粉尘中游离二氧化硅测定过程探讨  

Discussion on the determination process of free silica in dust

作　　者：吴雪梅[1] 兰红军[1] 黎少映 冯耀基[1] WU Xue-mei;LAN Hong-jun;LI Shao-ying;FENG Yao-ji(Clinical Laboratory,Nanhai District Center for Disease Control and Prevention,Foshan,Guangdong 528200,China)

机构地区：[1]广东省佛山市南海区疾病预防控制中心检验科,广东佛山528200

出　　处：《中国卫生检验杂志》2020年第7期802-804,共3页Chinese Journal of Health Laboratory Technology

摘　　要：目的通过对焦磷酸法测定粉尘中游离二氧化硅中试剂、温控和过滤等因素的改进,优化焦磷酸法测定粉尘中游离二氧化硅的过程,保证结果的准确性。方法粉尘样品加入20 ml焦磷酸在245℃~250℃消化20 min,加热蒸馏水(50℃~80℃)稀释至150 ml^200 ml。取慢性定量滤纸(Whatman grade 42)过滤后再用0.1 mol/L HCl洗涤。最后用热蒸馏水洗到中性为止。恒重后用重量法计算结果。结果粉尘样品的结果在≤10%和10%~50%时,焦磷酸体积和消化时间的增加对样品的结果差异无统计学意义(P>0.05)。而当样品≥50%时,焦磷酸体积和消化时间的增加对样品的结果差异有统计学意义(P<0.05)。滤纸A和B的透率分别为7.96%和6.76%,滤纸C的透率为0.83%。结论优化后的焦磷酸重量法,避免了样品稀释过程中胶体的产生,解决了消化试剂用量和消化时间不足导致的结果偏高。选用更优质的滤纸减少了样品粒度过细时透滤带来的误差,优化后的测定方法准确性更高。Objective To improve the reagent,temperature control and filtration of pyrosilic acid method to determine free silica in dust,optimize the process and thus ensure the accuracy of the results.Methods 20 ml pyrophosphate was added into the dust samples,then digested at 245℃-250℃for 20 min,and diluted to 150 ml-200 ml with distilled water(50℃-80℃),filtered with chronic quantitative filter paper(Whatman grade 42),washed with 0.1 mol/L HCl.Finally,the samples were washed with warm distilled water until neutral.The results were calculated by the gravimetric method after constant weight.Results When the results were≤10%or of 10%-50%,the increase in pyrophosphate volume and digestion time had no statistical significance on the difference in the sample results(P>0.05).When the results was≥50%,the increase in pyrophosphate volume and digestion time had statistical significance on the differences in the sample results(P<0.05).The transmittances of filter papers A and B were 7.96%and 6.76%,and the transmittance of filter paper C was 0.83%.Conclusion The optimized pyrophosphoric weight method avoids the formation of colloids during the sample dilution.It solves the problem of the higher results because of the lack of digestive reagents and digestion time.The better filter paper reduces the error caused by diafiltration when the sample size is too fine,and the optimized measurement method is more accurate.

关 键 词：游离二氧化硅 焦磷酸法 粉尘 

分 类 号：R134.4[医药卫生—劳动卫生]