Open AccessOn the Problem of Sample Preservation by Freezing
Author(s) -
Rinne Dieter,
Schmitt Petra
Publication year - 2004
Publication title -
acta hydrochimica et hydrobiologica
Language(s) - English
Resource type - Journals
eISSN - 1521-401X
pISSN - 0323-4320
DOI - 10.1002/aheh.200100513
Subject(s) - sample (material) , sampling (signal processing) , chemistry , chloride , value (mathematics) , mineralogy , analytical chemistry (journal) , statistics , chromatography , hydrology (agriculture) , mathematics , geology , geotechnical engineering , physics , organic chemistry , optics , detector
During routine analysis of running water samples differences of the analytical results of water‐soluble anions were observed between analysis carried out immediately after sampling and after storage of the cooled/frozen sample. This phenomenon was investigated for some years with the “model ion” chloride. A high number of samples (ca. 210) were analysed over three years with different analytical methods, and by alteration of the sample containers the discrete physical influence of the wall effect of the sample vessel could be worked out definitely. No significant differences occur with the mean value of the year but the single values have high differences in the positive or negative direction. Assuming a similar behaviour of other water constituents when preserved by freezing the analytical values had to be looked at very critically.