Troubleshooting Monolayer CV

Hello all,

I'm doing research on single-layer films adsorbed on gold substrates,
and we use CV (poorly) as one of our analytical techniques.

We have a series of quirks and problems that I was hoping some
experienced electrochemists could help me with.

We have a BASi potentiostat, and use BASi brand ag\agcl reference
electrodes. Our cell is composed of the reference, a Pt auxillary,
and the gold film is the working electrode. Electrical contact is
made as follows: the A gold contact ring is soldered to a wire to
attach to the potentiostat. The ring is placed on top of the gold
film working electrode, with a small o-ring to prevent contact between
electrochemical solution and contact ring.

The solution is usually purged H2O with 0.5 M KOH, and we scan to look
for reductive peak potentials, usually -400 to -1.something V.

My problems: The peaks are too broad. Years ago, we had skinny,
sharp, nice looking CVs using this cell and procedure. Now, they are
three times broader than the old data in our laboratory notebooks.
Cleaning the cell in pirrhana solution has had no effect.

There is higher current on the high (less negative) end of the CV than
we used to get. It is so much that in many samples it gives the
appearance of a weak extra peak. Careful cleaning (clean enough for
scanning tunneling microscope studies) seems to have reduced it, but
i'm quite confused.

How can I tell if our reference electrode is fouled? Is there a way
to diagnose potentiostat problems?

Any tips anyone can give me would be appreciated!!!

--Perplexed in Pennsylvania
.

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