The optical characteristics of on-capillary photometric detectors for capillary electrophoresis were evaluated and five commercial detectors were compared. Plots of sensitivity (absorbance/concentration) versus absorbance obtained with a suitable testing solution yield both the linear range and the effective path length of the detector. The detector linearity is a crucial parameter when using absorbing electrolytes, such as for indirect photometric detection, and especially for highly absorbing electrolyte probe ions. The upper limits of the linear ranges (determined as 5% decline in sensitivity) for five commercial detectors ranged from 0.175 to 1.2 AU. The effective pathlength reflects the quality of the optical design of the detector and is equal to the capillary internal diameter only for a light beam passing exactly through the capillary centre, but becomes progressively shorter for imperfect optical designs. The determined effective pathlength for the five investigated detectors ranged from 49.7 to 64.6 μm for a 75 μm I.D. capillary. © 2001 Elsevier Science B.V. All rights reserved.

Item Type:	Refereed Article
Research Division:	Chemical Sciences
Research Group:	Analytical Chemistry
Research Field:	Separation Science
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Chemical Sciences
Author:	Johns, CA (Dr Cameron Johns)
Author:	Macka, M (Professor Mirek Macka)
Author:	Haddad, PR (Professor Paul Haddad)
ID Code:	22203
Year Published:	2001
Web of Science® Times Cited:	21
Deposited By:	Chemistry
Deposited On:	2001-08-01
Last Modified:	2011-08-03
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