Thin layer chromatographic method for determining plant pigments in marine particulate matter, and ecological significance of the results

Abstract

Thirty to 100 liters of sea water sample containing MgCO₃ powder was filtered through a glass fiber filter in order to collect particulate matter. Soon after the filtration, this glass fiber filter was kept in a deep freezer (-20°C) for later use. The following pigment analysis was carried out within a week. Plant pigments in the collected particulate matter were extracted with 90% acetone in a dark refrigerator. Pigments in the acetone extract were separated by thin layer chromatography using a mixture of cellulose powder and soluble starch as an adsorbent. The developing solvent was 1.2% n-propanol in petroleum ether. According to this procedure, 9 kinds of pigments were fractionated. Each of the fractionated pigments was eluted with 90% acetone and determined by measuring fluorescence of the acetone extracts after acidification with a small amount of hydrochloric acid. The analyses of sea water samples from the central Pacific showed the following facts: (1) Vertical distribution of chlorophyll a had a peak at a depth of 100m or 150m and its amount remarkably decreased with depth in parallel with the total pigments. (2) The percentage of chlorophyll a in the total pigments was more than 60% for the sea water samples examined, even at the depth of 1, 000m. (3) The absence of phaeophytin a was made clear for the samples examined.