Single optical fiber, position-sensitive detector-based multiwavelength absorbance spectrophotometer

Journal Article · Thu Mar 15 00:00:00 EST 1990 · Analytical Chemistry (Washington); (USA)

DOI:https://doi.org/10.1021/ac00205a005· OSTI ID:6279543

Renn, C N; Synovec, R E ^[1]

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1. Univ. of Washington, Seattle (USA)

A relatively simple, yet stable and versatile, multiwavelength absorbance spectrophotometer is described. A broad-band mercury-xenon source was coupled into a single UV-vis transmitting optical fiber, through a detection cell, and dispersed by a monochromator onto the face of a continuous position-sensitive detector (PSD). Two wavelength regions illuminated opposite ends of the PSD while the remainder of the dispersed light was masked. Photocurrent contributions by the two wavelength regions were readily balanced to achieve a stable electronic null condition. The resulting optical configuration provided absorbance measurements simultaneously at two wavelengths, while also correcting for light source intensity fluctuations and refractive index aberrations. The absorbance detector was applied in microbore liquid chromatography with a 6 mm path length z-configuration flow cell (1.2 {mu}L volume). A 1.1 {times} 10{sup {minus}4} au (3 {times} root mean square noise level, 60-s intervals) was routinely achieved, which constitutes over a factor of 10 reduction in noise due to light source fluctuations. Aldehyde derivatives with 2,4-dinitrophenylhyrazine were chromatographically analyzed as a test system. The mass detection limit of injected formaldehyde was 4 pg. The new detection system should be advantageous in remote-sensing applications, including flow injection analysis, high-temperature liquid chromatography, biological monitoring, and environmental monitoring.

• OSTI ID: 6279543
• Journal Information: Analytical Chemistry (Washington); (USA), Vol. 62:6; ISSN 0003-2700
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
47 OTHER INSTRUMENTATION
SPECTROPHOTOMETERS
DESIGN
ABSORPTION SPECTROSCOPY
MEASURING METHODS
OPTICAL FIBERS
POSITION SENSITIVE DETECTORS
FIBERS
MEASURING INSTRUMENTS
RADIATION DETECTORS
SPECTROSCOPY
400102* - Chemical & Spectral Procedures
440600 - Optical Instrumentation- (1990-)