17 |
P a g e
Total scan
time to
3 min
(Adjust these settings later depending on your pathlength setting.)
Use the Monitor Parameter function icon to set integration time of the TIDAS S 300 UV/VIS. A
maximum of 45000 cts should be observed, when using MilliQ water in the UltraPath 2 sample
as a reference. Typical integration times are 100 to 2000ms.
Sample collection
1.
Close the shutter at the light source (14) and take a
Dark Scan
2.
Open the shutter (14) at the light source and press the
Reference Scan
icon to take a
reference signal.
3.
Press the
Scan Start
icon to start a continuous scan.
4.
Start the pump and draw sample into the UltraPath 2
sample cell (See “How
to fill the
UltraPath 2
sample cell” f
or details).
5.
Introduce an air bubble of approximately the length of the Injector tubing at the liquid input
of the UltraPath 2 sample cell and draw the sample into the cell.
6.
A very high absorbance signal will be observed until the sample cell is filled with the sample
solution, then a steady signal will be present. This may take between 15 seconds and 1 minute,
depending on the pathlength used.
It is good practice to measure the baseline with reference solution at the beginning and the
end of the measurement cycle. Thus, introduce a second air bubble and draw a second draw
reference solution into the sample cell until a stable baseline signal has been reached. After
the signal has returned to the baseline, stop the continuous measurement cycle by pressing
the
Start Scan
icon.
NOTE:
1.
Sample Cell Preparation
It is good practice to fill the UltraPath 2 at the beginning of each measurement cycle with clean
deionized water and measure the Light intensity throughput of the cell for quality reference.
This allows the user to determine if the sample cell is contaminated and needs cleaning.
2.
Seawater
WPI highly recommends using salinity matched reference solutions, when working with
seawater to avoid absorbance baseline offsets caused by refractive index variations when
reference and sample solution have different salinities.
