以多通道偵測器觀察流動訊號在毛細管柱之時間效應

Abstract

對於流動型分析儀器的訊號，最近有文獻中提出時間效應的假說。所謂時間效應是指樣品在管路中流動時，由於樣品在管內的空間分佈狀態隨時間一直在改變，而傳統單通道偵測器收集到的訊號其實是樣品在管內不斷變化累積的結果，使得測量結果與樣品在管路內的空間分佈並不相同。 本研究之目的在於討論毛細管內流動訊號，是否有時間效應的存在，更進一步探討樣品推動力以及管柱內徑的大小，是否影響著時間效應的表現程度。 我們發展了一套多通道偵測系統，它能在流動注入分析系統中，獲得樣品在管路內的空間分佈狀態(空圖)，及記錄隨流析時間得到的訊號圖形(時圖)，對實驗所得波形各指標參數，包含不對稱因子、分散係數等進行比較，以及進行「空時疊圖」的波形比較，發現在內徑較大的毛細管確實存在著「時間效應」，而隨著管柱內徑的增大，此效應也愈趨明顯，證明傳統偵測器所得的波形呈現拖尾的原因，有部份原因是由「時間效應」造成的，且毛細管內徑之大小是影響此效應的重要因素。

Signals of flowing type analytical instruments are subjected to a hypothesis of temporal effect that was proposed recently. This study tries to examine whether the temporal effect exists in flowing signals of capillary tubing. Furthermore, we discuss if this effect changes in different inside diameter tubing. The temporal effect occurs while sample molecules are passing a fix-position detector. Because the spatial distribution of the sample in the flow tube changes with time, the recorded signal from a traditional single-channel detector is actually the accumulation result of the constant signal variation of the sample in the tube. Accordingly, the recorded signal as a function of time is different from the true spatial distribution of the sample in the flow tube. We developed a multi-channel detection system that is able to scrutinize the spatial distribution of the sample and the peak shape recorded as a function of time simultaneously in flowing systems. By comparing peak shapes between spatial and temporal profiles, we explored that the temporal effect exists in tubes of large inner diameters. This effect increases as the inner diameter becomes larger. This study confirms that the temporal effect is one of the factors responsible for the skewed flowing peaks. Additionally, inner diameter of the tube is an important factor affecting this effect.