Assay for Glutaraldehyde and Formaldehyde
The method involves a titration against a blank followed by the titration against the unknown sample. The method is based formation of an aldehyde-bisulphite complex followed by iodometric titration of the unreacted bisulphite. Accuracy is about 0.2% (FRIGERIO and SHAW, 1969).
- 0.125 M Na2S2O5
- 2.37 g Na2S2O5 to 100ml with distilled water
- 0.1 M potassium tri-iodide
- 11.00 g KI + 6.44 g resublimed I2 to 250ml with distilled water
Perform two titrations with 0.1 M I3- judging the end point as follows:
The solution turns yellow at first but within 0.2 ml of the endpoint becomes colourless - continue titrating until the solution again turns yellow and remains yellow for three minutes.
Titration 1 to give V1
1 ml aldehyde solution (0.6% to 6%) 20 ml 0.125M Na2S2O5
Titration 2 to give V2
1 ml water 20 ml 0.125M Na2S2O5
FRIGERIO, N. A., and M. J. SHAW. 1969. A SIMPLE METHOD FOR DETERMINATION OF GLUTARALDEHYDE. Journal of Histochemistry & Cytochemistry. SAGE Publications, March 1. http://dx.doi.org/10.1177/17.3.176.