Hach DR2400 Manual page 430

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Within two minutes

after the timer beeps,

wipe the ampule and

place it into the cell

Interferences

Chloride concentrations above 100 mg/L will cause low results. The test may be used at high chloride

concentrations (seawater) but a calibration must be done using standards spiked to the same chloride

concentration.

Interferes at all levels

Compensate for nitrite interference as follows:

a) Add 30-g/L Bromine Water (Cat. No. 2211-20) dropwise to the sample in step 3 until a yellow color remains.

b) Add one drop of 30-g/L Phenol Solution (Cat. No. 2112-20) to destroy the color.

Proceed with step 4. Report the results as total nitrate and nitrite.

Highly buffered samples or extreme sample pH may exceed the buffering capacity of the reagents and require

sample pretreatment.

oxidizing and

Interfere at all levels

Sample Collection, Storage and Preservation

Results will appear in

Interference Levels and Treatments

Most reliable results are obtained when samples are analyzed as soon as possible

after collection. If prompt analysis is impossible, store samples in clean plastic or

glass bottles for up to 24 hours at 4 °C. To preserve samples for longer periods,

add 2 mL of Concentrated Sulfuric Acid (H

store at 4 °C.

) (Cat. No. 979-49) per liter and

Nitrate_AVPP_Mid_CDR_Eng_Ody.fm