14.4.9.2 Inserting a new cotton wool frit
To insert a new cotton wool frit:
1. Place the salt bridge with the frit hole downward on a glass plate and add a few drops of
saturated KCl solution.
2. Pull a small plug of wetted cotton wool into a thin string (using two tweezers, for example).
3. Place one end of the cotton string into the body and, using the sb REF tool, push the wool
piece by piece from above through the KCl solution into the frit channel.
4. While holding the body on the glass plate, compress the cotton firmly. Ensure that you do
not push the cotton out of the body through the narrow end.
Result:
The REF is now ready to be refilled
14.4.10 Assembly of the flow cell
Warning:
The surfaces of the inlet block, working electrode, and spacer should be dry
when assembling the flow cell. Unnecessary moisture inside or outside the flow cell
increases the noise level considerably.
To assemble the flow cell:
1. Take the working electrode disk and press it in its silicone holder. Try not to touch the
active middle surface.
2. Clean fingerprints off the spacer, AUX, and WE surfaces using a tissue wetted with
acetone.
3. Place the spacer on the inlet block, with the two holes over the two pins.
4. Screw the retaining ring on the inlet block.
Warning:
To prevent the spacer from slipping off the pins, keep the flow cell
Figure 14–11: Assembling the flow cell (Page 120)
,
while mounting the retaining ring and WE assembly.
5. Install the working electrode assembly and verify that the groove in the assembly aligns
with the internal pin (which prevents it from turning).
6. Fix the assembly in the cell body with the electrode swivel nut. Do not apply too much
force; finger-tight should be enough force to make a leak-free seal between the WE, inlet
block, and spacer.
The flow cell is ready for connection to the LC system
December 16, 2021, 715007395 Ver. 00
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