YSI 9300 Photometer - Manual (Page 127)

PHOTOMETER TEST INSTRUCTIONS
_________________________________________________________________________________________
PHMB
Polyhexamethylbiguanide (PHMB) is an organic biocide used for water
disinfection. PHMB-based sanitisers are widely used for the treatment of
swimming pool water. These sanitisers are typically sold under branded names,
for example Baquacil* (Zeneca), Softswim* (Biolab), Revosil* (Mareva) and
Nicosil* (Nico Norge).
The YSI PHMB test provides a simple means of measuring PHMB-based sanitiser
levels in swimming pool waters over the range 0 - 100 mg/l. The test is
calibrated in terms of commercially available sanitiser products which normally
contain 20% active biocide.
Method
The YSI PHMB test is based on a colorimetric method developed by Palin and now
established as the standard method of testing for polyhexamethylbiguanide. In
the test the PHMB reacts with a sulphone-phthalein indicator under mildly acid
conditions to form an intense blue complex. The indicator itself is yellow in color.
Thus at different PHMB levels a distinctive range of colors from yellow, through
green, to blue are produced.
In the YSI method, the reagents are combined in the form of a single tablet and
the test is simply carried out by adding a tablet to a sample of water. The
intensity of the color produced is proportional to the PHMB concentration and is
measured using a YSI Photometer.
Reagents and Equipment
YSI PHMB-Phot Tablets
YSI 9300 or 9500 Photometer
Round Test Tubes, 10 ml glass (PT 595)
Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
0 – 100 mg/l
PHOT.52.AUTO