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Objective:To evaluate the detection ability of water fluoride of county-level laboratories in Shandong Province.Methods:From 2017 to 2019, Shandong Province organized 30, 30 and 37 county-level laboratories to participate in the national water fluoride external quality control assessment and the assessment results were evaluated by Z-ratio score method.Results:From 2017 to 2019, the feedback rate and qualified rate of water fluoride external quality control assessment of county-level laboratories were 100% (30/30, 30/30, 37/37) for three consecutive years.Conclusion:Over the past three years, the water fluoride detection ability of county-level laboratories in Shandong Province has been maintained at a satisfactory level.
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Objective:To analyze the assessment results of the external quality control and network operation of urinary iodine in local laboratories of Shandong Province, to evaluate the ability of consistent analysis.Methods:In 2016, there were 65 county-level urinary iodine laboratories participated in the provincial external quality control assessment, and there were 124 county-level urinary iodine laboratories participated in the national external quality control assessment in 2017. In 2018, all 137 county-level urinary iodine laboratories in the province participated in the national external quality control assessment. The testing results were analyzed with Z score method (qualified:│Z│≤2; basically qualified: 2 <│Z│ < 3; unqualified:│Z│≥3).Results:The 65 county-level laboratories in Shandong Province were evaluated in the provincial quality control test of urinary iodine in 2016, the feedback rate was 92.3% (60/65), the overall qualified rate was 81.7% (49/60); 124 county-level laboratories in Shandong Province were evaluated in the national quality control test of urinary iodine in 2017, the feedback and qualified rate were both 100.0% (124/124). All the 137 county-level laboratories were evaluated in the national quality control test of urinary iodine in 2018, the feedback and qualified rate were both 100.0% (137/137).Conclusions:The test abilities of urinary iodine in local laboratories of Shandong Province has been increasing continuously, and it has initially reached the detection level required for the full coverage of urinary iodine monitoring in all counties of the province.
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Objective To evaluate feasibility of a method for determining low and medium concentrations water iodine by an automatic iodine analyzer (hereinafter referred to as this method).Methods The low (0-10 μg/L)and medium (0-100 μg/L) concentrations water iodine were determined by an automatic iodine analyzer.Methodological experiments were carried out on this method,including standard curve linearity,detection limit,precision experiment,standard recovery experiment,and standard substance determination.Results The absolute values of the linear correlation coefficients of the low and medium concentrations standard curves were ＞ 0.999 0,and the detection limits were 0.32 and 2.60 μg/L,respectively.Precision:the coefficient of variations were all below 2％ (n =18) of low,medium and high iodine concentrations water samples in the range of low and medium concentrations water iodine,and the average recovery rates were 100.7％ and 101.1％ (n =6),respectively.The determination results of the water iodine standard substance GBW 09113d and GBW 09114d were (8.3 ± 0.3)and (61 ± 2) μg/L (n =6),respectively,which were within the given standard values range.Conclusions This method has higher precision and accuracy,less reagent consumption,less time consumption,and simple operation.It is convenient for large-scale detection,and has strong applicability.
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Objective To evaluate a method for determining the iodine content in urine by an automatic iodine analyzer.Methods The iodine content in urine was determined by an automatic iodine analyzer.Methodological experiments were carried out on the method (including test standard curve linearity and detection limit,precision test,spike recovery test,standard substance determination experiment,method comparison test).The urine samples from the method comparison were obtained from 27 pregnant women collected from Nantantou Village,Baoshan Street,Licheng District,Jinan City,Shandong Province.and the results of the same samples were compared with the results determined by arsenic-cerium catalytic spectrophotometry (GB method).Results The absolute value of correlation coefficient of the mass concentration range (0-300 pg/L) standard curve was ＞ 0.999 0,the detection limit was 2.9 μg/L (the sample volume was 0.25 ml).Precision:the coefficient of variations of the three iodine concentrations in the range of low,medium and high were 3.8％,3.1％,2.3％ (n =18),respectively.Accuracy:the average recoveries were 98.8％,99.5％,101.2％ of low,medium and high urine samples in the range of curves (n =6),and the total average recovery was 99.8％.The measurement results of two urinary iodine standard substance were in the standard value range.Methods comparison experiment:there was no significant difference between the results of 27 urine samples measured by two methods (t =0.40,P ＞ 0.05).Conclusions The method of automatic iodine analyzer in detection of urinary iodine has higher precision and accuracy,less reagent dosage,and simple operation.It is suitable for detection of large quantities of urinary iodine samples.
