Specific Ultraviolet Absorption

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Ultraviolet light spans a narrow range of wavelengths of the EMR spectrum EMR spectrum subtypes Specific UV absorbance (SUVA) wavelengths have analytical uses in providing metrics to "measure the aromatic character of dissolved organic matter"[1] by detecting density of electron cloud conjugation which is associated with aromatic bonds (ibid).

To derive SUVA, first, UVC light (cf. EMR spectrum subtypes) at 254 nanometers (nm), or 280 nm,[2] is measured in units of absorbance per meter of path length, often the sample must be diluted with Ultrapure Water as absorbance can be very high.[3] As increasing dissolved organic carbon concentration increases absorbance in the UV range, the UV light has to be normalized to the concentration of dissolved organic carbon in mg per L to ascertain differences in the aromatic quality of the water.

Aromatic character is used in the study of dissolved organic matter, from mineral soils, or organic soils, to use as an assay to whether or not dissolved organic carbon in the water is labile, a ready source of energy, or is from a relatively old source of carbon (recalcitrant). However, although a good indicator of aromaticity, caution must be used with determination of reactivity.[4]

Measures of water purity often rely on measuring turbidity, not aromaticity.

References[edit]

  1. ^ Bourbonniere, 2009
  2. ^ Bourbonniere, 2009; Holl et al., 2009
  3. ^ Chantigny et al., 2008
  4. ^ Weishaar et al., 2003

Sources[edit]

  • Bourbonniree, Richard A. 2009. Peat Water Chemistry. Canadian water resources journal. 34(4)
  • Chantigny, MH., Angers, DA., Kaiser, K., Kalbitz, K. 2008. Extraction and Characterization of Dissolved Organic Matter. Soil Sampling and Methods of Analysis. MR. Carter (Ed.) Canadian Society of Soil Science, Lewis Publishers, Ann Arbor, MI.
  • Holl BS, Fiedler S, Jungkunst HF, Kalbitz K, Freibauer A, Drosler M, Stahr K. 2009. Characteristics of dissolved organic matter following 20 years of peatland restoration. Science of the total environment. 408(1):78-83.
  • Weishaar, J. L., G. R. Aiken, B. A. Bergamaschi, M. S. Fram, R. Fujii, & K. Mopper. 2003. Evaluation of Specific Ultraviolet Absorbance as an Indicator of the Chemical Composition and Reactivity of Dissolved Organic Carbon. Environmental Science & Technology 37 (20): p 4702-4708. DOI: 10.1021/es030360x.