Probleme der spektrophotometrischen Chlorophyllbestimmung

Abstract

AbstractFor the determination of the contents of chlorophyll a and phaeopigment a in sediment samples the method according to LORENZEN with its principle and the error sources is discussed in detail. The acidification required for the determination of the phaeopigments should be carried out on a final concentration of 0.006 mol/l acid. As an extracting agent, such a quantity of acetone has to be added to the sediment sample that a final concentration of 90 % acetone will be obtained with the interstitial water being taken into account. By an extraction done twice 90 % of pigments are extracted. Methanol as an extracting agents is unsuitable for several reasons mentioned. Exposure to light at more than 1 W/m2 results in a high rate of chlorophyll degradation, the same effect being shown by increased temperatures. Between the trichromatic chlorophyll determination according to JEFFREY and HUMPHREY and the determination according to LORENZEN exists the linear relation chl. a (J. and H.)=chl. a (L.)+0.6. phaeo. a (L.). The procedure of the determination of chlorophyll a and phaeopigment a according to LORENZEN is described in a detailed representation.