工業衛生實驗室粉塵重量分析能力比試樣品製備

Preparation of Dust Weighing Samples for Proficiency Analytical Testing Program

粉塵重量分析為國內勞工作業環境空氣中有害物分析能力比試新增加的類別，由於國內外目前並沒有既方便且經濟之粉塵重量分析類樣品製備方法可供參考，因此本研究開發粉塵標準樣品的製備方法。其配製方式是懸浮鈉鈣石灰標準玻璃顆粒（soda lime glass，SLG）於60／40比例之水／乙醇溶液添加於聚氯乙烯濾紙上，再經抽氣過濾及乾燥箱去溼製備而成。在進行粉塵樣品配製前，濾紙必須先經過篩選以控制整組濾紙的稱重組距小於粉塵添加重量的15％。水和乙醇混合液中乙醇之功用在讓鈉鈣石灰標準玻璃顆粒於溶液中成為均勻的懸浮狀態且使溶液易於通過聚氯乙烯濾紙。經測試，粉塵樣品於郵寄過程所造成的重量損失小於0.3％。於四次分析能力比試中參加粉塵類比試的實驗室家數約有26家，其分析結果的回報數據經統計分析，其相對標準偏差皆在1％以下，從以上的數據顯示，以此方法進行粉塵類分析能力比試樣品的製備可以很成功的得到很均一的樣品。

Dust is a new category of test samples in workplace contaminant Proficiency Analytical Testing (PAT) program in Taiwan. Since there is no reference method to generate dust samples conveniently and economically, a method to prepare dust samples by pipetting 60/40 water/ethanol solution of 2μm soda lime glass particles onto polyvinyl chloride (PVC) filters was developed. Before dust samples were pipetting onto filter, filters should be prescreened to have uniform weight with a deviation of 15% of the weight of loaded glass particles. The dust weight of every sample batch is around 1 to 2 mg. Ethanol was utilized to homogeneously suspend glass particles in the solution and accelerate the filtration rate of the dust sample through the suction system. The analyses coefficient of variance (CV) for 40 quality control testing samples was less than 1.0%. The sample loss due to mailing process was found less than 0.3%. A testing set containing four PAT samples were sent to 26 laboratories, and the average CV was less than 1.0%. Results indicated this method can be successfully utilized to prepare homogeneous standard dust samples for PAT program.