A technique is presented for separation and collection of amino acids and peptides using a microcolumn amino acid analyzer. By use of the program and the column selection valve of the amino acid analyzer, and without any modification of the instrumentation, the stream of the eluate is diverted into the reaction coil and absorbance is recorded at regular intervals. The rest of the eluate is collected in a fraction collector for further characterization of the separated peptides. Splitting ratios can be varied by simple alteration of the program. Small amounts of material (1 to 2 nmol) are needed for monitoring the separation and collection of the eluate.