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3
Photometer 7500
Nitrate
Range:
Colour change: Colourless - Red
1 Take a clean Nitratest Tube (PT 526). Using the
Measuring Syringe (PT 361) add 1ml of sample.
Fill the Nitratest Tube to the 20ml mark with
deionised water.
2 Add one level spoonful of Nitratest Powder and
one Nitratest tablet. Do not crush the tablet.
Replace screw cap and shake tube well for exactly
one minute then allow contents to settle.
3 Then, either: Invert tube gently 2 or 3 times and
then allow to stand for at least two minutes to
ensure complete settlement. Remove screw cap and
wipe around top with a clean tissue. Decant clear
solution into test cuvette, filling to the 10ml mark.
or: Using the Palintest Filtration Set (PT 600) filter
a portion of the solution through a GF/B filter
paper into a test cuvette filling to the 10ml mark.
4 Add one Nitricol tablet, crush and mix to dissolve.
5 Stand for 10 minutes.
6 Take photometer reading.
Nitrite
Range:
Colour change: Colourless - Red
1 Fill test cuvette with sample to the 10ml mark.
2 Add one Nitricol tablet, crush and mix to dissolve.
3 Stand for 10 minutes.
4 Take photometer reading.
Ammonia
Range:
Colour change: Yellow - Green
1 Fill test cuvette with sample to the 10ml mark.
2 Add one Ammonia No 1 tablet and one
Ammonia No 2 tablet, crush and mix to dissolve.
3 Stand for 10 minutes.
4 Take photometer reading.
22
22
0-20mg/l (ppm) N
0-0.5mg/l (ppm) N
0-1.00mg/l (ppm) N
3.7 Calibration/Validation
Your Photometer 7500 is delivered with a
calibration certificate validating the performance of
the instrument as it leaves Palintest.
We recommend annual service and calibration
of all photometric instruments in normal use.
The Photometer 7500 also includes an automatic
routine to validate analytical performance using
certified Palintest Check Standards. Accessed via the
Mode menu, the Check Standard Mode provides
a field method of ensuring your instrument is
operating within defined specifications and also a
troubleshooting method for unexpected results.
Every Palintest Check Standards set is supplied with
certified values expressed as %T (Transmission), derived
from traceable reference materials. Acceptable tolerances
are defined on the certificate and are automatically
specified within the Photometer 7500.
Check Standard Mode
Access Check Standard Mode from the Mode screen.
Highlight Check Standard Mode and press OK.
Two choices are offered:
Enter Check
use the up/down keys to
Standard Values
adjust the displayed values
to match the certificate
Check Standard
insert the Check Standards
Measurement
in the defined order to
generate a validation report
Enter Check Standard Values
Each standard has two values assigned, for two
individual wavelengths.
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