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Photometer 7500 BT
of incident light compared to the light intensity
reaching the detector array. The light intensity is
determined as Transmittance (%T) or Absorbance (A)
and compared to calibration tables stored within the
Photometer 7500 Bluetooth. The stored calibration
tables convert %T or A to results in a variety of
units (mg/l, ppm etc.) as defined in Section 3.4.
Calibration tables are defined by Palintest based
on the measurement of reference standards using
Palintest reagents. To achieve the best quality
results there are a small number of care points:
1
Always use the provided light cap to prevent
ambient light affecting the results.
2
Ensure Sample and Blank cuvettes are clean, dry
and inserted correctly into the sample chamber,
using the allocated orientation mark to align.
3
Always blank the instrument with untreated
sample prior to analysis.
Additional guidance is provided in
Section 3.8
Photometric Testing Hints and Tips
Selecting Test Parameters
The Photometer 7500 Bluetooth offers a number
of choices to select the parameter to test:
Phot Number Entry
- use the numeric keypad
to enter the unique Phot Number to directly
access any programmed calibration (including
User Defined Tests). This method will not be
available if the Photometer 7500 Bluetooth is
operating in Hotkey Entry Mode.
Hotkey Entry
- use the numeric keypad to
directly access up to 10 of the most commonly
used tests. When operating in this mode the Info
panel will display the
icon and Phot Number
Entry mode will be disabled.
Choose a Test
- available in either Phot Number
Entry or Hotkey Entry modes, the full list of test
parameters is available by selecting Choose a Test
and scrolling using the up/down keys. When the
desired parameter is highlighted, press the OK
key to access the method. Tests are presented in
Phot Number order.
When the required test is selected the Photometer
7500 Bluetooth automatically selects the correct
wavelength and sets additional method parameters
as required.
Test method protocols are defined in detail in the
Palintest Phot Book, supplied with the Photometer
7500 Bluetooth, including the reagents and
accessories that may be required.
When a test is selected, the Photometer 7500
Bluetooth screen will display a number of screens
and options to guide the user through the testing
process, as described in the following pages.
Dilution Factor
If selected in the System menu, the initial screen will
request the defined Dilution Factor to apply to results.
If Dilution Factor is not active this screen will not
be shown.
Results shown on the final screen have automatically
been corrected for dilution prior to display. Corrected
results will also be stored in the log.
Blanking the Photometer 7500 Bluetooth
Blanking the photometer is a key first step in
photometric analysis, effectively removing the
potential entrained sample colour and minor amounts
of turbidity from calculation of analytical results.
To blank the photometer, prepare a Blank cuvette
using untreated sample i.e. sample that has not
been reacted with any reagents. If the sample is to
be diluted or physically treated (filtered for example)
before analysis, use the same dilution/treatment
for the Blank cuvette.
When accessing the test method the Photometer
7500 Bluetooth will request the user to
Insert Blank.
