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Analysis of orthophosphite

I would like to analyze the content of orthophosphite in an electroless nickel bath after aging. Could anyone please provide or direct me to that information/literature? I have a couple recipes of iodometric titration in hand, but the given famula are different. Therefore, I am looking for the chemistry behind it.

Thank you very much.

Kai Lorcharoensery
Lehigh University - Bethlehem, Pennsylvania, USA
2002

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2002

Kai, try the following procedure:
1. Cool a sample of bath to room temp. Pipette [pipettes on eBay or Amazon [affil links] 1 ml of sample into a 250 ml stoppered iodine flask.
2. Add 50 ml of fresh 50 g/l sodium bicarbonate solution and mix.
3. Pipette 50 ml of 0.05M (0.1N) iodine solution into the flask and leave in a dark place away from strong light for 30 minutes.
4. Add 60 ml of 1:1 acetic acid ⇦this on eBay or Amazon [affil links] and mix.
5. Titrate with 0.1M sodium thiosulphate ⇦this on eBay or Amazon [affil links] to a pale yellow color.
6. Add 5 drops of starch indicator and continue the titration to the purple to colorless end point.
7. Calculation: sodium phosphite g/l =

[(50 x iodine molarity x 2)-(ml thiosulphate x molarity)] x 63
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aliquot (1 ml) Good luck, Alex

Alex Sirota
- Israel

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2006

Mr Kai...to extend the life of electroless nickel bath at this moment the best way is to use electrodialysis with special exchange membranes for regeneration of spent electroless nickel bath. This process is to reduce the orthophosphite back to the hypophosphite.

by the way if you are student from Thailand I would like to be in touch with you . I am working as a chemist/process engineer at the aerospace repair station in LA. Good luck on your research.......
Jiab

Vorakarn Mutsalklisana
- California, USA