Dear Dachun and listmembers,

I don't know the amount of hydrochloric acid you used, but I
suppose that high pH waters would need more than some drops.
The most concentrated HCl contains cca. 64 % H2O, so this
method would bring industrial water into the sample. Is there a
reason why 100% H3PO4 is not used for this purpose?

Cheers,
Attila

Dr. Attila Demeny
Laboratory for Geochemical Research
Hungarian Academy of Sciences
Budapest, Budaorsi ut 45, H-1112, Hungary
tel/fax: 36-1-319-3145
e-mail: [log in to unmask]