YSI 9300 Photometer - Manual (Page 132)

Reagents and Equipment
YSI Phenoltest No 1 Tablets
YSI Phenoltest No 2 Tablets
YSI Phenoltest PR Tablets
YSI 9300 or 9500 Photometer
Round Test Tubes, 10 ml glass (PT 595)
Test Procedure
1 Fill round test tube to the 10 ml mark with sample.
2 In the case of samples known to contain copper, zinc, iron or manganese
ions, add one Phenoltest PR tablet. Crush and mix to dissolve.
3 Add one Phenoltest No 1 tablet, crush and mix to dissolve.
4 Add one Phenoltest No 2 tablet, crush and mix to dissolve.
5 Stand for 10 minutes to allow full color development.
6 Select Phot 54 on the photometer.
7 Take photometer reading in the usual manner (see photometer instructions).
8 The result is displayed as mg/l C
6
H
5
OH.
Interferences
1 Use of the Phenoltest PR tablet will prevent interference from metal ions up
to a concentration of 350 mg/l. The test is unaffected by free chlorine in the
sample up to 10 mg/l.
2 Low results may be obtained in samples containing more than 150 mg/l
alkalinity (as CaCO
3
), 10 mg/l sulphite or 2 mg/l sulphide. Certain organic
keto-enol compounds may cause high results. In the case of known or
suspected interferences, then the sample should be pre-treated in accordance
with standard analytical procedures.
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