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Title: Trace analysis by molecular spectroscopy.
Author: Zeng, Zuotao.
Awarding Body: University of Huddersfield
Current Institution: University of Huddersfield
Date of Award: 2001
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This thesis describes new analytical methods for trace or ultra-trace analysis by molecular absorption and emission spectroscopy. The initial part of the thesis is devoted to an introduction to molecular electromagnetic absorption spectroscopy and molecular fluorescence. The principles, advantages and limitations of spectrophotometric and fluorimetric measurement are discussed. The concepts of enzymes and their applications in analytical chemistry are also expounded. Two organic compounds, 5-( 4-arsonophenylazo )-8-(p-toluenesulfonamido)quinoline (APTSQ) and 5-(p-methoxyphenylazo)-8-(p-toluenesulfonamido) quinoline (MPTSQ), have been synthesised and used as new chromogenic anellor f1uorogenic reagents. Five specific, highly sensitive, simple, precise and inexpensive novel analytical methods have been developed: (1) A spectrophotometric method is described for the determination of cobalt. The maximum absorbance is at 582 nm with a molar absorptivity of 1.18 x 1 as I mor' cm-1 . Beer's law is obeyed for cobalt concentrations in the range 0-0.5 J.l.g mr'. (2) A fluorimetric method for the determination of cobalt is proposed. The fluorescence intensity is measured at Aex 287 nm and Aem 376 nm. The response is linear up to 25 ng mr' and the detection limit is 0.002 ng mr'. The mechanism of the fluorescence reaction has been investigated. (3) A flu~ri~etric method is proposed for the d~ter~i~~tion of H202. The response IS linear up to 12.2 ng mr H:t>2. The detection limit IS 0.16 ng mr'. (4) An enzymatic assay for glucose by spectrofluorimetry is described. The fluorescence intensity is proportional to the concentration of glucose up t0180 ng mr'. A detection limit of 5.4 ng mr' was obtained and allowed the determination of glucose in an extremely small amount of serum (O.5J.1.I) and urine (1 J.l.1). (5) A fluorimetric method for the determination of iron is proposed, based on the reaction between iron(III) and MPTSQ in the presence of cetyltrimethylammonium bromide. The fluorescence intenSity (Aex=317 nm, A.em=534 nm) is linear up to 170 ng mr' with a detection limit of 0.12 n9 mr'. An investigation of the mechanism of the fluorescence reaction has been made. The applications of the proposed methods for the determination of the concerned analytes at low levels in biological, environmental, pharmaceutical or beverage samples are also reported.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Analytical chemistry Chemistry, Analytic