本研究利用脂肪醇化合物作為氣相分佈追蹤劑，來量測不飽合層土壤中的含水率，實驗設計是利用管柱實驗來模擬真實土壤層。為了尋找最佳的脂肪醇化合物，本研究首先利用各種不同之醇類(甲、乙、丙、丁、戊、己醇等)進行試驗。氣相追蹤劑在經過土壤管柱後，將經由GC/FID儀器偵測得到實驗穿透曲線，此數據在帶入擬合程式之後，可經由最佳化計算來得到遲滯係數。利用遲滯係數與水飽和度關係，吾人可推估出土壤含水率。本研究發現，在各種不同之純類化合物中，以戊醇之表現最佳。在利用戊醇為氣相追蹤劑以量測不同特性土壤含水率之實驗中發現，當土壤粒徑小於或等於0.31 mm時，若此時之水飽和度小於0.15，則此法可以非常有效的量測含水率；而當粒徑大於0.31 mm時，其精確度開始降低，原因是因為質傳現象造成模式擬合不準確以及實驗過程中含水率本身產生變化所致。 Aliphatic alcohols were employed as gas-phase partitioning tracer to determine moisture content in unsaturated soils. Laboratory column experiments were conducted to mimic field conditions. A series of alcohols, including methanol, ethanol, proponal, butanol, pentanol, and hexanol, were screened. Alcohol vapors exiting the column were detected by GC/FID, and the breakthrough curves were obtained. The STANMOD program was applied to obtain the retardation factor factor from the breakthrough curves. With the retardation factor, the degree of water saturation was then calculated. It was found that pentanol was the best tracer for this purpose. Pentanol vapor was then used as tracer to determine water content in sands with various characteristics. It was found that this method can effectively determine water content in soils when the particle diameter is less than 0.31 mm and the water saturation is less than 0.15. When the particle size is larger than 0.31 mm, its efficiency decreases. This is mainly due to mass transfer limitations and water movement.
