PRESERVATION TECHNIQUES FOR ANALYSIS OF ORGANIC-COMPOUNDS IN WATER SAMPLES - A REVIEW

Sample storage is a necessary and critical step in water analysis. Dur ing the storage, many changes in the sample may occur; namely chemical and physical reactions, microbiological degradation and the nature of sample-container may produce analyte losses. To minimize changes betw een collection and analysis, standard methods contain a part within wh ich preservation techniques are described, e.g. chemical addition, tem perature control, choice of sampling container and holding times. A re view of some results published in recent studies show there are no abs olute rules to prevent all the analyte modifications and to define a h olding time optimized for each preservative technique. We have to take into account the character of the samples and the properties of the a nalytes to validate the preservation techniques. Generally, if immedia te analysis is not possible, rapid addition of the extraction solvent and storage of sample extracts at 4-Degrees-C is recommended. For the future, field extraction using SPE disks may be a way to improve the s torage stability of organic compounds.