滴定分析中固、液体鉻黑T指示剂应用比较

Application Comparison of Solid EBT and Liquid EBT Indicators in Titration Analysis

分别采用初配和配制7天后的固、液体鉻黑T指示剂标定EDTA溶液及测定水的总硬度,根据实验结果分析两种形态指示剂的使用效果,结果表明,新配制的EBT固、液指示剂,标定EDTA时有显著性差异,测定水的总硬度时,两种指示剂无显著性差异;配制7天后的EBT固、液指示剂,标定EDTA及测定水的总硬度时,使用两种指示剂均存在显著性差异.经F检验,液体鉻黑T指示剂放置7天后测定精密度低于新配制指示剂,固体鉻黑T指示剂放置前后测定精密度无显著变化.因此得出结论,若实验时新配制指示剂,选用液态为佳,否则,要使用固体鉻黑T指示剂.

Solid and liquid EBT indicators compounded newly or 7 days before were used to determine the concentration of EDTA and the total hardness of water,according to the results,the effect of two types of indicators was found,it was that there are significant differences in calibrating EDTA when using the solid and liquid EBT compounded newly,but there are no significant differences in determining the total hardness of water by using that.When using the two types of EBT compounded 7 days before,there are both significant differences in calibrating EDTA and determining the hardness of water.The precision of determination by using liquid EBT compounded 7 days before is lower than that by using liquid EBT compounded newly,but there is no significant difference between the two solid EBT indicators.So,it was concluded that when using EBT compounded newly,the liquid type was the best,otherwise we should choose the solid type.