Dear All, I am doing some 15-N work with ammonium and would be happy if any one had some tips with one or two points that are concerning me. 1) Washing glassware: Acid or weak alkali rinse? I normally do an acid rinse in the washing machine but this seems like a poor thing to do with NH4+, any thoughts? 2) Baking KCl to remove NH4+: How long and what temperature? One or two people I have chatted with have suggested that baking the KCl could reduce my blanks (I work in soils) but I have yet to find a reference or method. Many thanks for your time. Yours Andrew Dr A.M.Johnston DSPE Scottish Crop Research Institute Invergowrie Dundee DD2 5DA Scotland Tel No: (44) 1382 562731 ext 3732 Fax No: (44) 1382 562426 email: [log in to unmask] email: [log in to unmask]