Profile: St. John Associates, Inc. manufactures fluorometers, luminometers, peptide flask shakers, thermal cyclers and cation exchange resin columns available. We offer filter fluorometers, wrist-action flask shakers, cation exchange columns & resins and amino acid analyzers. Our filter fluorometers provide a versatile means of implementing fluorescence-based techniques in the analysis of discrete samples, in liquid chromatography detection (HPLC), flow injection analysis, and in nephelometry.