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Full-Text Articles in Physical Sciences and Mathematics
A Comparative Study Of Photomultiplier Tubes And Charge Coupled Devices In Glow Discharge-Optical Emission Spectrometry, Robert James Broadwater
A Comparative Study Of Photomultiplier Tubes And Charge Coupled Devices In Glow Discharge-Optical Emission Spectrometry, Robert James Broadwater
Masters Theses
This Masters Thesis compared two glow discharge-optical emission spectrometers designed around two different types of detectors: the photomultiplier tube (PMT) and the charge-coupled device (CCD). The two instruments compared were the LECO SA2000 (PMT-based) and the LECO GDS500a (CCD-based). Detection limit, dynamic range, precision, accuracy, and drift were determined to compare the detection systems between 165 and 450nm.
The PMT-based system outperformed the CCD-based system in all five of the categories studied based on the initial protocol. However, it was shown that improvements could be made in four of the five categories studied by exploiting the CCDs ability to monitor …
Capillary Electrophoretic Separations Of Metal Ions, Elena Hofman
Capillary Electrophoretic Separations Of Metal Ions, Elena Hofman
Masters Theses
Transition-metal (Zn(II), Co(II), Ni(II) and Cu(II)) ion separation was studied using 8-hydroxyquinoline-5-sulfonic acid and 2-methyl-8-hydroxyquinoline ligands with surfactants (cationic and anionic) by capillary electrophoresis under a variety of conditions (like pH, ionic strength, voltage and ion, ligand and surfactant amounts) and has debuted a clear separation mechanism. With cationic surfactants, ligands compete with capillary surface silanols for the metal ions; with anionic surfactants, ligands, silanols and micelles compete.
An empirical parameter, Ke, (electrophoretic-mobilities based) rationalizing the separation was proposed, experimentally analyzed and supported; it provides a silanol group per cm2 value of the capillary surface, an equilibrium …