15
Calcium (Ca
2+
):
above 10,000 mg/L as CaCO
3
Copper (Cu
2+
):
does not interfere: reagent contains a masking
agent.
Magnesium (Mg
2+
):
above 100,000 mg/L as CaCO
3
Molybdate Molybdenum:
above 25 mg/L (as Mo-MoO
4
) (positive error)
Sample containing up to 50 mg/L Mo-MoO
4
may
be measured if a reading is taken after 1 minute
instead of 3 minutes.
High Iron concentrations:
up to 200 mg/L do not inhibit color development;
above 200 mg/L color development may be inhibited.
High sulfide concentrations (S
2-
):
high sulfide concentrations may interfere
To reduce sulfide: acidify the sample and boil for
about 20 minutes, neutralize and adjust volume
before measurements.
Silica (SiO
2
):
above 175 mg/L (as SiO
2
). May slow down color
development (negative error)
VALIDATION PROCEDURE
Use the validation procedure to ensure that the instrument is properly calibrated.
Warning:
Do not validate the instrument with any standard solutions other than the HANNA
CAL
CHECK
TM
Standards, otherwise erroneous results will be obtained.
•
Turn the meter on by pressing
ON/OFF
.
• Place the
CAL CHECK
TM
Standard
HI 96721-11
Cuvette A into the cuvette
holder and ensure that the notch on the
cap is positioned securely into the groove.
• When the beeper sounds briefly and the
LCD displays dashes, the meter is ready.