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CE‐XRF–initial steps toward a non‐invasive elemental sensitive detector for liquid separations
Author(s) -
Tyssebotn Inger Marie Bergø,
Fittschen Andreas,
Fittschen Ursula Elisabeth Adriane
Publication year - 2018
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201700348
Subject(s) - elemental analysis , x ray fluorescence , analytical chemistry (journal) , chemistry , detector , mass spectrometry , detection limit , materials science , fluorescence , chromatography , optics , physics , organic chemistry
The toxicity, bioavailability, and mobilization of elements within the biosphere is dependent on its species. CE has emerged as a strong separation technique for elemental speciation. Conventionally, CE has been coupled with UV‐vis, C 4 D, PIXE (proton‐induced X‐ray emission), and ICP‐MS. UV‐vis and C 4 D are not elemental sensitive detection methods, PIXE requires the etching of the detection window resulting in a very brittle capillary, and ICP‐MS is an expensive large footprint instrument. Here, we aim to develop an elemental specific detector, XRF (X‐ray fluorescence spectrometry), for use with CE. A custom‐built micro‐XRF was tested and static LODs were determined for 19 elements (Ca‐U) with both unmodified (20‐926 ppm) and modified capillaries (20‐291 ppm). A custom‐built CE was combined with the micro‐XRF and separation of Ca 2+ and Co 2+ was obtained. Sr 2+ coeluted with Ca 2+ in the mixture, but because of the elemental sensitivity of XRF, the Sr and Ca signals could be separated. After successful testing of the micro‐XRF, the feasibility of using a low‐cost X‐ray source and detector was tested. Even lower LODs were obtained for Ga and Rb, showing the feasibility of a smaller, low‐cost XRF unit as an elemental specific detector. However, the buffer selection that can be conveniently used with XRF is currently limited due to capillary corrosion, likely correlated to radiolysis.