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 standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.