Antec Scientific VT-03, Руководство пользователя

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32 VT03 flow cell user manual, ed. 8
5. Use the drill to pack the wool from above through the KCl solution into
the channel of the salt bridge, compress it firmly, but not too much, since
electrical conduction is essential.
6. Remove the cap.
7. Fill the salt bridge completely, add some KCl crystals out of a saturated
solution to ensure prolonged saturation.
8. Place the small Vyton ring over the Ag/AgCl electrode and slowly insert
it, in an angle of 45
o
into the salt bridge. Make sure not to enclose an air
bubble.
9. Tighten the black swivel such that a small droplet appears at the end of
the salt bridge, but do not over-tighten the swivel.
10. Flush the complete, mounted REF with demi-water, dry it with a tissue,
but keep the cotton wool frit soaked.
11. Carefully inspect the REF visually for trapped air bubbles, otherwise
remove them (go back to step 7 or if necessary step 1).
When not in use, please store the REF with the cotton wool frit
immersed in a saturated KCl solution to prevent drying out.
Working electrode
Cleaning of the working electrode block is necessary if the electrode surface
has been electrochemically changed. This may be due to fouling by oxidation
(reduction) reaction products. Excessively high currents also may change the
electrode surface. This is noticed by a strongly decreased sensitivity after
prolonged use.
As a rule of thumb: only polish if the surface of the working electrode lacks its
mirror-like finish, which cannot be restored by wiping the electrode surface
with a tissue wetted with ethanol or acetone.
Decreased flow cell performance
Use proper eye and skin protection when working with solvents.
Several actions can be taken at decreased flow cell performance. Avoid
unnecessary polishing, take the next step only if the previous was not
successful.
1. Electrochemical cleaning of glassy carbon WE: In the pulse mode let the
potential jump b1 and -1 V for 10 min. Settings: t1 = 1000 ms, t2
= 1000 ms, t3 = 0 ms, E1 = +1V, E2 = -1V.
2. Wiping the electrode surface with a tissue wetted with ethanol or acetone