超声溶解-电位滴定法测定硅钢涂层用纳米二氧化钛中氯

Determination of chlorine in nanoscale titanium dioxide used in silicon steel coating by potentiometric titration with ultrasonic dissolution

采用加酸后超声震荡的方法处理样品,建立了电位滴定法测定了硅钢涂层用纳米二氧化钛中氯离子含量的方法。实验确定了最佳条件：称取0.1g过300目（50μm）筛孔的样品,加入20mL硝酸（1＋5）后,在90kHz的条件下室温超声振荡30min,过滤后稀释,以等体积自动加入0.10mL 0.01mol/L硝酸银标准滴定溶液的方式进行滴定,以d2 E/dV2-V滴定曲线中E/V的二阶倒数为零时计算滴定终点。将方法应用于硅钢涂层用纳米二氧化钛实际样品分析,结果与分光光度法一致,相对标准偏差（RSD,n=8）小于5%,加标回收率为99%-102%。

The sample was treated in acid by ultrasonic oscillation.A determination method of chlorine ion content in nanoscale titanium dioxide used in silicon steel coating was established by potentiometric titration.The optimal conditions were obtained by experiments：0.1g of sample was screened with 300-mesh（50μm）sieve;the sample was dissolved at room temperature with 20 mL of nitric acid（1＋5）by ultrasonic oscillation at 90 kHz for 30min;after filtration and dilution,the sample solution was titrated with0.10 mL of 0.01mol/L silver nitrate standard titration solution by isovolumetric automatic addition.The titration endpoint was calculated when the second derivative of E/Vin d2 E/dV2-V titration curve was zero.The proposed method was applied to the analysis of actual sample of nanoscale titanium dioxide used in silicon steel coating.The results were consistent with those obtained by spectrophotometry.The relative standard deviation（RSD,n=8）was less than 5%,and the recoveries were between 99% and 102%.