1.1 These practices include the extraction and the measurement of chlorophyll a, b, and c, and pheophytin a in freshwater and marine plankton and periphyton. Three practices are provided as follows:

1.1.1 Spectrophotometric, trichromatic practice for measuring chlorophyll a, b, and c.

1.1.2 Spectrophotometric, monochromatic practice for measuring chlorophyll a corrected for pheophytin a; and for measuring pheophytin a.

1.1.3 Fluorometric practice for measuring chlorophyll a corrected for pheophytin a; and for measuring pheophytin a.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use . Specific precautionary statements are given in Section 7.