The present invention relates to the preparation of a sample. Preferably, the sample is a sample to be analyzed, for example for ingredient content, etc. Preferred samples include foods, cosmetics, paints, coatings, adhesives, tanning agents, fabrics, chemical compositions, dyestuffs, samples subject to forensic studies, etc. Samples prepared according to the invention method are digested in sulfuric acid, nitric acid, and one or more fluoride salts selected from LiF, NaF, RbF, CsF and KF and then preferably subjected to analysis for metal content, etc, for example using atomic absorption (“AA”) and inductively coupled plasma (“ICP”).