Evaluation of a vidicon scanning spectrometer for ultraviolet molecular absorption spectrometry

Milano, Michele; Pardue, Harry L.

doi:10.1021/ac60351a020

Cited by 55 publications

(28 citation statements)

References 9 publications

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“…In such a film on -3 M NaOH, the area per molecule at a surface pressure of 5 dynes/cm is 40 Á2, while on 10~3 M HCL, it is 98 Á2, the film being much more compressible. These values are reasonable in view of the molecular structure and ionization of the film on the acidic subphase (7).…”

supporting

confidence: 73%

Derivative spectrometry with a vidicon detector

Cook¹,

Pardue²,

Santini³

1976

Anal. Chem.

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supporting

confidence: 73%

Derivative spectrometry with a vidicon detector

Cook¹,

Pardue²,

Santini³

1976

Anal. Chem.

Self Cite

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“…Thus, according to Table 11, an M analysis of these noisy data should give an essential rank m = 2; that is, A(2) in Equation 4 should fit the data to within its random noise. Figure 10 shows the surface A(z,.…”

Section: Effect Of Random Measurement Errorsmentioning

confidence: 99%

“…The development of sophisticated computer interfaced data collection systems has made scanning wavelength kinetics experiments practical for times as short as the stopped flow time scale (1)(2)(3)(4)(5)(6)-In a typical scanning wavelength kinetics experiment, a spectral region is rapidly and repeatedly scanned while a spectrophotometric response such as absorbance, fluorescence, or chemiluminescence is measured at a fixed number of wavelength channels across the spectrum during each scan. If the time duration of each scan is short compared to the fastest spectrophotometrically detectable process in the reaction, the data can be regarded as a series of N consecutive, instantaneous spectra measured at p wavelength channels and can be represented by a (p X N ) matrix A, where A,j is the spectrophotometric response measured at wavelength channel i at the time of scan j .…”

mentioning

confidence: 99%

Statistically weighted principal component analysis of rapid scanning wavelength kinetics experiments

Cochran¹,

Horne²

1977

Anal. Chem.

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Prlnclpal component analysls Is used to develop a procedure for determlnlng the number of linearly Independent specles absorbing, fluorescing, or emitting llght In rapld scannlng wavelength klnetlcs experlments. The prlnclpal components of the data-second moment matrlx ghre for the specles nunber a lower estimate that Is sensltlve to the llnear dependence of the specles concentratlons; the prlnclpal components of the data-sample covarlance matrlx give a lower estimate that Is sensltlve to the llnear dependence of the tlme rates of change of the specles concentrations. An example Illustrates that the varlatlon of the experimental slgnal-to-noise ratlo wlth wavelength and tlme leads to Incorrect estlmates of the number of reactlng species. Thls error Is eliminated by statistically welghtlng the prlnclpal component calculatlons accordlng to a general model of error varlances.The development of sophisticated computer interfaced data collection systems has made scanning wavelength kinetics experiments practical for times as short as the stopped flow time scale (1-6)-In a typical scanning wavelength kinetics experiment, a spectral region is rapidly and repeatedly scanned while a spectrophotometric response such as absorbance, fluorescence, or chemiluminescence is measured at a fixed number of wavelength channels across the spectrum during each scan. If the time duration of each scan is short compared to the fastest spectrophotometrically detectable process in the reaction, the data can be regarded as a series of N consecutive, instantaneous spectra measured at p wavelength channels and can be represented by a (p X N ) matrix A, where A,j is the spectrophotometric response measured at wavelength channel i at the time of scan j .The reason for sampling this three-dimensional space of response-wavelength-time instead of the simpler two-dimensional space obtained in a fixed wavelength experiment is the need to characterize kinetic systems that contain more than one absorbing, fluorescing, or chemiluminescent solute. Whether the ultimate goal is to assay simultaneously several such solutes in a kinetic system with a known rate law, or to propose and test mechanisms for a complex reaction such as an enzyme system with detectable substrates, products, enzymes, and enzyme-bound intermediates, a necessary first step in data analysis is to determine how many detectable solutes occur in the reaction. The multivariate statistical method of principal component analysis, which has been applied to spectral studies of multicomponent equilibrium systems (7-IO), band resolution of IR spectra ( I I ) , analysis of potentiometric data ( E ) , and analysis of mass spectra (13, I4), is ideally suited for determining the number of detectable solutes in rapid scanning wavelength kinetics experiments.The analogy between spectral studies of multicomponent equilibrium systems and scanning wavelength kinetics experiments and the applicability of principal component analysis to both was pointed out and demonstrated by Sylvestre, Lawton, and Maggio...

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“…When the beam has passed, the capacitors discharge a t a rate determined by the value of the series resistance, which decreases with increasing light intensity. The next sweep of the electron beam restores the charge lost from the capacitor and an amplifier responds to the charging current which is proportional to the integrated light intensity between sweeps (26,27). The total active area of the vidicon used was 12.7 by 10.2 mm.…”

Section: Optical Systemmentioning

confidence: 99%

Imaging detector for mass spectrometry

Beynon¹,

Jones²,

Cooks³

1975

Anal. Chem.

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An imaging ion detector, consisting of an array of channel electron multipliers, a phosphor, an optical system, a vidicon camera, and a data acquisition unit, has been fitted to a Mattauch-Herzog mass spectrometer. The detector repiaces the conventional photographic plate in such instruments and has far greater sensitivity, although, in its present form, it gives lower resolution. its use in simultaneous multiple ion monitoring Is demonstrated and its application in ion kinetic energy spectrometry is foreseen. Deiiterious effects of fringing magnetic fields on the resolution of the device and saturation effects in the channeitron are discussed. The feasibility of achieving the enhanced sensitivity inherent in imaging detection in mass spectrometry is established.The photographic plate has played an important part in the practice of mass spectrometry since the earliest days. Specially prepared plates were used by Thomson (I, 2 ) in the detection system of the parabola spectrograph and similar plates are still used today on high resolution instruments (3-5) in which the arrangement of electric and magnetic fields used produces a plane of focus, as in the Mattauch-Herzog geometry (6). On the other hand, the electrical detection system used on other high and low resolution mass spectrometers has been continuously developed with respect to both its sensitivity and accuracy since the time when currents were detected using gold leaf electroscopes.

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Evaluation of a vidicon scanning spectrometer for ultraviolet molecular absorption spectrometry

Cited by 55 publications

References 9 publications

Derivative spectrometry with a vidicon detector

Derivative spectrometry with a vidicon detector

Statistically weighted principal component analysis of rapid scanning wavelength kinetics experiments

Imaging detector for mass spectrometry

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