MONITOR
PROCESS PHOTOMETRY
No. 06000-1R/A
ACIDITY: Thymol Blue method
Range: 0 - 500 mg/l CaCO3
PRINCIPLE
The automated procedure for acidity is an adaptation of the technique outlined in “Standard Methods”. Thymol blu indicator is used in place of phenolphthalein. In this procedure, the color transition range of the indicator is extended by use of a buffer, the PH of which is near the initial transition point. In this way slight changes in acidity will result in only gradual change in indicator color, instead of the usual sharp change of the acid-base titration.
The colorimetric procedure is of inverse type.
The color change is measured at 600 nm
