Abstract: Samples of bubble films upon gadolinium-gallium garnet substract were dissolved in conc. nitric and 18N sulfuric acids mixture (2:1). The resulting solution was used for following determinations.(a)Chelometric micro titration of iron with EDTA using N-benzoyl-N-phenylhydroxylamine as indicator. Iron was also determined spectrophotometrically with o-phena-nthroline. (b) Calcium was determined chelometrically with cyclohexanedia-minetetraacetic acid (CYDTA), after removal of gallium, germanium and iron by extraction with butylacetate from 7N HCl medium and titration of total rare earths with EDTA at pH5, using xylenol orange as indicator.The latter should be destroyed by saturated bromine water before calcium titration. (c) Germanium was determined spectrophotometrically with fluoronecetyltrimethylammonium bromide (CTAB) at 506 nm. (d) The separation and determination of gadolinium, lutetium, samarium and yttrium: the rare earths were extracted with 0.5% 1-phenyl-3-methyl-4-benzoylpyrazol-5-one in benzene and then separated by reversed-phase column chromato-graphy. The column was filled with silanized silicagel (100-00mesh) impregnated with 2-ethyl-hexylphosphoric acid mono-2-ethylhexylester and the 3 RE were eluted subsequently by HCl of different concentration. They were finally determined spectrophotometrically with arsenazo Ⅲ. The results from two film samples were. given in the paper for illustration.