45-35
PHENOLS, continued
19. Press: READ
The display will
count down to 0.
Then the display will
show the results in
mg/L phenols.
SAMPLING AND STORAGE
Most reliable results are obtained when samples are analyzed within
four hours after collection. The following storage instructions are
necessary only when prompt analysis is impossible. Collect 500 mL of
sample in clean glass containers and add the contents of two Copper
Sulfate Powder Pillows. Adjust the sample pH to 4 or below with 10%
Phosphoric Acid Solution. Store at 4 °C (39 °F) or lower and analyze
within 24 hours.
ACCURACY CHECK
Standard Solution Method
Verify accuracy of the test by performing the analysis procedure using
known phenol standard solutions in place of the test sample. For
greatest accuracy, standard solutions should be analyzed periodically to
verify test accuracy and when new reagent lots are first used. Prepare
standards as follows:
a) Weigh out 1.00 g of phenol, ACS. Transfer to a 1-liter volumetric
flask. Dilute to the mark with freshly boiled and cooled demineralized
water. This is a 1-g/L stock solution.
b) Transfer 1 mL of the 1-g/L stock solution to a 100-mL volumetric
flask. Dilute to the mark with demineralized water. This is a 10-mg/L
working solution.
c) Prepare 0.06, 0.12 and 0.18 mg/L standard solutions by using a pipet
to add 3, 6 and 9 mL of the 10-mg/L working solution, respectively, to
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