Spatial and spectroscopic imaging for chemical analysis utilizing scientifically operated charge transfer device array detectors.

Abstract

The use of scientifically operated charge-transfer device array detectors are investigated for several spatial and spectroscopic optical imaging applications in chemical analysis and are described in this dissertation. The improved optical detection capabilities of this class of solid state detectors, made up of both charge-injection and charge-coupled device (CCD) detectors, offers a number of significant advantages over previous optical detection technologies utilized for these applications. The results obtained from the investigation of the use of a scientifically operated charge-injection device based echelle spectrograph system for the on-line monitoring of heteropoly acids, after chromatographic separation, for the indirect determination of phosphate, silicate and arsenate are presented. The obtained results represent an improvement over direct aspiration into an emission source for these nonmetals, showing excellent linearity over three orders of magnitude. Results from the evaluation of a scientific CCD detector based technique for the luminescence imaging of latent fingerprint residues on glass and paper, after chemical treatment with fluorescence enhancement agents, is presented. The use of a scientific CCD for fingerprint imaging is demonstrated to be a viable alternative to those methodologies requiring the use of high power laser excitation sources and photographic film imaging. Results of the use of a scientific CCD for the spectroscopic determination of seawater pH are also presented. Discussion is given to general system design, detector characteristics and modes of operation which will result in a ship board instrument capable of making both sensitive fluorometric and precise absorbance measurements. Additional investigations presented include the use of a scientific CCD for the in situ detection of DNA fragments separated in agarose electrophoretic slab gels and aflatoxins separated on thin-layer chromatographic plates. Scientific CCD detection, in contrast to previous optical detection techniques, is demonstrated here to provide for a competitive means of component detection in these media, offering significant advantages in speed, precision and ease of analysis.