金屬加工油霧滴採樣分析方法之研究

A Study of Measurement Method for Oil Mist from Metalworking Fluids

在金屬加工切削作業過程時會產生油霧滴，如勞工長期吸入將引發呼吸道發炎、肺炎及肺癌等職業疾病。目前我國尚無作業場所空氣中之油霧滴採樣分析參考方法公告，而本研究目的係針對金屬加工過程產生油霧滴之採樣分析方法進行技術開發研究。研究方法主要依英國HSE MDHS 84及美國NIOSH 5524採樣分析方法進行研究，對各種金屬加工液，以重量分析方法及使用環己烷當萃取溶劑去評估採樣部分（萃取回收率及樣本儲存穩定性）及分析部分（偵測下限、可量化最低量及分析變異係數）之可信度。研究結果發現對7家廠商所提供的13個金屬加工液進行萃取回收率測試時，其萃取回收率為0.53 ~ 0.98，在油性金屬加工液其萃取回收率多達0.9以上，且相較於水溶性金屬加工液其分析之變異性亦較低，分析變異係數值多數在5%以下。在3種油性樣本儲存穩定性測試時，其儲放穩定性大致可達28天，其它水溶性金屬加工液其28天儲放穩定性則較差，無法達80%萃取回收率。雖然HSE MDHS 84建議方法只用在黏度大於18 cSt（或mm^2/s）@40 ℃條件下的金屬加工液，但本研究發現，部分黏度在12-17 cSt的油性金屬加工液，樣本回收率及儲存穩定性分析結果亦可符合我國方法驗證要求，故本研究建議後續在進行方法適用性判斷時，建議應先取得原料加工液進行添加測試，以確認萃取回收率範圍，萃取回收率在90%左右的油性金屬加工液，其分析變異係數值普遍可符合我國方法驗證要求，即適用本研究分析方法。

Oil mist will be generated during metal machining. If workers inhale oil mist for a long time, it will cause occupational diseases such as respiratory inflammation, pneumonia and lung cancer. There is no air sampling and analysis method for oil mist at workplaces in Taiwan now. The purpose of this study is to develop a measurement method of oil mist from metalworking fluids at workplaces. This research method was mainly derived from UK HSE MDHS 84 and US NIOSH 5524 method. For various metalworking fluids, gravimetric analysis methods and cyclohexane as the extraction solvent was conducted to evaluate the reliability of sampling(recovery and storage stability of samples) and analysis(Limit of Detection(LOD), Limit of Quantitation(LOQ) and analysis Coefficient of Variation (CVa)). The results found that the recoveries of 13 metalworking fluids provided from 7 factories were 0.53 to 0.98, and ones for oil-based metalworking fluids were as high as 0.9 or more. In comparison of CVa, oil-based metalworking fluids' values were lower than water-soluble ones, and their values were mostly below 5%. On evaluation of storage stability of samples for three mineral oil-based metalworking fluids , their stability were approximately 28 days, while the other water-soluble metalworking fluids had poor stability (28 days) and could not reach 80% recovery. Although the MDHS 84 method is recommended for metalworking fluids with a viscosity greater than 18 cSt (or mm2/s) @ 40℃, this study found that for some oil-based metalworking fluids with a viscosity in the range of 12-17 cSt, its recovery and storage stability of samples can also meet Taiwan's method verification requirements. Therefore, this study recommends that metalworking fluids should be sampled for testing to confirm recoveries whether judging the applicability of this method. If recovery of the oil-based metalworking fluid is more than 90%, the analysis coefficient of variation meets the requirements of Taiwan's method verification, and this analytical method is applicable.