46020

Need a nickel nitrate solution analysis faster than EDTA titration  

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Dear all,

We need some information for analysis of Ni % in nickel nitrate solution. Presently we used titration with EDTA solution, but due to lot of sample it takes to much times in a day. We have Ni concentration from 1 % to 25 % in nitrate solution & acid 1% to 15 %. Is density method is OK for this ? we need accurracy for Ni % up to 0.5 %.

Hitesh Patel
Executive - QA - Vadodara, Gujarat, India

I doubt if there is anything faster. Instead, investigate ways to streamline your titration procedure. I would recommend a good fixed volume pipettor, an auto-zeroing burette for the EDTA, a bottletop dispenser (such as Dispensette II) for the ammonia, and something similar for proportioning your murexide. If you do all of that, the titration can easily be done in 45 seconds with practice. That is pretty hard to beat with other methods. The specific gravity approach will not work for nickel in your case because of the varying concentrations of acid in your solution.

Jon Barrows      aerospace jobshop Tulsa, Oklahoma

I have not yet analyzed this element with AAS. But it could be determined faster.

Jose Castellanos
- Minneapolis, MN, USA

You could get yourself a 10 microliter pipette, and a 100 ml volumetric flask. Fill the pipette with the analyte, add 0.1 HCl to the mark, and shake.

Now, transfer 10 ml to a test tube, and add about 25 mg ammonium persulfate; shake till dissolved. Then: 1 ml each 10% sodium citrate solution, 1:1 aqua ammonia, and 1% ethanolic dimethylgloxime solution, shaking well after each addition. Wait a few minutes, and read in a colorimeter at 445 nm. Make a curve with comparably prepared standards, and read your concentration off of it, not neglecting the 10,000 fold dilution factor.

Lots of set up time, but once that is done, perhaps less labor per determination than a titration.

Dave Wichern - The Bronx, New York