Fitting a pre-established region-specific Parallel Factor Analysis (PARAFAC) model to new dissolved organic matter (DOM) samples has become a popular approach in DOM studies. A key step during the development of the pre-established model is to identify fluorescence fingerprint, i.e. the number of fluorescent DOM (FDOM) components as well as their excitation and emission spectral features. In practice the samples to use for the model development may not be measured immediately after sampling and will instead be stored for relatively long time, thus raising a question whether the storage would change the intrinsic fingerprints. In this study, two PARAFAC models were separately developed and validated for the same set of surface water DOM samples from an estuary and its river, immediately after sampling and after 9-month storage respectively. The fingerprint did not change after the storage, regardless of the change of some components intensity. The findings in this study highlighted that DOM samples stored using a simple protocol (i.e. filtration to 0.45 μm pore size without any preserves and placed at 4 °C in dark under airtight conditions) for a few months would not change fluorescence fingerprints for PARAFAC and broaden our understanding in application of PARAFAC to DOM studies.
- Daliao River Estuary
- dissolved organic matter
- parallel factor analysis
- spectral features
- First received 15 December 2014.
- Accepted in revised form 10 July 2015.
- © IWA Publishing 2015