Abstract: The geological sample (0.100 0 g, with grain size smaller than 0.074 mm) was mixed thoroughly with 0.100 0 g of a buffer mixture composing K₂S₂O₇, NaF, Al₂O₃, C and GeO₂ in the mass fraction ratio of 23:20:45:12:0.007 in which Ge acting as internal standard. The sample mixture was then added to the lower electrode and tightened. Diameter of the upper electrode selected was 4 mm. Ag, B and Sn in the sample were determined with direct reading atomic emission spectrometer under the selected conditions (excitation current:14 A; exposure time:35 s). CRM's were used for preparation of calibration curves. Values of detection limit (3s) found for the 3 elements were 0.01, 0.54, 0.21 μg·g^-1 respectively. The proposed method was tested by analyzing 8 CRM's giving results in consistency with the certified values and values of RSD's (n=12) in the ranges of 2.1%-16% (for Ag), 5.4%-12% (for B) and 5.5%-9.1% (for Sn).