Hanna Instruments HI 83206-2008 User Manual

Page 14

Chromium VI HR

CHROMIUM VI HIGH RANGE

SPECIFICATIONS

Range

0 to 1000 µg/L

Resolution

1 µg/L

Accuracy

±5 µg/L ±4% of reading

Typical EMC

±1 µg/L

Deviation

Light Source

Tungsten lamp with narrow band interference filter @ 525 nm

Method

Adaptation of the

ASTM Manual of Water and Environmental Technology, D1687-92,

Diphenylcarbohydrazide method. The reaction between chromium VI and the reagent

causes a purple tint in the sample.

REQUIRED REAGENTS

Code

Description

Quantity

HI 93723-0

Powder reagent

1 packet

REAGENT SETS

HI 93723-01 Reagents for 100 tests
HI 93723-03 Reagents for 300 tests

For other accessories see page 73.

MEASUREMENT PROCEDURE

• Select the

Chromium VI HR method using the procedure described in

the

Method Selection section (see page 12).

• Fill the cuvette up to the mark with 10 mL of unreacted sample and replace

the cap.

• Place the cuvette into the holder and close the lid.

• Press ZERO key. The meter will show “-0.0-” when the meter is zeroed

and ready for measurement.

• Remove the cuvette and add the content of one packet of

HI 93723-0 reagent. Replace the cap and shake vigorously
for about 10 seconds.

10 mL

• Press TIMER and the display will show the countdown prior to the measurement or, alternatively, wait

for 2 minutes and 30 seconds and press READ. When the timer ends the meter will perform the reading.

• The instrument displays the results in mg/L of total chlorine.

Note: free and total chlorine have to be measured separately with fresh unreacted samples following the

related procedure if both values are requested.

INTERFERENCES

Interference may be caused by: Bromine, Iodine, Ozone, Oxidized forms of Chromium and Manganese.
In case of water with hardness greater than 500 mg/L CaCO

, shake the sample for approximately 2

minutes after adding the powder reagent.
In case of water with alkalinity greater than 250 mg/L CaCO

or acidity greater than 150 mg/L CaCO

the color of the sample may develop only partially, or may rapidly fade. To resolve this, neutralize the

sample with diluted HCl or NaOH.

Total Chlorine