在毛細管區域電泳實驗中，通常在高電壓下實驗會產生焦爾熱效應，其主要原因是因為毛細管內溫度控制及熱消散問題。 通常我們利用電壓和(電滲流或電泳動)泳動度作圖，在低壓下是符合歐姆定律，但在高壓下焦爾效應產生，隨著毛細管內部溫度無法有效的消散，造成管內溫度上升，進而使溶液黏度下降。我們經由簡單溫度分析去了解到毛細管內部的熱傳效應，發現電滲流泳動度和電流值呈現線性比例關係，而且可以忽略毛細管內焦爾效應和不均勻的熱對流效應。將這種把溫度效應相消的結果稱作溫度的不敏感性，類似Walden’s 定律可將黏度和電流值比率得到一常數的關係。我們設計一連串的實驗，去證實溫度不敏感性和電動力學性質的行為。最後我們建議要避免焦爾效應於不均勻的溫度控制下，最好是利用電流作為控制的主要參數，而非電壓。 Capillary zone electrophoresis generally suffers the Joule effect at relatively high driven voltage owing to the temperature control problem. In the plot of migration velocity against voltage, the electroosmotic (and electrophoretic) mobility remains a constant at lower voltage but becomes to grow at higher voltage. It is attributed to the reduction of the solvent viscosity caused by the temperature increase. A simple analytical theory is derived to show that the electroosmotic velocity is linearly proportional to the electric current regardless of the temperature profile inside the capillary due to Joule heating and non-uniform surrounding convection. This temperature-insensitive behavior is caused by the cancellation of the temperature effects such as the Walden’s rule for the constant product between solvent viscosity and electric conductivity. A series of experiments has been performed to confirm the temperature-insensitive electrokinetic behavior. Our results suggest that the Joule effect can be circumvented by controlling the electric current even under non-uniform surrounding convection.
