Knauer Azura ECD 2.1, Instructions Manual

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21 Installation
AZURA® Detector ECD 2.1 Instructions, V6685
Make sure that all parts that are not acid-resistant such as: nylon in-
let filters, column and flow cell are not connected during this step.
5. After flushing with nitric acid, the system must be thoroughly flushed
with demi water. Make sure that no traces of nitric acid are left in the
tubing or pulse dampener (check with pH paper). Flush the system
with HPLC buffer.
If an ISAAC™ reference electrode is used, make sure that the mobile
phase contains at least 2 mmol/l chloride (KCl or NaCl) ions.
6. Before connecting a new column read the manufacturer’s instructi-
ons. Our experience is that thorough pre-conditioning of a column is
always required. Only a pre-conditioned column is electrochemically
clean. If not, the background current may be unacceptably high and
substantial fouling of the working electrode occurs. For reversed pha-
se columns flushing with 50% methanol in water for 3 days at a low
flow rate is highly recommended. Before switching to mobile phase,
flushing with water (10 column volumes) is recommended to prevent
precipitation of buffer salts.
7. Passage of air bubbles through the flow cell will lead to unaccepta-
ble noise levels and ‘spikes’. Therefore, the use of an in-line degasser
is strongly recommended. In our experience, a one-time degassing
step of the HPLC buffer is almost never sufficient. If the ECD 2.1 is
used for reductive ECD (at a negative working potential) additional
steps should be taken to remove oxygen from the mobile phase.
These include degassing with Helium and the use of stainless steel
tubing (impermeable for oxygen).
8. Consult your flow cell instructions for detailed information about the
installation of the flow cell. See Fig. 14 on the next page for referen-
ce. Connect the flow cell to the corresponding cell connector in the
oven compartment. All cell connectors are marked with a label for
identification. For the ECD 2.1, connect the flow cell to the cell con-
nector on the left side marked “Cell 1”.
The cell connector inside the oven compartment is ESD sensitive.
Make sure that the flow cell is OFF when removing or connecting the
cell cable.
Never switch ON the flow cell when: (1) the cell cable is not correctly
connected, (2) the cell is only partly (or not at all) filled with mobile
phase, (3) the outside of the flow cell is wet, particularly the part bet-
ween the auxiliary and working electrode connection, because sub-
stantial damage to the working electrode or electronics may occur.