Scott:

You do not analyze for Peroxide, as it is gone essentially instantaneously,
either by oxidizing the Cuprous ion produced in the etch reaction, or by
 decomposition, as it is not real stable in Cupric Chloride solution.   You
normally control Peroxide by measuring the Oxidation/Reduction Potential
(ORP).  If you are not doing this, you can measure the absence of Peroxide,
by measuring the Cuprous ion content.  (And incidently, the rule of thumb is,
if you can measure the presence of Cuprous, you have too much!)

Measuring the HCl content is reasonably easy, at least once you know the
procedure.  Why not send me your fax number, and I will fax you procedures
for the HCl content, as well as Cuprous ion analysis procedures.

Also, if you have access to the www, check out the website we sponsor,
http://www.pcbfab.com for a discussion that will likely give you more than
you ever wanted to know about Cupric Chloride etching.

Best regards,

Rudy Sedlak
RD Chemical Company
[log in to unmask]
fax 415-962-0370