本研究的主要目的是利用微波電漿氣相化學沉積法之技術自製導電鑽石薄膜電極，探討導電鑽石薄膜電極製程參數對電化學行為的影響，並且用電化學方法將奈米白金顆粒修飾導上電鑽石薄膜電極來偵測環境毒物-砷(III)。由於導電鑽石薄膜電極在電分析化學上比傳統電極有更多的優點包括耐久性、電導性、優良的化學惰性、較低的背景電流、較廣的偵測電位、抗熱、抗酸...等特性。所以發展導電鑽石薄膜電極來當做工作電極。 導電鑽石薄膜電極製備在1500W微波功率、55torr氣體總壓、氫氣流速300sccm、甲烷流速50sccm、B(OCH3)3流速5sccm下，並施加-125V直流偏壓成核20分鐘、成長180分鐘即完成電極製備，此導電鑽石薄膜電極對1mM K3Fe(CN)6在循環伏安法的反應其標準偏差值為3.13% (n=8)。 電化學實驗選擇奈米白金修飾導電鑽石電極以計時安培法(Chronoamperomtric)進行環境毒物-砷(III)的偵測，利用循環伏安法在1.2～-0.2V電位區間以50 mV/sec的掃描條件下連續掃描20分鐘以修飾上奈米白金顆粒，偵測環境為0.1M pH4 醋酸緩衝溶液，偵測電位為0.8V (vs. Ag/AgCl)，前處理電位0.2V (vs. Ag/AgCl)，前處理時間15秒，偵測取樣時間為5秒。線性範圍0.1～100 (R=0.998)，靈敏度為273.25μA/mM，本系統的偵測極限(S/N=3)為16.7 nM，重複操作的相對標準偏差為1.013%(n=20)。 Conductive boron-doped diamond (BDD) electrode has attracted intensive attention recently. This prominent new material possess characteristics like its high electronic conductivity, excellent chemical inertness, a wide potential window, small residual current, as well as physical and chemical stability. This home-made BDD electrode, prepared by utilizing microwave plasma enhanced chemical vapor deposition (MPECVD) making electrode, is widely used for the detection environmental and biological samples. A new scheme to measure Arsenic(III) with platinum nanoparticle modified boron doped diamond electrode was proposed by using chronoamperometry at the optimum conditions at buffer solution : 0.1M, pH4 acetate buffer; initial potential: 200mV(vs. Ag/AgCl) applied 20 seconds；detection potential: 800 mV(vs. Ag/AgCl); sampling time: 5sec. The sampling time in chronoamperometry was sampling at the 5th second after the potential step. According to optimum operation conditions, the linear range of Arsenic(III) is obtained between 10 to 100 μM (R=0.998), and its sensitivity is 273.25 μA/mM with estimated detection limited about 16.7 nM (S/N=3). The relative standard deviation of twenty repetitive detections is 1.013%.
