A simple backing off system for kinetic spectrophotometry

Wilkinson, Frank; Ellison, D.H.

doi:10.1016/0020-7055(73)90014-4

Cited by 3 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…recording the oscilloscope display of light absorption against time for perhaps 10-30 individual wavelengths over the range of interest. Most circuits present the data in the form of changes of light absorption induced by the radiation pulse, 'backing-off' the initial optical density of the solution to record a zero or baseline absorption immediately before the radiation pulse (Keene andBell 1973, Wilkinson andEllison 1973). This is illustrated in figure 6 to the concentration c (mol dm-3) of species with extinction coefficient E (dm3 mol-1 cm-1) in a cell with path length I (cm):…”

Section: Optical Detection Of Transientsmentioning

confidence: 99%

Application of pulse radiolysis methods to study the reactions and structure of biomolecules

Wardman

1978

Rep. Prog. Phys.

View full text Add to dashboard Cite

T o study reactions occurring on timescales faster than N 10-&lo-3 s, simple mixing of reagents is too slow and other methods of initiating reactions have to be used. Pulses of thermal energy, light quanta or ionising radiation have been used to perturb chemical and biological systems from equilibrium. Pulse radiolysis is the more recent of these three methods of initiating fast reactions, and this review emphasises the versatility of this technique for studying events occurring between 10-11 and 1 0 2 s after energy absorption. The extent and tiniescale of radiation damage in dilute aqueous solutions are outlined and the facile manipulation of experimental conditions to isolate a single reactive species is illustrated. The basic requirements for the radiation pulse and detection system are discussed. T h e experimental techniques which have been used to monitor fast reactions following pulse radiolysis include optical absorption spectroscopy and light scattering, and timeresolved electrical conductivity, polarography, and electron spin resonance spectroscopy. Some applications of pulse radiolysis to study fast reactions of biologically important molecules are illustrated, including the kinetics and thermodynamics of redox processes and electron-transfer reactions, enzymic processes and structural effects which are revealed by physical or kinetic properties.

show abstract

Section: Optical Detection Of Transientsmentioning

confidence: 99%

Application of pulse radiolysis methods to study the reactions and structure of biomolecules

Wardman

1978

Rep. Prog. Phys.

View full text Add to dashboard Cite

show abstract

Electronic analyzing light signal subtraction and measuring device for transient absorption spectrophotometry

Luthjens¹,

Hom²,

Vermeulen³

1984

Review of Scientific Instruments

View full text Add to dashboard Cite

High intensity pulsed analyzing light sources for nano and microsecond absorption spectrophotometry Rev.An electronic system is described that subtracts the analyzing light signal level from the analyzing light signal modulated by a transient absorption signal at the output of a photodetector in a transient absorption spectrophotometer. The system enables sensitive measurement of the transient with simultaneous measurement of the analyzing light level immediately before the transient. The shortest rise time is 50 ns. The time window for the measurement can be selected to a maximum of20 ms with a droop of20f.-lV. Input signals of 10 V of either polarity are permitted. The minimum detectable absorption signal is determined by the noise of the photomultiplier used and can be about 0.2% for an experiment without signal averaging. PACS numbers: 07.65. -b, 07.60.Dq 495 Rev. Sci.lnstrum. 55 (4), April 1984

show abstract

A Pulse Radiolysis Study of Zinc(II)—insulin

Elliot

Wilkinson²,

1980

International Journal of Radiation Biology and Related Studies

View full text Add to dashboard Cite

Reactions of eaq with zinc(II)-insulin at pH 6.6 and 9.0 yielded relatively low disulphide anion absorptions, suggesting eaq reacts at other sites than S-S. A similar conclusion was reached for the reation of CO2 where an even lower yield of disulphide anion was found. However, here the disulphide anion yield increased with 'prepulsing'. Simultaneously the rate constant decreased, implying that a more reactive site was 'cleaned up'. While no reaction of Br2 with insulin was observed, both OH and Cl2 reacted rapidly and predominantly at the tyrosine residues. The second order rate constants, calculated in terms of insulin monomer concentrations, are reported for eaq, CO2 and Cl2. The transient spectra qualitatively support evidence regarding the accessibility of S-S bonds and tryosine residues in the various forms of insulin as predicted from earlier studies.

show abstract

A simple backing off system for kinetic spectrophotometry

Cited by 3 publications

References 1 publication

Application of pulse radiolysis methods to study the reactions and structure of biomolecules

Application of pulse radiolysis methods to study the reactions and structure of biomolecules

Electronic analyzing light signal subtraction and measuring device for transient absorption spectrophotometry

A Pulse Radiolysis Study of Zinc(II)—insulin

Contact Info

Product

Resources

About