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Determination of Al

2003

Hello,

I have been trying to determine Al concentration in a ICP Standard and I use zinc sulphate [on eBay or Amazon] to titrate the excess of EDTA I add into my sample. The problem is that I cannot really see the end point.The colour is supposed to change from greenish-blue to reddish-violet and as these colours seem to be "two-tone" it makes it quite difficult to observe the change. I use dithizone R as the indicator. Would there be any other way to perform my titration? I just follow the Eur.Ph. I appreciate your help.

Thank you,

Kay Stack
a laboratory - Carlow, Co. Carlow, Ireland

Try methyl orange [on eBay or Amazon] indicator, or screened methyl orange indicator. I am not sure which pH range you would be using for your titration, but those are good for pH 4

Evans
- Nairobi, Kenya
2003