RESUMO
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.
RESUMO
Objective To establish information management systems of drinking water defluoridation project in water-related endemic fluorosis areas and investigate the status of drinking water defluoridation project in Liaoning, provide the basis for the development of control measures. Methods Global positioning systems (GPS)and geographic information systems(GIS) were used in the study in August 2006 - July 2008. Water defluoridation projects of 1234 in 48 counties(cities, districts) in drinking water type of fluorosis areas were positioned. Latitude and longitude, water samples, water fluoride content were collected or tested. GIS was used to establish information management system of water defluoridation projects. Results We have established information management system for the facilities of decreasing water fluorine in drinking water type of endemic fluorosis regions in Liaoning. One thousand two hundred and thirty four defluoridation facilities distributed in east longitude between 39.39° - 43.37°,north latitude between 119.25° - 125.50°, and altitude between - 6.60 and 801.14 meter in 48 endemic fluorosis counties in 13 cities. Nine hundred and twenty seven facilities for decreasing fluorine were able to supply water regularly, accounting for 75.1% of investigated projects;29 facilities was .not yet completely rebuilt, accounting for 2.4%;278 facilities(supply water for 344 villages) were out of order or discarded for 22.5% of investigated projects.Water fluorine contents of 63 facilities were greater than 1.2 mg/L, accounting for 6.8% of investigation project.Facilities working regularly and water fluorine was in accord with hygienic standard for drinking water facilities were 70.0%. Conclusions The establishment of Liaoning province defluoridation project information management system in the whole province of drinking water type of fluorosis areas provides scientific basis for accurate decision-making on prevention and control of the disease.