ANALYTICAL SPECTROSCOPIC CAPABILITIES OF OPTICAL IMAGING CHARGE TRANSFER DEVICES.

摘要

The investigations described within this dissertation foretell the imminent revolution in optical analytical spectroscopy and conclusively demonstrate superior qualitative and quantitative analysis performance of a new system for atomic spectroscopy as compared to present, state-of-the-art instrumentation. The advent of a new class of multichannel detectors, the silicon charge transfer devices (CTDs) is shown to significantly impact ultraviolet, visible, and near-infrared analytical spectroscopy. An overview of the operation, characteristics, and performance of CTDs is presented including the results of the characteristics of a CTD detector system developed during these investigations. Theoretical comparisons of the performance obtainable in spectroscopic systems employing CTD detectors versus conventional detectors, including equations identifying the factors limiting sensitivity, demonstrate that CTDs offer superior performance. The second part of this dissertation describes the application of a particular CTD, the charge injection device (CID), to a very challenging spectroscopic problem, as far as light detection is concerned, simultaneous multielement analytical atomic emission spectroscopy. This widely employed technique for qualitative and quantitative elemental analysis requires sensitive and wide dynamic range detection of a large number of spectral resolution elements. This research resulted in the development of a novel echelle spectrometer employing a CID detector which has been demonstrated to be capable of solving many of the problems currently encountered in analytical atomic spectroscopy. The system achieves superior sample throughput rates, flexibility, accuracy and precision as compared to sequential spectrometers employing a single detector and to polychromators employing relatively few fixed detectors. The research included the development of a unique method of operating the CID, which is used to cope with the very wide dynamic range signals encountered in atomic spectroscopy, and has resulted in a spectroscopic instrument able to qualify simultaneously major and trace components of extremely complex samples with greater sensitivity and accuracy than possible with conventional instrumentation. New, very flexible, and extremely rapid methods of qualitative analysis have also been developed which virtually eliminate the possibility of spectral line misassignment. The atomic emission spectroscopic system is applicable in a variety of analytical areas as diversified as high sensitivity detection of near infrared spectral lines and element-specific detection of chromatographic eluents.