Hanna Instruments HI 83205-2008 - Manual (Page 18)

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• Reinsert the cuvette into the instrument.
• Press TIMER and the display will show the countdown prior to the
measurement or, alternatively, wait for 6 minutes and press READ.
When the timer ends the meter will perform the reading. The
instrument displays concentration in µg/L of chromium VI.
• Press the or to access the second level of functions.
• Press the Chem Frm functional key to convert the result in µg/L of Chromate (CrO
4
2- ) and Dichromate
(Cr
2
O
7
2- ).
• Press the or to go back to the measurement screen.
INTERFERENCES
Interference may be caused by:
Vanadium above 1 ppm. However, waiting 10 minutes before reading, the interference is removed
Iron above 1 ppm
Mercurous and mercuric ions cause slight inhibition of the reaction.
Chromium VI HR 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 de-
scribed 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