Dear all, being suddenly confronted with having to analyse Mn-carbonates, especially kutnahorite, I wonder if there are any ideas out there regarding reaction times (with H3PO4), -temperatures, and temperature dependent fractionation factors between these carbonates and H3PO4. I have only a pretty conventional carbonate extraction line, using off-line reaction in temperature controlled baths. Any ideas/suggestions are very much appreciated; thank you all in advance. cheers, Uwe Dr. Uwe E. Horstmann Council for Geoscience P/Bag X112 0001 Pretoria South Africa Tel.: +27 12 841 1361 Fax.: +27 12 841 1278 cell: 082 408 3212 e-mail: [log in to unmask]