Hanna Instruments HI 96750 - Manual (Page 15)

15
INTERFERENCES
The following ions do not interfere below the concentrations reported:
Ammonium
10 ppm
Calcium 10000 ppm as CaCO
3
Chlorine 12000 ppm
Magnesium 8000 ppm as CaCO
3
Sodium 8000 ppm
Color or suspended matter in large amounts will cause interference. Therefore the turbidity
should be removed by prior filtration.
For best results samples should be tested at room temperature (20
OC C or 68 O F). Lower
temperatures will result in higher readings.
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.
Note: The validation is performed only for the selected parameter. For full validation of the
instrument, the following procedure must be performed for each parameter.
• If the analysis result is over the method range, the sample should
be diluted.
• Use the syringe to measure 10mL of sample.
• To measure exactly 10 mL of sample with the 5 mL syringe,
push the plunger completely into the syringe and insert the tip
into the sample. Pull the plunger out until the lower edge of the
seal is on the 5 mL mark of the syringe.
• Remove the cap and fill the Demineralizer Bottle with tap water.
• Replace the cap and shake gently for at least 2 minutes.
• Open the upper part of the Demineralizer Bottle cap and gently
squirt the demineralized water into the cylinder, up to the 100 mL
mark.
Note : The ion exchange resin contained in the Demineralizer Bottle
is provided with an indicator substance. The indicator will
change from green to blue when the resin has been exhausted
and needs to be replaced.
• Pour the solution in the 170 mL beaker, replace the cap and
invert several times to mix. This is the diluted sample.
•
Select P2 program. The readings on diluted sample are performed
similary as for P1 method. The results are converted automatically
by meter.
Note : The conversion factor for dilution is included in software of P2.