Non-linearity effects in optical scanning of chromatograms

✍ Scribed by Victor Pollak; Alan A. Boulton

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 704 KB
• Volume: 50
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)97913-5

✦ Synopsis

The present paper is concerned with the error due to a finite spatial or spectral width of the illuminating scanning window in photodensitometers and reflectometers. The optical transfer characteristic of the medium is approximated by an exponential dependence tipon the increment in absorbance, which produces the largest error. The results obtained are therefore worst case estimates. It is shown, that the absolute error in this case is with good approximation proportional to the mean square deviation of the absorbance from its mean value taken over the window. The more important percentage errors increase with increasing relative non-uniformity, that is with increasing ratio of variance to mean value. The results obtained are illustrated in three fairly typical numerical examples; the last of these showing that contrary to general practice relatively wide spectral windows may be tolerated without excessive error.