Knauer Azura ECD 2.1, Instructions Manual

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88 Troubleshooting
AZURA® Detector ECD 2.1 Instructions, V6685
well-functioning VT-03 flow cell in an ideal (U)HPLC set-up. The noise ge-
nerated via the dummy should be less than 2 pA if the filter of the control-
ler is set to off, provided that the dummy is within the fully closed Faraday
shield at the same position as the flow cell.
Table XI. Dummy cell test settings.
Parameter Setting
Cell potential 800 mV
Oven 35 °C, stable
Filter Off
Range 1 nA/V
Test criteria:
ƒ
I cell = 2.67 +/- 0.05 nA
ƒ
Noise < 2 pA
The results (cell current and noise) of the dummy cell test should be
within the above mentioned test criteria. If the current values for Icell
and noise are not within the criteria it is an indication that something
could be wrong with the detector hardware. Please consult your
local representative.
Internal dummy cell
The ECD 2.1 also has the option to run a so-called internal dummy cell
test. This exclusively checks the performance of the electronic circuit
boards (amplifier circuitry) only, so it excludes the cell cables and the
external dummy flow cell. From the MAIN screen DIAG can be selected to
enter the DIAG screen, followed by selecting NOISE. This activates a timer
in the NOISE screen, and after 5 min stabilization auto zero is activated
and the dummy cell test is ready. Noise of the internal dummy cell can be
measured at the output. As with the external dummy cell the noise should
be better than 2 pA. Detector settings in the NOISE screen are the same
as in the external dummy cell test with the exception of the oven tempe-
rature. Temperature is switched off.
Fig. 73
Stabilizing cell current
In the NOISE screen, the cell current is shown and the output voltage.
P l e a s e w a i t N O I S E
43
s t a b i l i z i n g c e l l c u r r e n t
t i m e r e m a i n i n g 0 5 : 0 0
P R E V