Optimising the storage and extraction of chlorophyll samples

The effect of different methodological steps on the analysis of chlorophyll a (chl a) was tested with algae cultures and Baltic Sea water. Selected experiments were tested with ANOVAs for significant differences between treatments. The results of the experiments led to the following recommendations: the sample volume should be low so that filtration takes no longer than 10 min. Extracts rather than filters should be stored if storage of the samples at −20◦C is required. However, quickfreezing in liquid nitrogen is recommended. The extraction efficiency was much better in 96% ethanol than in 90% acetone – extraction in the latter solvent requires the filters to be homogenised. The extraction time has no significant influence within a range of 3 to 24 hours if the recommended 96% ethanol is used.