Hanna Instruments HI 96733 - Manual (Page 8)

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• Press ZERO/CFM and the lamp, cuvette
and detector icons will appear on the
display, depending on the measurement
phase.
• After a few seconds, the display will show
“-0.0-” . The meter is now zeroed and
ready for measurement.
• Remove the cuvette, open it and add 4
drops of HI 93733A-0 Nessler Reagent.
Replace the cap and swirl the cuvette
gently to mix.
• Replace the cuvette into the cuvette holder
and ensure that the notch on the cap is
positioned securely into the groove.
• Press and hold READ/ /TIMER for three
seconds. The display will show the
countdown prior to measurement. The
beeper is playing a beep at the end of
countdown period.
Alternatively, wait for 3 minutes and 30
seconds and just press READ/ /TIMER.
In both cases, the lamp, cuvette and
detector icons will appear on the display,
depending on the measurement phase.
• At the end of measurement, the instrument
directly displays concentration in mg/L of
ammonium ion (NH
4
+ ) on the LCD. To convert
the reading to mg/L of ammonia (NH
3
),
multiply by the factor 0.944. To convert the
reading to mg/L of ammonia nitrogen
(NH
3
-N), multiply by the factor 0.776.
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. For accurate validation, please
perform test at room temperature: 18 to 25°C (64.5 to 77.0°F)
• Turn the meter on by pressing ON/OFF.
• When the beeper sounds briefly and the
LCD displays dashes, the meter is ready.
INTERFERENCES
• Organic compounds like: chloramines, various aliphatic and aromatic amines, glycine,
(positive error).
To eliminate these interferences distillation is required.
• Organic compounds like: aldehydes, alcohols (e.g. ethanol) or acetone (negative error).
To eliminate these interferences distillation is required.
• Sulfide (S 2- ): may cause turbidity.
• Hardness above 1 g/L as Calcium Carbonate (CaCO
3
).
• Place the cuvette into the cuvette holder
and ensure that the notch on the cap is
positioned securely into the groove.