تسجيل الدخول

تسجيل

Instrument calibration , Data resolution

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  p430-431

2026-11-14

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Instrument calibration

Data resolution

In a computer, spectra are stored as lists of wavenumber and transmittance (absorbance) data pairs. These X,Y data pairs are plotted on demand. A sufficient number of data points are required to give an undistorted picture. Too many points may be unnecessary and require excessive memory allocations. Figure 1 illustrates the effects of spectral and data resolution on the spectral integrity of the IR spectrum of a 0.04 mm thick polystyrene film. The terms spectral resolution and data resolution are often confused. Some instruments, in modifying the Fourier transform mathematics to reduce the SBW, also produce a change in the data resolution of the spectra computed. The 1154 cm^-1 band of polystyrene is reproduced in Fig. 1 measured with different SBW and data resolution. Viewing the spectra presented in Fig. 1 indicates that data resolution can be a more important issue than spectral resolution. In general, for typical drug molecules, a SBW of 4cm^-1 is probably sufficient to describe faith fully the natural bandwidth of a vibrational absorption band. However, a data resolution of 1cm^-1 is preferred to ensure that the measured data are a faithful representation of the cap ability of the spectrometer. Increasing SBW, reducing data resolution, or both, can reduce noise.

Figure 1 Zoomed-in region of the IR spectrum of a 0.04 mm thick polystyrene film illustrating the effect of spectral bandwidth and data resolution.