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Objective To investigate the status of iodine content in the inner and outer environment of residents in excessive iodine intaking areas in Liaocheng of Shandong Province after stop taking iodized salt.Methods Totally 300 residents from each county (city) were selected for semi-quantitatively examination of their household salt in seven excessive iodine intaking counties (cities) in 2015 and 2016.Five counties were surveyed in 2015,and two other counties were surveyed in 2016.Then one town was selected from every county (city) as test site,one hundred children aged 8-10 (50 males and 50 females) from every test site were selected to measure their household salt iodine level.If the household salt was confirmed a non-iodized salt,water samples and urine samples were collected.Water iodine and urinary iodine contents were measured by arsenic cerium catalytic spectrophotometry (WS/T 107-2006).Results In 2015 and 2016,non iodized salt rates were 97.4％ (1 753/1 800) and 96.6％ (1 738/1 800),respectively in Liaocheng.Totally 686 household drinking water samples were measured.The water iodine levels were 2.7-748.4 μg/L,and the median was 203.4 μg/L.Totally 699 urine samples were measured.The urine iodine levels were 33.6-1 692.0 μg/L,and the median was 486.8 μg/L.The median of children's household water iodine level and median of children's urinary iodine level were significantly positively correlated (r =0.857,P ＜ 0.05).Conclusions The measurement of stop taking iodized salt in excessive iodine intake areas in Liaocheng is well implemented.Some monitoring sites show significant improvement.However,the urine iodine level of most residents is still high.The harmful effects of excessive iodine intaking are still constantly existed in some areas.In the future,in addition to continue to change the water to reduce iodine,it is also necessary to strengthen the health education of residents to improve the residents' awareness of the dangers of excessive iodine.
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Objective To establish a rapid, simple and accurate method for detection of selenium in grain that is suitable in Chinese situation. Methods Nitric acid and perchloric acid(7: 3, v/v) were used to digest the grain samples by heating on a hot plate. Selenium was determined with hydride generation atomic fluorescence spectrometry. Sample detection limit, precision, accuracy(recovery, method characteristics and method control) were studied. And the grain samples of Shandong Province were determined by this method. Results The lowest detection limit was 4 μg/kg. The coefficient of correlation of working curve was 0.999 9. Intra-day precision was 1.32%, day precision was 4.17%. The total average rate of recovery was 100.5% with a range of 96.7% - 105.5%, and the average rates of recovery were 104.0%, 99.0% and 98.4% (n = 6). The determination results of corn reference material [(0.022 ± 0.006) mg/kg] were in the standard value range [(0.021 ± 0.008) mg/kg]. The determination results of the samples [(0.424 ± 0.096) mg/kg] were consistent with the results of national standard fluorescence method [(0.406 ± 0.108) mg/kg]. The contents of selenium in wheat, maize and sweet potato samples from five regions of Shandong Province were:Shanting:(0.030 3 ± 0.025 2),(0.016 8 ± 0.013 5),(0.015 4 ± 0.002 9) mg/kg; Anqiu:(0.020 3 ± 0.000 1), (0.020 4 ± 0.009 9), (0.017 1 ± 0.007 5) mg/kg; Ju'nan:(0.021 3 ± 0.013 9), (0.018 5 ± 0.007 8),(0.019 9 ± 0.003 6)mg/kg;Yishui:(0.025 7 ± 0.006 2),(0.020 6 ± 0.003 2), (0.018 2 ± 0.003 2) mg/kg; Wulian:(0.020 3 ± 0.004 7), (0.020 1 ± 0.008 9), (0.018 4 ± 0.007 3) mg/kg. Conclusions The method has the advantages of higher precision and accuracy, less time, less pollution, less aciduse, easier operation and repeatability.It is very suitable for measuring selenium content in large amount of food samples.