不同異氰酸鹽類採樣器的採樣效果比較研究

本研究以標準氣體產生器產生固定濃度的異氰酸鹽（2,6-toluene diisocyanate,2,6-TDI、2,4-toluene diisocyanate,2,4-TDI與1,6-hexamethylene diisocyanate,HDI），並利用包覆型濾紙採樣匣（收集總二異氰酸鹽）、兩片式雙層濾紙採樣匣及三片式雙層濾紙採樣匣（同時收集氣態與氣膠態二異氰酸鹽）同時進行採樣分析，目的在比較三種採樣器於不同採樣條件（流量、環境溼度與採樣時間）下的採樣結果。本研究所使用的裱敷試劑為1-（2-pyridyl）piperazine（1,2-PP），經採樣衍生後，以HPLC/fl uorescence detector進行分析。研究結果顯示，三種採樣器之最佳採樣條件為：採樣流量1.0 L/min，環境濕度25%，採樣時間15分鐘以下，且以包覆型濾紙採樣匣所捕集到氣態或總異氰酸鹽的濃度為最高，兩片式採樣匣次之，三片式採樣匣最低。若以最佳採樣條件為基準，當流量增加為2.0L/min時，發現三種採樣器所捕集到總異氰酸鹽的濃度與其結果相比約有高達60%以上的損失；而當濕度增加為80%、時間延長至60分鐘時則有高達80%的損失。由上述結果可知，在高流量、高濕度與長時間的採樣下，三種採樣器的捕集效率皆會顯著降低。此外，在最佳條件下，比較兩片式與三片式採樣匣的捕集結果，發現兩片式所採集到氣態與氣膠態濃度皆較三片式高。但當採樣流量從0.5 L/min增加至2.0 L/min，濕度從25%增為80%、時間由15分鐘延長至60分鐘時，則兩種採樣器的氣膠濃度皆明顯減少99%以上。因此，就總異氰酸鹽的濃度而言，在不同採樣條件下，均以包覆型濾紙採樣匣所捕集的濃度最高，但此採樣器的缺點是無法將氣態與氣膠態濃度分開。而兩片式與三片式雖能有效將氣態與氣膠態分開，但在高流量、高濕度與長時間採樣下，氣膠濃度會被明顯低估，故在作業環境現場量測時，建議使用包覆型濾紙採樣匣採集總異氰酸鹽並搭配兩片式雙層濾紙採樣匣來捕集氣態與氣膠態之濃度，同時將採樣時間儘量縮短，以反應作業現場實際濃度，作為異氫酸鹽類相關作業場所危害控制之參考。

關鍵字

異氰酸鹽類；包覆型濾紙採樣匣；兩片式雙層濾紙採樣匣；三片式雙層濾紙採樣匣

並列摘要

This study aimed to analyze isocynates sampling efficiencies of three different samplers - close-face, 2-piece and 3-piece filter cassettes. All conditions affected sampling efficiencies of those three samplers were performed, including flow rate, moisture and sampling time. The 2,4-TDI, 2,6- TDI and HDI were produced by standard gas generator and the fi lters were coated by 1-(2-pyridyl) piperazine(1,2-PP). After derivatization, samples were analyzed by HPLC with fluorescence detector. This investigation found the optimal sampling condition of all types of samplers was as follow: sampling flow rate was 1.0 L/min; moisture was 25%, and sampling time was 15 min. Close-face filter cassette performed the optimal efficiency of collecting 2,4-TDI, 2,6-TDI and HDI, either aerosol or gas type, followed by 2-piece filter cassette, the 3-piece filter cassette was the worst. The results also indicated higher flow rate, moisture and longer sampling time would decrease the sampling efficacy. This study confirmed that close-face filter cassette performed the best capture capability, although it could not separate gas and aerosol type of isocynates. 2-piece and 3-piece filter cassettes could separate gas and aerosol isocynates, but they would greatly underestimate the aerosol isocynates at high flow rate(2.0 L/min), high moisture(80%) and long sampling time(60 min). Consequently, this investigation suggested utilizing the close-face filter cassette to determine the total isocynates and the 2-piece filter cassette to measure the gas and aerosol isocynates in working field. The short sampling time was necessary to reflect the real concentration.