Velp Scientifica
– UDK139 Operating Manual
10004762/B5
114
39 -
Determination of phenols in drinking water and in industrial
wastes
The determination of phenols is one of the routine analysis in order to assess the
quality in drinking and ground water and in domestic and industrial wastes.
Procedure
1) Sample:
If the sample to be analyzed contains oxidizing agents (e.g. chlorine), oils and tars or
sulphur compounds, it must be treated at sampling or before distillation according to
the official method prescription.
2) Reagents and equipment:
Phosphoric acid (H3PO4) diluted (1 : 10). 100 ml of phosphoric acid
concentrated (85%, d 1,68) mixed with 900 ml of distilled water.
Copper sulphate (CuSO4
5 H2O) solution 10%. 100 g of salt dissolved in
distilled water for a final volume of 1000 ml.
Distilled water, previously boiled and cooled (Type II)
Aminoantipyrine solution: dissolve 2 g of 4-aminoantipyrine in 100 ml of distilled
water
Potassium ferricyanide solution: dissolve 8 g of K
3
Fe(CN)
6
in 100 ml of distilled
water
Ammonium chloride solution 2%: dissolve 20 g of NH
4
Cl in 1000 ml of distilled
water
Ammonia 25 %
Concentrated phenol solution (1000 mg/l): dissolve 250 mg of phenol in 250 ml
of freshly boiled and cooled distilled water
Diluted phenol solution (10 mg/l): dilute 2.5 ml of the concentrated phenol
solution to 250 ml
Chloroform, analytical grade
Photometer for use at 460 nm
50 mm glass cuvette
pH meter
500 ml volumetric flasks
500 or 1000 ml separatory funnels
Filter papers
3) Sample preparation:
before distillation the water sample is to be acidified to pH 4 by phosphoric acid. Add
1 ml of solution 10% of copper sulphate to 100 ml of sample and introduce in the test
tube.
4) Distillation:
Set the following analytical parameters:
Addition of reagents:
H2O=0
H3BO3=0
NaOH=0
Distillation time: 8 min
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