In this communication, the methods for miorodetermination of reducing sugars and aliphatic secondary amines have been reported. For analysis of reducing sugars, Benediot's reagent was used. as oxidizing agent. The Cu₂O foamed was filtered, washed and dissolved in nitric acid and determined by atomic absorption speotrophotometry. From the amount df copper found, the quantity of reducing sugar in the sample was calculated. An universal calibration curve may be used. With 1~8 mioromoles of samples, the percentage of recovery of this, method. was better than. 98% (see Table 1 in the Chinese Text).The effect of interference ions on the results of, analysis and the optimum conditions were discussed.