4• Startup
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4.1.2 ED Amperometry Cell Operating Precautions
• To prevent electrode contamination:
• Run only clean, filtered samples.
• Prepare all eluents with high purity ASTM Type I
(18 megohm-cm) filtered and deionized water.
• Avoid contamination of the cell with incompatible eluents.
• Never apply potential to the electrode unless a stream of eluent or
water is flowing through the cell.
• Do not allow the reference electrode to dry out. Make sure that eluent
is pumped continuously through the cell. If the cell will not be used
for a short time (less than 2 days), disconnect the tubing from the inlet
and outlet fittings and install fitting plugs. For longer shutdowns, see
Section 6.4
.
• Be careful to keep the polished surface of the amperometry cell body
clean and dry when not in use. The gold, spring-loaded (pogo) contact
must also remain clean and dry. If a salt bridge forms, it can cause an
electrical short between the working electrode contact and the cell
body.
• If the conventional (nondisposable) working electrode becomes
discolored or if you notice a degradation in performance (baseline
noise, tailing peaks, etc.), polish the electrode as instructed in
Section 9.24.3
.
• Over the lifetime of the conventional working electrode, the surface
may gradually become pitted or receded. Receded electrodes can be
repaired by sanding with 600 grit sandpaper. Continue sanding until
the metal surface is again flush with the Kel-F electrode block
surface. Then, polish the electrode with coarse and fine polishing
compounds as instructed in Section 9.24.3
.
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