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911.
912.
Upon the electrochemical oxidation of tris(2,2′-bipyridyl) ruthenium(II) [Ru(bpy)2+3] and hydroxyl carboxylic acids, for instance, citric acid, tartaric acid, malic acid, and
-gluconic acid, bright electrochemiluminescences (ECLs) were observed. Different luminescent reactions were presented depending on the applied potential. The light emission was mainly caused by the reaction between alkoxide radical ion and Ru(bpy)3+3below the potential +1.80 V (vs Ag/AgCl). The luminescence intensity obviously increased because of the more complex reaction process. The luminescence wavelength of 608 nm, which could be found either at higher potential than +1.80 V or in the potential range from +1.30 to +1.80 V, confirmed that ECL was caused by Ru(bpy)2+3*. The factors which affect the determination and HPLC separation of the four acids were also investigated. 相似文献
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CVD法不同条件下制备的多壁碳纳米管的Fenton氧化改性 总被引:2,自引:0,他引:2
碳纳米管经焙烧和稀硝酸纯化处理后,在相同的实验条件下,采用Fenton试剂产生的·OH分别对CVD法合成的两种制备条件不同的多壁碳纳米管进行氧化改性处理。红外光谱(FT IR)表明,改性后的两种碳管结构中都引入了羟基、羰基和羧基等含氧官能团。此外,由于制备条件不同,导致它们的石墨化程度、缺陷含量和抗氧化能力等性质也不同,因此CVD法制备条件能够对碳管Fenton氧化改性结果产生重要影响。机理分析表明,这些含氧官能团可以看作是具有强亲电性和强氧化性的·OH对碳管上缺陷位置和不饱和键进行攻击的结果。 相似文献
920.
Fang-Hui?Wu Guang-Chao?ZhaoEmail author Xian-Wen?Wei Zhou-Sheng?Yang 《Mikrochimica acta》2004,144(4):243-247
Acid-treated multi-walled carbon nanotubes (MWNTs) were immobilized on the surface of a glassy carbon electrode to form an MWNT-modified electrode. The electrocatalytic response of the modified electrode towards tryptophan (Trp) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results demonstrated that the modified electrode exhibited a high degree of catalytic activity towards the oxidation of Trp. An oxidation peak was obtained in Trp solution at the MWNT-modified electrode. Compared with a bare electrode, the peak current had obviously increased, and the peak potential had shifted in a negative direction. However, under the same conditions, no response was observed for other amino acids. The oxidation peak currents were proportional linearly to the concentration of Trp, a property which could be utilized to detect Trp. The determination conditions, such as the concentration, the composition and the pH values of the supporting electrolyte, accumulation time, as well as scan rate etc. were optimized. Under the chosen conditions, the DPV peak current is linear to the concentration of Trp in the range of 2.5×10–7 to 1.0×10–4molL–1, and the detection limit is 2.7×10–8molL–1. Moreover, the detection is free of interference from other amino acids. The modified electrode has been successfully applied to determine the concentration of Trp in composite amino acid injections, and it displays excellent repeatability and higher sensitivity. 相似文献