亨利常數(KH; M atm-1)對於探討化學物質於環境中的分布及宿命為一重要的參數。本論文使用一自製吹氣捕捉系統,利用銨離子(NH4+)於鹼性環境下會轉變成氨(NH3(g))的特性,搭配離子層析儀及鄰苯二甲醛(OPA)螢光衍生法量測氨於1 M氫氧化鈉濃度時溫度範圍在283323 K之KH,並與先前於0.1及10 M氫氧化鈉濃度時所量測的結果作比較,發現隨著離子強度增加會因產生鹽析反應而使所量測之KH變小,利用Setschenow方程式修正可得到25oC離子強度可忽略時氨的KH為50 M atm-1;40oC時氨的KH為19 M atm-1。同時氨在含有1M氫氧化鈉濃度時的KH對溫度T(K)的關係為log KH=-6.36+2352.7/T,T為283323 K。此系統並嘗試利用OPA螢光衍生搭配高效液相層析儀(HPLC)應用於同時量測C2-C9 一級脂肪胺的亨利常數。
The Henry’s law constant (KH; M atm-1) plays an important role on the study of the distribution and the fate of chemicals in the environment. In principle ammonium ion (NH4+) becomes gaseous ammonia (NH3(g)) in aqueous solutions at alkaline environment. The Henry’s law constant of ammonia in 1 M sodium hydroxide (NaOH) over a temperature range of 283323 K can be precisely determined using a homemade purge-and-trap system with ion chromatography and o-phthaldialdehyde (OPA) derivatization fluorescence as analysis method. The results were also compared with KH previously measured in 0.1 and 10 M NaOH and showed that the values of KH of ammonia decreased with increased ionic strengths of solution as a result of salting-out effect. The corrected experimental KH in deionized water was 50 M atm-1 at 298 K and 19 M atm-1 at 313 K by using Setschenow equation. The relation of KH with temperature was described by the equation: log KH= -6.36+2352.7/T, T= 283323K. This system could also be applied to measure KH of C2-C9 primary amines simultaneously by using OPA derivatization HPLC with fluorescence detection.