Impulse response photoacoustic spectroscopy has been used to study variations in chromophore distribution with time in a dynamic system. A system in which a dye diffuses through a polymer film has been examined, and it is shown that it is possible to monitor the diffusion process in situand non-destructively. Comparison of the experimental results with a theoretical model demonstrates that the results are consistent with classical diffusion processes.
The use of impulse-response photoacoustic signals to monitor time-dependent changes in physicochemical systems is described. The diffusion of a dye through a polymer and the effect of a herbicide on a plant leaf are used to demonstrate the viability of the technique.On decrit l'utilisation des signaux photo-acoustiques de reponse aux impulsions pour suivre les changements dependant du temps dans des systbmes physico-chimiques. On utilise la diffusion d'un colorant a travers un polymbre et I'effet d'un herbicide sur la feuille d'une plante pour demontrer la viabiliti de cette technique. Can. J. Phys. 64. 1146 (1986 [Traduit par la revue]
A commercially available hydride generator, with a novel
membrane gas-liquid separator, has been coupled to a new ICPMS
instrument which itself features many unique design
considerations. Little or no optimization of the mass spectrometer or
ionization source was required to obtain excellent analytical data;
and a variety of matrices have been analysed.
The elements As and Se are usually used to demonstrate the
effectiveness of a hydride generation system, and these are of
particular importance, bearing in mind potential Ar molecular
overlaps with isotopes of interest. The flexibility of the hydride
generation ICP-MS system is highlighted, with the inclusion of
analytical figures of merit for the elements Sn, Sb, Ge and Hg, as
well as As and Se. Data obtained by ‘standard’ pneumatic
nebulization on the ICP-MS is compared with that obtained with
the hydride generator for all of the elements.
Improvements of between 50 and 100 times were gained in
measurements of three sigma detection limits for all elements in the
determinations, including Hg. Measurements were made on several
isotopes for particular elements, and the data is included for the
purposes of comparison. Stabilities of between 1 and 2.5% were
obtained for 0.5 ppb solutions over 10 min measurement periods, all
data is presented without using an internal standard.
Finally, analytical data from seawater standards, spiked with low
levels of As and Se and calibrated against aqueous standards,
demonstrate excellent recoveries. This is of particular interest
bearing in mind the well-documented molecular interferences from
high chloride matrices on As and Se analysis.
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