4.1 Calcium Carbonate (CaCO₃) buffered formalin (3 to 5 %) can be used as a permanent preservative for zooplankton. Lugol's iodine solution can be used to preserve zooplankton for up to one year. Thirty percent ethanol, 30 % glutaraldehyde, or 25 % vinegar (can use 3 % acidic acid solution) can be used for more temporary storage and preservation of zooplankton samples. A 25 % vinegar solution is preferred to preserve soft-bodied planktonic coelenterates.

1.1 This practice describes the proper procedures for preserving zooplankton samples with either formaldehyde, ethanol, glutaraldehyde, Lugol's iodine solution, or vinegar (acetic acid).

1.2 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.