工作场所粉尘中游离二氧化硅测定方法的改进  

Improvements of the determination method for free silica in workplace dust

作　　者：何洪亮 李沙 王永风 杨颖 高亢 HE Hongliang;LI Sha;WANG Yongfeng;YANG Ying;GAO Kang(Department of Physical and Chemical Laboratory,Tianjin Xiqing District Center for Disease Control and Prevention,Tianjin,300112,China)

机构地区：[1]天津市西青区疾病预防控制中心理化检验科,天津300112

出　　处：《职业与健康》2024年第13期1778-1781,共4页Occupation and Health

摘　　要：目的通过对焦磷酸法测定粉尘中游离二氧化硅焦磷酸用量、稀释过程和过滤洗涤温度的改进,使焦磷酸法测定粉尘中游离二氧化硅的操作过程得到进一步优化,使测定过程影响因素明显降低,提高检测速度,从而保证结果及时准确。方法粉尘样品加入25 mL焦磷酸加热至245~250℃之间保持15 min,放置(60~80℃),倒入90℃热蒸馏水(150~200 mL)中,煮沸,趁热过滤,过滤后再用70~80℃、0.1 mol/L HCl洗涤。最后用70~80℃热蒸馏水洗到中性为止。电炉炭化,在800~900℃之间灰化,灰化后计算结果。结果使用25 mL焦磷酸使温度计的水银球能够全浸没在焦磷酸中使消化温度在245~250℃之间更方便操作,防止消化温度过高促使胶状物形成,影响下一步操作正常进行;放置(60~80℃),倒入90℃热蒸馏水(150~200 mL)中煮沸,此稀释过程易于操作,不易产生胶状物,避免了对下一步操作的影响;趁热过滤,过滤后再用70~80℃、0.1 mol/LHCl洗涤。最后用70~80℃热蒸馏水洗到中性,使过滤过程加快,缩短检测时间,提高工作效率。结论通过改变焦磷酸用量、稀释过程和过滤洗涤温度使测定过程得到进一步的优化,明显降低测定过程的影响因素,使测定速度明显加快,实验证明优化后的焦磷酸法可用于检测粉尘中游离二氧化硅含量。Objective By improving the pyrophosphate method for determining the amount of free silica pyrophosphate in dust,the dilution process,and the filtration and washing temperature,the operation process of pyrophosphoric acid method for measuring free silica in dust has been further optimized,so that the influence factors of the determination process are significantly reduced,and the detection speed is improved,so as to ensure the timely and accurate results.Methods Dust samples were heated with 25 mL pyrophosphoric acid to 245-250℃for 15 min,placed it at 60-80℃,poured it into 90℃hot distilled water(150-200 mL).Boil it,filter it while it was hot,and then wash it with 0.1 mol/HCl(70-80℃).Finally,washed with hot distilled water at 70-80℃until neutral.Electric furnace carbonization,ash between 800℃and 900℃,and calculate the results after ash.Results The use of 25 mL of pyrophosphoric acid allowed the mercury bulb of the thermometer to be fully immersed in the pyrophosphoric acid,making it easier to operate at a digestion temperature between 245 and 250℃,preventing the formation of jelly due to excessive digestion temperature and affecting the normal operation of the next step.Place(60-80℃)and pour it into 90℃hot distilled water(150-200 mL)to boil.This dilution process was easy to operate and does not produce gel like substances,avoiding the impact on the next step of operation.Filter while hot,and then wash with about 0.1 mol/L HCl(70-80℃).Finally,washed with hot distilled water at 70-80℃until neutral,accelerating the filtration process,shortening the detection time,and improving work efficiency.Conclusion By changing the pyrophosphoric acid dosage,dilution process and filtration washing temperature,the determination process can be further optimized,the influence factors of the determination process can be significantly reduced,and the determination speed can be significantly accelerated.The experiment proves that the optimized pyrophosphoric acid can be used to detect the free silica content in d

关 键 词：二氧化硅 温度 稀释 过滤 测定方法 改进 

分 类 号：R115[医药卫生—公共卫生与预防医学]