進一步改良吹氣捕捉系統搭配離子層析儀量測高鹽度樣品中銨離子濃度

Further Improvement of Purge-and-Trap Ion Chromatography for the Determination of Ammonium Ion in High-Salinity Samples

林宗儀(HASH(0x1c861de0))

指導教授 ： 吳劍侯

國立清華大學/原子科學院/生醫工程與環境科學系/碩士(2008年)

摘要

吹氣捕捉( Purge and trap )技術常被廣泛應用於含有複雜基質的樣品前處理系統。利用吹氣捕捉前處理系統，可以先將銨離子與高鹽度的基質有效地分離，再利用離子層析儀( Ion chromatography )量銨離子濃度。本論文主要目的為改善前處理系統穩定性與提升系統吹除效率，並以雙膜層理論( Two-film theory )為基礎，發展出前處理系統之傳輸理論模型，進而求得氨的亨利常數對溫度的關係式。
探討影響吹氣捕捉系統之吹除效率之變因有：加入的氫氧化鈉濃度、吹除瓶液面的高度、氣體種類、吹除流速、吹除時間以及系統的溫度等。經過改良後的出垂捕捉系統在最佳參數條件下進行實驗，所得到的吹除效率可以從65 %提升至90 %，且其背景值由原先的40 ~ 60 ppb降低至20 ppb以下，使得在低濃度的量測上更具可信度。

關鍵字

銨離子 ； 亨利常數 ； 吹氣捕捉 ； 離子層析

並列摘要

Purge and trap system is often widely applied to the pretreatment of the sample in complicated matrix. With purge and trap system, the ion, NH4+(aq), separated from the concentrated salt solution would be injected to the ion chromatography for analysis. In this study, we improved the efficiency of the purge and trap system and stability. In addition, we developed the theoretical model of the purge and trap system based on the two-film theory. What is more, we utilized this model to obtain the relation between the Henry’s law constant of NH3 and temperature.
The parameters which affect the efficiency of the purge and trap system include the concentration of NaOH, the height of liquid of purge vessel, type of gas, flow rate, purge time and the temperature of the system. With the improved pretreatment system, the efficiency could be raised from 65 % to 90 %, and the signal of the blank decreased to lower than 20 ppb which is one-third of the original system. It was convinced of the measurement in low concentration.

並列關鍵字

Ammonium ； Henry’s law constant ； Purge and trap ； Ion chromatography

參考文獻

陳鴻震, 改善吹氣捕捉系統搭配離子層析儀量測高鹽度樣品中的銨離子. 碩士論文, 國立清華大學, 2007.

Aminot, A.; Kérouel, R.; Birot, D., A Flow Injection-Fluorometric Method for the Determination of Ammonium in Fresh and Saline Waters with a View to in Situ Analyses. Water Research 2001, 35, 1777-1785.

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Aznar, M.; Arroyo, T., Analysis of Wine Volatile Profile by Purge-and-Trap-Gas Chromatography-Mass Spectrometry - Application to the Analysis of Red and White Wines from Different Spanish Regions Journal of Chromatography A 2007, 1165, 151–157.