分光光度法测定食品中铁的含量

研究了显色剂4-(2-噻唑偶氮)间苯二酚(简称TAR)与铁(Ⅱ)的显色反应.实验表明,在pH=10.0的NH3-NH4Cl缓冲介质中,铁(Ⅱ)与TAR形成红色的络合物,其最大吸收波长位于733nm处,表观摩尔吸光系数为6.98×104L·mol-1·cm-1,铁(Ⅱ)含量在0-25μg/25mL范围内符合比耳定律.方法用于食品中微量铁的测定,结果令人满意.     

氢气泡模板电沉积多孔金属镍薄膜

Porous nickel films have been successfully electrodeposited using cathodic hydrogen bubbles as a template. The influence of deposition parameters including concentration, temperature and current density on the films morphologies has been systematically studied. SEM results showed that increase in current density resulted in the deposits with higher pore density and smaller pore size. Both the pore size and thickness of the pore walls increased with the electrolyte temperature range from 20 to 60 ℃ when the other deposition parameters were fixed. Increasing the concentration of NiCl₂ or NH₄Cl in the electrolyte led to the thicker of the pore walls and declined pore size and density. The deposits displayed a dendritic morphology in cross-sectional SEM image. Electrochemical characterization of the porous nickel films after surface oxidation in 1.0 mol·L^-1 NaOH solution showed that specific capacitance as high as 7.2 F·g^-1 could be reached.