A NEW METHOD AND INSTRUMENT FOR THE QUANTITATIVE DETERMINATION OF CHLOROPHYLL

Abstract

Light from a 6-volt lamp, rheostat-controlled, is passed through a red glass color filter, which converts it into those wavelengths most strongly absorbed by chlorophyll. The chlorophyll, as the water-soluble K salt, is contained in a small glass absorption cell. The filtered light passes through the absorption cell containing the sample to be determined, and falls upon the face of a photoelectric cell. The intensity of light transmitted is measured by means of a microammeter, whose readings are an exact indication of the amount of chlorophyll present. By calibration of the instrument with known solutions, the calibration curve is found to be an hyperbola with equation XY=4, where X is relative light transmitted, and Y is grams of chlorophyll per 100 cc. Method eliminates personal errors prevalent in colorimetric and spectrophotometric methods, and allows detection of much smaller differences in concentration.