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Objective:This paper analyzed the operation of network laboratory and external quality control assessment of endemic arsenic disease laboratories at all levels in Guizhou Province, to provide reliable experimental quality assurance for evaluating the prevention and treatment effect and taking targeted intervention measure of endemic arsenic poisoning.Methods:The results of network operation and external quality control (arsenic in water, arsenic in urine) were statistically analyzed from 2008 to 2017. The assessment scope included the arsenic detection laboratory of provincial (1), municipal (1) and county level (2) which undertook endemic arsenic poisoning monitoring tasks.Results:From 2008 to 2017, 1 provincial laboratory for the determination of arsenic in water and urine was qualified. From 2011 to 2017, 1 municipal laboratory for the determination of arsenic in water and urine was qualified. From 2014 to 2017, 2 county level laboratories for the determination of arsenic in water and urine were qualified. From 2014 to 2017, the water and urinary arsenic in provincial, municipal and county laboratories had been continuously assessed as all qualified. The │Z│ values of water arsenic in provincial laboratories from 2008 to 2017 and urine arsenic from 2009 to 2017 were ≤2, and the results were satisfactory. The │Z│ values of arsenic in water after 2010 and in urine after 2011 in municipal and one county level laboratories were ≤2, which were all qualified and the results were satisfactory.Conclusions:The network laboratory of endemic arsenic disease in Guizhou Province operates well. The quality control of the laboratory and the results of external quality control of arsenic samples meet the quality requirements of the national laboratory, which can provide accurate and reliable test data guarantee for the continuous elimination of endemic arsenic disease.
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Objective@#To explore the application of new pretreatment technology of automatic electrothermal digestion instrument in the detection of arsenic in urine samples, in order to achieve rapid, convenient and accurate detection results.@*Methods@#Using wet digestion, an advanced sample preparation and digestion method (referred to as new pretreatment technology) was established by hydride generation-atomic fluorescence spectrometry (HG-AFS). Wet digestion: took 1.0 ml urine samples and put them into 10.0 ml corked scale digestive tubes, and added 0.20 ml sulfuric acid, 0.30 ml nitric acid and 0.50 ml hydrogen peroxide into the tubes successively. Shook solution and put them at AED-IV automatic electrothermal digestion instrument with 160 ℃ for half an hour, then heated up to 200 ℃ for 1 hour. It needed to be continually heated up to 260 ℃ and dissolved the solution until colorless transparent or light yellow. When the liquid level calm, and uniform reflux appeared, which meant the digestion finished, and then measured by atomic fluorescence photometer. At the same time, the new pretreatment technology was compared with the current standard (WS/T 474-2015) method, and the standard curve and linear range were calculated, as well as the detection line, precision and accuracy of the sample measurement.@*Results@#The new pretreatment technology could digest 60 samples per sample, which was superior to the current standard methods (20 samples) and reduced the amount of reagent used. There was no statistically significant difference between the two methods (P > 0.05). In the linear range of 0-100 μg/L, the correlation coefficient (r) > 0.999 3, the detection limit of the method was 0.066 μg/L, and the relative standard deviation (RSD) < 5%.@*Conclusions@#The new pretreatment technology is fast, efficient, environmentally friendly, economical, highly automated. The experimental result error is in a controllable range. It can be used for digestion of arsenic content in urine of different concentrations and has high applicability.
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Objective To explore the application of new pretreatment technology of automatic electrothermal digestion instrument in the detection of arsenic in urine samples,in order to achieve rapid,convenient and accurate detection results.Methods Using wet digestion,an advanced sample preparation and digestion method (referred to as new pretreatment technology) was established by hydride generation-atomic fluorescence spectrometry (HG-AFS).Wet digestion:took 1.0 ml urine samples and put them into 10.0 ml corked scale digestive tubes,and added 0.20 ml sulfuric acid,0.30 ml nitric acid and 0.50 ml hydrogen peroxide into the tubes successively.Shook solution and put them at AED-IV automatic electrothermal digestion instrument with 160 ℃ for half an hour,then heated up to 200 ℃ for 1 hour.It needed to be continually heated up to 260 ℃ and dissolved the solution until colorless transparent or light yellow.When the liquid level calm,and uniform reflux appeared,which meant the digestion finished,and then measured by atomic fluorescence photometer.At the same time,the new pretreatment technology was compared with the current standard (WS/T 474-2015) method,and the standard curve and linear range were calculated,as well as the detection line,precision and accuracy of the sample measurement.Results The new pretreatment technology could digest 60 samples per sample,which was superior to the current standard methods (20 samples)and reduced the amount of reagent used.There was no statistically significant difference between the two methods (P ＞ 0.05).In the linear range of 0-100 μg/L,the correlation coefficient (r) ＞0.999 3,the detection limit of the method was 0.066 μg/L,and the relative standard deviation (RSD) ＜ 5％.Conclusions The new pretreatment technology is fast,efficient,environmentally friendly,economical,highly automated.The experimental result error is in a controllable range.It can be used for digestion of arsenic content in urine of different concentrations and has high applicability.
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Objective To apply hydride generation atomic fluorescence spectrophotometry (HG-AFS method) in urinary arsenic detection,and to provide a better,newer and more convenient detection method for quantitative analysis of urinary arsenic.Methods According to the Guide to Develop Biological Sample Inspection Method(WS/T 68-1996) and Guide for Establishing Occupational Health Standards-part 5:Determination Methods in Biological Materials (GB/T 210.5-2008),HG-AFS method was established to detect arsenic content in urine after modification of the method for sample pretreatment,and to verify the linear range of standard curve and linearity,detection limit,precision,accuracy,stability of the sample,and to compare the experimental results of HG-AFS method with those of standard methods of WS/T 28-1996 and Determination of Arsenic in Urine by Cyanide Generation Atomic Fluorescence Method (WS/T 474-2015).Results The HG-AFS method linear range was from 0-100 μg/L,the correlation coefficient r =0.999 9,the detection limit was 0.07 μg/L,the precision was 1.96％-3.97％,and the recovery rate was 95.1％-105.0％.There was no statistical significance between HG-AFS method,the standard of WS/T 28-1996 or WS/T 474-2015 methods (t =1.539,0.353,all P ＞ 0.05).Conclusion The new method is superior to the current detection method owing to its low detection limit,high precision,good accuracy,and wide linear range.
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Objective To analyze the quality control measures on urinary fluoride testing in the implementation,and to provide experience in quality control for testing activities.Method According to the Determination of Fluoride in Urine-Ion Selective Electrode Method (WS/T 89-1996),focusing on ways to complete testing all the samples in a short time,implementing internal quality control measures in the testing before,during and after the implementation by different ways as blank experiment,standard substance detection,personnel parallel experiment,paralleled detection,instrument comparison and sample test repeat,were carried out.Results The test results of blank experiment were lower than the lowest detection limit;the test results of standard material were within the scope of the standard reference,there was no significant difference between the mean value and the reference value (t =0.01,0.00,0.02,all P ＞ 0.05),|Z| values were all less than 1;the results of personnel parallel experiment,paralleled detection,instrument comparison test results and sample test repeat were not significantly different statistically (all P ＞ 0.05);the results of instrument comparison and sample test repeat were not significantly different statistically (t =0.129,0.034,all P ＞ 0.05).A total of 9 123 urine samples were tested,the geometric mean of urinery fluoride was 0.58 mg/L.Conclusion Different quality control measures should be implemented through all the testing,control personnel errors,instruments,and reagents,etc,to ensure the quality of the entire test results.