以固相微萃取技術為基礎採樣分析空氣中甲醛的應用

Abstract

甲醛為反應性高之化學物質，廣泛地應用於工業界與醫療界，過度暴露可導致眼鼻及呼吸系統不適之急性反應，長期暴露下則可能有致癌之發生，因此倍受關心。 本研究乃利用固相微萃取裝置 (Solid-phase microextraction, SPME)對甲醛進行採樣與分析。選用之纖維材質為65 μm之Poly (dimethysiloxane)-divinylbenzene (PDMS-DVB)，配合SPME裝置，分別利用裸露與內縮 (擴散徑長z = 0.3 cm) 兩種不同方式採集氣相甲醛以及藉由拜香系統所產生氣粒相共存之甲醛。在採集氣相甲醛部份，設定不同的濃度、溫度、相對溼度與採樣時間，並配合GC/FID進行分析；在採集氣粒相共存之甲醛，則設定固定之系統流量與不同採樣時間，同時以XAD-2吸附管作為傳統方式之驗證。 在標準氣體所做的結果顯示，不論以裸露採樣或是內縮採樣，其甲醛的吸附質量均與濃度以及採樣時間呈線性關係。溫度(15°C-35°C)以及相對溼度(25%-80%)在內縮採樣上看不出明顯的影響，而裸露採樣則有明顯的影響。溫度對裸露採樣之採樣率的變異貢獻佔68.91%，而相對溼度則貢獻19.63%。而在內縮採樣上則以濃度(貢獻度為36.28%)與採樣時間(貢獻度為27.89%)為主要影響其採樣率之因子。 而在採集拜香燃煙方面，可發現無前置濾紙所採集到之甲醛吸附量高於有前置濾紙之結果。無前置濾紙之甲醛吸附量與時間呈現一曲線關係，而有前置濾紙之甲醛吸附量則與時間呈一線性關係。就化學物種之分析而言，無前置濾紙所採集到的物種也較為複雜，推測SPME纖維可採集到微粒上之甲醛，且同時可採集到其他由拜香所產生之物質。

Formaldehyde is a high reactive compound commonly used in industry and medical treatment. Exposure to formaldehyde results in acute effect on upper respiratory tract and possible carcinogeness. In this study, formaldehyde was sampled by derivation with o-(2, 3, 4, 5, 6 pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA) coated on 65 μm of poly (dimethylsiloxane)/divinylbenzene solid-phase microextraction fibers. Two types of sampling mode, fiber extruded outside the needle and fiber retracted inside the needle, were carried out. A standard gas generation system regulated the concentration of formaldehyde, temperature and humidity in an exposure chamber. A kind of Chinese incense was burned in incense combustion system where flow rate was regulated at 3Lpm. The NIOSH-2451 active sampling method with XAD-2 was used for validation of the SPME method. To sample analytes, thermal desorption incorporated with gas chromatography with flame ionization detector was used. The amount of formaldehyde collected on fibers, either in extruded mode or retracted mode, is well correlated with the concentration of formaldehyde and sampling time. Temperature (15°C-35°C) and humidity (25%-80%) did not significantly affect the performance of the retracted fibers, but did affect that performance of the extruded fibers. The variation of sampling rate was mainly attributed to temperature by 68.91% and humidity by 19.63% while fibers were used in the extruded mode. And when the fiber was used in the retracted mode, concentration (36.28%) and sampling time (27.89%) both attributed to the variation of sampling rate. To sample incense smoke, the amount of formaldehyde collected by the extruded fibers without prefiltration was higher than that with prefiltration. The relationship between mass and sampling time was nonlinear for the samples without prefiltration, but it was linear for the samples with prefiltration. Besides, compounds collected in the former were more complicate. It suggests that compounds in addition to particulate–bonded formaldehyde from burning Chinese incense would be sampled by the PFBHA coated PDMS/DVB fiber.