二異氰酸甲苯及二異氰酸二苯甲烷採樣分析技術研究

Sampling and analysis of airborne TDI and MDI

本研究以裱敷1mg 1-（2-pyridyl）piperazine （1,2-PP）的玻璃纖維濾紙進行二異氰酸甲苯（Toluene diisocyanate, TDI）及二異氰酸二苯甲烷（Methylene bisphenyl isocyanate, MDI）之採樣，以acetonitrile / dimethyl sulfoxide （90：10）脫附，再以HPLC/螢光偵測器進行分析。研究結果顯示，本分析方法的檢量線線性範圍在2,4-TDI及2,6-TDI為28 ng/mL至557 ng/mL；MDI為86.8 ng/mL至1736 ng/mL 。若以15 公升的空氣捕集量，換算為原來空氣中2,4-TDI及2,6-TDI濃度則從3.7μg/m3至73 μg/m3；MDI濃度為11.6μg/m3至231.5 μg/m3，均涵蓋我國的法定標準（2,4-TDI 最高容許濃度為35μg/m3，MDI 最高容許濃度為200μg/m3）。本方法之分析變異係數在2,4-TDI、2,6-TDI及MDI分別為2.3％、3.1％及1.9％ （N=6）；偵測極限分別為1ng/mL、3ng/mL及14ng/mL。三者的脫附效率分別為108.4%、104.3%及106.4%，捕集效率在2,4-TDI及2,6-TDI分別為89.35%及94.33%。無論是裱敷濾紙或樣品濾紙，以室溫遮光或冰箱冷藏（4℃）保存，均可穩定至少28 天且偏差小於10%。本研究方法適合作為我國作業現場TDI及MDI短時間暴露濃度標準之測定方法，並已克服過去現場採樣分析上之困難。

A sensitive high-performance liquid chromatography (HPLC)-fluorescence detection method for the determination of toluene diisocyanate (TDI) and methylene bisphenyl isocyanate (MDI) is described. Glass fiber filters coated with 1mg of 1-(2-pyridyl)piperazine (1,2-PP) are employed to collect airborne TDI and MDI. After the air sampling, the filter is extracted with 90/10(v/v) acetonitrile / dimethyl sulfoxide. Result shows that the linear dynamic ranges are from 28 to 557 ng/mL for 2,4-TDI and 2,6-TDI and from 86.8 to 1736 ng/mL for MDI. The corresponding air concentrations are from 3.7 to 73 μg/m3 for 2,4-TDI and 2,6-TDI and from 11.6 to 231.5 μg/m3 for MDI based on a 15 liters air sample. Result also indicates that the analysis coefficients of variation (N=6) are 2.3%, 3.1% and 1.9%, and the extraction efficiencies are 108.4﹪,104.3﹪,106.4﹪,respectively, for 2,4-TDI, 2,6-TDI, and MDI. The detection limits for the three compounds are 1ng/mL, 3ng/mL and 14ng/mL, respectively. The sampling efficiencies of 2,4-TDI and 2,6-TDI are 89.35 ﹪and 94.33﹪. The coated filters are found stable for at least 28 days after collection of samples, with error less than 10﹪, irrespective to sample storage in room temperature or in a refrigerator. This method is recommended to be use for the analyses of short-term exposure level of TDI and MDI in the field.