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- Dahlén, Johan, 1969-
(författare)
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Capillary electrophoresis and multivariate calibration in the analysis of natural waters
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work was to explore the applicability of capillary zone electrophoresis (CZE) and multivariate partial least squares (PLS) regression in the analysis of organic compounds and inorganic ions in natural waters. A new CZE application was developed to analyze low molecular weight (LMW) organic acids. A UV-absorbing co-ion (trimellitic acid) was used to allow indirect detection, and a cationic electrolyte additive (Ca2+) was employed to optimize separation selectivity. The method was applied to determine LMW organic acids in surface waters and precipitation samples. The use of CZE to characterize humic substances was evaluated. Small, but significant, differences in electrophoretic mobility were observed between the analyzed humic samples. A new CZE method using on-capillary complexation with 2,4,6-tri(2'-pyridyl)-1,3,5-triazine (TPTZ) was developed to analyze FE(II) in natural waters. The procedure is easy to use and requires a minimum of sample pretreatment. Multivariate calibration by means of PLS regression, using spectroscopic data in the UV/VIS range, was applied to calculate models to estimate the molecular weight of isolated aquatic fulvic acids. A combination of PLS and UV/VIS spectroscopy was also employed to establish models to predict levels of nitrate and non-purgeable organic carbon (NPOC), as well as other common parameters of groundwater quality. In conclusion, the examined methods are highly useful for analyzing natural waters-CZE due to its extreme flexibility, and PLS due to its ability to extract information from complex data matrices.
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