Absorption ionization effects

Atomic absorption spectroscopy is highly specific and there are very few cases of interference due to the similar emission lines from different elements. General interference effects, such as anionic and matrix effects, are very similar to those described under flame emission photometry and generally result in reduced absorbance values being recorded. Similarly, the use of high temperature flames may result in reduced absorbance values due to ionization effects. However, ionization of a test element can often be minimized by incorporating an excess of an ionizable metal, e.g. potassium or caesium, in both the standards and samples. This will suppress the ionization of the test element and in effect increase the number of test atoms in the flame. 

Chapman, S., The absorption and dissociative or ionizing effect of monochromatic radiations in an atmosphere on a rotating earth. Proc Phys Soc 43, 483, 1931. 

Looking for functional group balance water solubility and absorption ionization issues effect on solubility and absorption Drug combinations acid-base interactions Drug interactions with biological target good fit or not ... 

A consequence of absorption of X rays is the inner shell ionization of the absorbing atoms and the subsequent generation of characteristic X rays from the absorbing atoms, called secondary fluorescence, which raises the generated intensity over that produced by the direct action of the beam electrons. Secondary fluorescence can be induced by both characteristic and bremsstrahlung X rays. Both effects are compo-sitionally dependent. 

A similar effect can be observed in anthaquinones, mainly for the presence of an hydroxyl group. The ionization of hydroxyl groups under basic conditions also undergoes a bathochromic shift. Alizarin has two absorption bands in the vis region, simated at 567 and 609 nm carminic acid has a visible absorption maximum at around 500 nm and kermesic acid at 498 mn. 

Tam et al. [37-47] developed an impressive generalized method for the determination of ionization constants and molar absorptivity curves of individual species, using diode-array UV spectrophotometry, coupled to an automated pH titrator. Species selection was effected by target factor analysis. Multiprotic compounds with overlapping pK s have been investigated binary mixtures of ionizable compounds have been considered assessment of inicroconstants have been reported. 

Genetic Effect of Radiation—Inheritable change, chiefly mutations, produced by the absorption of ionizing radiation by germ cells. Genetic effects have not been observed in any human population exposed at any dose level. 

As indicated, the ionized form of a drug will be more soluble than the nonionized form in the aqueous fluids of the GIT. The classic studies on the beneficial effects of changing nonionized drugs into salt forms were reported by Nelson for tetracycline [25], and Nelson et al. for tolbutamide [26]. Table 2 combines portions of the data from each study. Urinary excretion of the drug or its metabolite was taken as the in vivo measure of the relative absorption rate for the salt and the nonionized... 

For concentrated or bulk samples a transmission experiment is both the simplest and the most effective. In essence, one measures the X-ray intensities incident and transmitted through a thin and uniform film of the material. Careful analysis of signal-to-noise ratio considerations indicates that optimal results are obtained when the sample thickness is of the order of 2.5 absorption lengths. Since in this case a simple Beer s law applies, the data are usually plotted as In(7//0) versus E. The intensities are measured using ionization chambers in conjunction with high-gain electrometers (see Fig. 11). 

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