排序方式: 共有29条查询结果,搜索用时 15 毫秒
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镓(Ⅲ)-茜素氨羧络合剂在碳糊电极上的阳极吸附伏安法研究及应用 总被引:1,自引:0,他引:1
研究了镓(Ⅲ)-茜素氨羧络合剂(ALC)在碳糊电极上的阳极吸附伏安行为,并以此建立了一种高灵敏度、高选择性测定镓的吸附伏安法.在0.12 mol/L HAc-NaAc-0.24 mol/L邻苯二甲酸氢钾底液(pH 4.5)中,-0.10 V (vs.SCE) 富集90 s (或180 s),以250 mV/s扫速线性扫描至0.90 V, Ga3+-ALC在碳糊电极上产生灵敏的与ALC的峰电位相差近230 mV的吸附氧化峰,其二次导数峰电流与镓浓度在5.0×10-10~8.0×10-7 mol/L范围内呈线性关系;富集240 s检出限达3.0×10-10 mol/L(S/N=3).探讨了电极反应机理.该法用于粮食样品中镓的测定,结果满意. 相似文献
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槲皮素化学修饰碳糊电极吸附溶出伏安法测定痕量铅 总被引:14,自引:0,他引:14
建立了用槲皮素修饰碳糊电极测定痕量铅的新方法 ,在 0 .1 0mol L甲酸盐缓冲液 (pH 4.3 )中 ,于 -0 .1 0V(vs.SCE)搅拌富集 ,再在 -0 .70V静止还原 40s后 ,阳极化扫描 ,于 -0 .42V左右获得一灵敏的铅阳极溶出峰。在最佳条件下 ,富集不同时间 ,其二次导数峰电流与Pb2 + 在 1 .0× 1 0 - 8~ 8.0× 1 0 - 7mol L和 2 .0× 1 0 - 9~ 6.0× 1 0 - 8mol L两个范围内呈线性关系 ,检出限为 8.0× 1 0 - 1 0 mol L(S N =3 )。同时初步探讨了电极反应机理。 相似文献
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Man Yan Ren Junan Li Bingru Jin Xinxin Pan Ligang 《Analytical and bioanalytical chemistry》2018,410(28):7511-7521
Analytical and Bioanalytical Chemistry - Alternariol monomethyl ether (AME) is one of the major Alternaria mycotoxins present in a wide range of fruits, vegetables, grains, and their products, and... 相似文献
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A novel procedure was developed for the determination of trace cerium on the basis of anodic adsorption voltammetry of the
Ce(III)–alizarin complexon (ALC) complex at a carbon paste electrode (CPE). The procedure is convenient to determine cerium
individually in the presence of other rare earths because there is a 100 mV difference between the peak potentials of Ce(III)–ALC
and other rare earth(III)–ALC complexes in a supporting electrolyte of 0.08 M HAc–NaAc and 0.012 M potassium biphthalate (pH
4.7) when performing linear-scanning from −0.2 to 0.8 V (vs. SCE) at 100 mV/s. The second-order derivative peak currents are directly proportional to the Ce(III) concentration over
a range of 6.0 × 10−9–3.0 × 10−7 M. The detection limit is as low as 2.0 × 10−9 M (S/N = 3) for a 120 s preconcentration. An RSD of 3.5% was obtained for 15 determinations of Ce(III) at a concentration of 4.0
× 10−8 M on the same CPE surface. The method was applied successfully to the determination of cerium in samples of rare earth nodular
graphite cast iron. 相似文献
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本文构造了一种带权的六点格式,讨论了它的稳定性条件,证明了这种格式的解对微分方程的真解具有单侧逼近的性质;当适当选取权数θ=θ0时,这种格式是一种四阶耗散格式,不仅数值耗散很小,而且满足稳定性条件,不出现非物理振荡;还证明了C.J.Chen的有限分析格式[1]在一定条件下是这种带权格式的一个特殊情形,因此也具有单侧逼近性质;最后给出了几个算例说明上述性质。 相似文献
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A new method for the determination of trace copper was described. A multiwalled carbon nanotube modified carbon paste electrode was prepared and the adsorptive voltammetric behavior of copper‐alizarin red S (ARS) complex at the modified electrode was investigated. By use of the second‐order derivative linear sweep voltammetry, it was found that in 0.04 mol/L acetate buffer solution (pH 4.2) containing 4×10?6 mol/L ARS, when accumulation potential is 0 mV, accumulation time is 60 s and scan rate is 100 mV/s, the complex can be adsorbed on the surface of the electrode, yielding one sensitive reduction peak at ?172 mV (vs. SCE). The peak current of the complex is proportional to the concentration of Cu(II) in the range of 2.0×10?11–4.0×10?7 mol L?1 with a detection limit (S/N=3) of 8.0×10?12 mol/L (4 min accumulation). The proposed method was successfully applied to the determination of copper in biological samples with satisfactory results, the recoveries were found to be 96%–102%. 相似文献