变色酸分光光度法测定镍基纳米复合镀层中TiO_2共析量

Spectrophotometric determination of total precipitated quantities of titanium dioxide in Ni-based nano-composite coatings

建立了分光光度测定镍基纳米复合镀层中TiO2共析量的方法。在甲酸-甲酸钠缓冲溶液介质中,Ti(Ⅳ)与变色酸瞬间反应生成紫红色络合物,络合物的最大吸收波长为480 nm,钛在0-7.0μg/mL范围内遵守比尔定律,表观摩尔吸光系数为1.44×104L.mol-1.cm-1,100倍量的镍对测定没有干扰,在掩蔽剂抗坏血酸存在下可允许8 mg Fe3+和3 mg Cu2+存在。方法已用于镍基纳米复合镀层中TiO2共析量的测定,相对标准偏差为1.8%-3.9%,回收率在96.7%-104.3%之间。

A spectrophotometric method for the determination of total precipitated quantities in Ni-based nano-composite coatings was developed. In formic acid- sodium formate buffer medium,Ti（iV） reacts with chromotropic acid to form a violet-red complex. The maximum absorption of the complex is at 480 nm. Beer＇s law is obeyed in the range of 0 - 7.0μg/mL for titanium. The apparent molar absorptivity of 1.44×10^4L·mol^-1·cm^-1 is gained. A hundred fold amount of nickel relative to titanium do not interfere in the determination. In the presence of ascorbic acid as masking reagent, 8 mg Fe^3＋ and 3 mg Cu^2＋ do not also interfere. The method is simple and accurate. It is used to determine total precipitated quantities in Ni-based nano-composite coatings with RSDs of 1.8 % - 3.9 % and recoveries of 96.7 % - 104.3 %.