I am looking for the precise steps one takes in using calcein to
measure calcium in urine. There are (at least) two ways of doing this.
The first is by a method called titration, and I am not interested in
this method. The other is via spectroscopy or fluoroscopy or some
other related technology. Sigma-Aldrich makes calcein, but were unable
to provide this information.

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Clarification of Question by dgc-ga on 28 Apr 2003 09:15 PDT

Note to andrewxmp-ga. See my comment below.

-dgc-ga

Hey.  I was going to officially answer this, but it was all pretty
confusing, and I wouldnt want to give you an incorrect answer.

As you mentioned, fluorescence spectroscopy is the technique used to
measure calcium.  In this technique, calcein is the reagent that is
directly measured.

“In alkaline conditions, Calcein complexes with calcium to form
fluorophore with an excitation of 450nm and emission of 520nm.”

So, I would check out [
http://homepages.wmich.edu/~rsung/files/bioAna.pdf ]on page 46.  It
outlines a proceedure used quite nicely.

Also, check out: http://www.gfz-potsdam.de/pb4/pg2/equipment/xray/xray-lab.html
for more general info.

Hope this helps...
-Andrewxmp

The comment from andrewxmp-ga answered my question. I want to credit
it for payment. How do I do this? Thank you.

Try posting in the Request for Clarification saying that you wish
Andrewxmp to post his answer, then he will be informed by email. Hope
that helps.