deviations were 0.6％,1.0％ and 0.7％.When measuring urinary iodine at 300-499,500-599 and 600-700 μg/L,the average recoveries were 99.7％,99.2％ and 100.4％.Two given values of urinary iodine of national standard samples were (558.3 ± 3.5) and (884.8 ± 4.7)μg/L,the results determined by this method were (556.0 + 17.0) and (883.0 ± 28.0)μg/L,and the relative deviation was 0.4％ and 0.2％,respectively,the results were all within the given value range.Conclusions This method extends the detection range of iodine concentration,and improves precision and accuracy.This method greatly reduces the amount of arsenic used therefore reduces environmental pollution,which is suitable for promotion.