Inductively coupled plasma atomic emission spectroscopy using charge injection device detection.
AuthorPilon, Michael Joseph
AdvisorDenton, M. Bonner
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractA unique echelle spectrometer system employing charge injection device (CID) array detectors for use in inductively coupled plasma atomic emission spectroscopy (ICP-AES) is described. The echelle spectrometer described offers numerous advantages over previous systems including improved light throughput and extended wavelength coverage including the vacuum-ultraviolet (VUV) down to 165 nm. Several improvements in CID array detector technology are also described. Low exposure level linearity is improved and full well capacity is increased by fabricating the CIDs with <100> silicon as opposed to <111> silicon. Low sensitivity in the far-ultraviolet (far-UV) has been considered a major disadvantage when using silicon based detectors due to absorbance in the overlying gate structure of the devices. The problem has been circumvented by utilizing a wavelength conversion phosphor to improve the effective sensitivity in the far-UV. The read noise of the CID has been reduced by a factor of 3 by utilizing a preamplifier on every row of the device. Utilization of this system for ICP-AES yields numerous advantages over conventional photomultiplier tube (PMT) based systems. Elemental detection limits comparable to or better than those obtained on PMT based instrumentation are achieved in the UV and visible regions. Sensitivities at wavelength less than 200 nm are degraded by a factor of 5 relative to PMT based systems due to decreased echelle grating efficiency in that wavelength region. In most cases, the advantages of continuous wavelength coverage provided by CID array detectors outweighs any loss in sensitivity. Operating parameters including precision, resolution and background correction are also discussed. Analysis of both the National Institute of Standards and Technology (NIST) Standard Reference Materials (SRM) 1643b and 1646 demonstrates that the system is capable of the simultaneous determination of a large number of elements at a large number of wavelengths with a high degree of accuracy even in spectrally complex matrices.