毛細管電泳晶片提供快速高量、自動化和微小化，可整合許多分析步驟的潛力，藉由電泳晶片，能夠量測許多疾病的指標物，並且目前已開始應用於臨床研究上。此研究的目的是以ITO電極發展電泳晶片，結合可微小化的電化學感測端，用於亞硝酸根檢測。亞硝酸根在生理上已被認定為重要的離子，許多研究發現，標定亞硝酸根的濃度可具有診斷的應用性，尤其在心血管疾病方面。研究中使用微機電製程，將蝕刻出的ITO電極，在顯微鏡下對準於PDMS管道的出口端，接著電沉積上白金分別做為工作與參考電極，即完成end channel模式的電泳晶片，並可藉著清洗電極以及更換新的PDMS而重複使用。影響亞硝酸根檢測的因素有分離電壓、電滲流力、注入樣本量與檢測電位，結果顯示，(1)每次修飾PDDA(Poly (diallyldimethylammoniumchloride))能讓電滲流力維持在-2~-2.5×10-4 cm2/sV，(2)使用負電壓與表面修飾能夠成功分離亞硝酸根，(3)+0.5 V(vs. Pt)能完全將表面的亞硝酸根反應，(4)以注入電場-300 V/cm注入6秒，能提供足夠的樣本量，(5)在-100 V/cm的分離電場下重複操作7次，亞硝酸根均出現於65秒附近，(6)量測10-100 M的亞硝酸根，線性相關係數為0.992。結果說明此一簡易的晶片能達到檢測10 M亞硝酸根的要求，儘管還需要降低100倍才能符合人體內的濃度範圍。

Microchip capillary electrophoresis has potential to offer high-throughput, automation, miniaturization and integration with many analytical procedures. Microchip has been applied to clinical studies recently. With various designed microchip, we are able to detect biomarkers of diseases. The aim of this study is to develop a microchip capillary electrophoresis using ITO glass with miniaturized electrochemical detection for nitrite sensing. Nitrite has been considered as an important molecular in physiology. It has been shown that monitoring nitrite levels could have great potential for diagnostic purposes, especially in cardiovascular diseases. In this separation and detection system, ITO electrodes fabricated by lithography were aligned to an exist of separation channel (also called end channel mode) under a microscope. Then, ITO electrodes were deposited Pt as working and reference electrodes respectively. This system can be rebuilt easily with a new PDMS and Pt regeneration. Factors influencing the separation and detection, including separation field strength, electroosmotic flow, injection volume and detection potential were studied. Results showed that (1) Coating with PDDA after each use supported a reverse EOF (cathode to anode) which varied from -2 to -3×10-4 cm2/sV. (2) Nitrite was sensitively detected with surface modification under negative field strength. (3) When the detection potential exceeded +0.5V, nitrite was oxidized thoroughly. (4) The injection volume was sufficient under injection field strength -300 V/cm and injection time 6 sec. (5) The migration time was 65 sec under separation field strength -100 V/cm. No significant variation was noticed after 7 runs while the channel was recoated each time. (6) The calibration curve was linear for nitrite over concentration range 10-100 M, with coefficient 0.992. The results demonstrate that ITO microchip with end channel mode can obtain good performance easily although it is necessary to increase the sensitivity by more than a factor of 100 for clinical application.

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