YSI 9300 Photometer - Manual (Page 93)

PHOTOMETER TEST INSTRUCTIONS
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Potassium is an abundant natural element. However in fresh water potassium
levels are normally low. Higher levels can be observed in brackish waters. The
guide level prescribed for drinking water supplies under the EEC Regulations is
10 mg/l.
The YSI Potassium test provides a simple means of testing potassium levels in
water over the range 0 - 12.0 mg/l.
Method
The YSI Potassium test is based on a single tablet reagent containing sodium
tetraphenylboron. Potassium salts react with sodium tetraphenyl-boron to form
an insoluble white complex. At the potassium levels encountered in the test, this
is observed as a turbidity in the test sample. The degree of turbidity is
proportional to the potassium concentration and is measured using a YSI
Photometer.
Reagents and Equipment
YSI Potassium K Tablets
YSI 9300 or 9500 Photometer
Round Test Tubes, 10 ml glass (PT 595)
Test Procedure
1 Fill test tube with sample to the 10 ml mark.
2 Add one Potassium K tablet, crush and mix to dissolve. A cloudy solution
indicates the presence of potassium.
3 Select Phot 30 on photometer.
4 Take photometer reading in usual manner (see photometer instructions).
5 The result is displayed as mg/l K.
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Photometer Method
AUTOMATIC
WAVELENGTH
SELECTION
0 – 12.0 mg/l
PHOT.30.AUTO