Buffer radiation

To suppress the ionization of a metal, another easily ionized metal (denoted a deionizer or radiation buffer) is added to the sample. To ensure that ionization is suppressed for the test element, the product of the deionizer must exceed the similar product for the test element one hun-... 

Hi) Radiation buffer for sodium determination Prepare a saturated solution with reagent-grade CaCl2, KC1, MgCl2, in that order. 

Radiation buffers are used to minimise the effect of each ion upon the emission intensity of the others. 

If the source of interference is known, an excess of the interfering substance may be added to the sample as well as the standards provided the excess is sufficient enough with respect to the concentration from the sample matrix, the concentration of the latter will thus become insignificant. Such an added substance is sometimes referred to as a radiation buffer. 

Flame atomic absorption is subject to many of the same chemical and physical interferences as flame atomic emission (see Section 28C-2). Spectral interferences by elements that absorb at the analyte wavelength are rare in AA. Molecular constituents and radiation scattering can cause interferences, however. These are often corrected by the background correction. schemes discussed in Seetion 28D-2. In some cases, if the source of interference is known, an excess of the interferent can be added to both the sample and the standards. The added substance is sometimes called a radiation buffer. 

A radiation buffer is a substance that is added in large excess to both samples and standards to swamp out the effect of matrix species and thus to minimize interference. 

Radiation buffers Potential interferents that are intentionally added in large amounts to samples and standards to swamp out their effects on atomic emission measurements. 

Fig. 3. Scheme of an optical fiber. The acceptance cone is determined by the critical angle for incoming light radiation. Buffer absorbs the radiation not reflected by the cladding. Jacket has a protective function. 

Isolation of radioactive wastes for long periods to allow adequate decay is sought by the use of multiple barriers. These include the waste form itself, the primary containers made of resistant materials, overpacks as secondary layers, buffer materials, concrete vaults, and finally the host rock or sod. Barriers limit water access to the waste and minimize contamination of water suppHes. The length of time wastes must remain secure is dependent on the regulatory limit of the maximum radiation exposure of individuals in the vicinity of the disposal site. 

For maintenanee of optimum values pH at definition of Rh and Ir used the aeetie buffer mixes, prepared with addition of isopropanole. Colour of eomplexes develops within 2 h at 65 5°C or during 5 min under influenee of mierowave radiation. 

It is sometimes possible to improve detection by changing the pH of the eluent, or by the use of photochemical reactions. The common barbiturates used in therapy are weak acids that are easily separated in their acid (unionised) forms. Because the conjugate bases are much stronger chromophores than the acids, barbiturates have been detected by post-column mixing with a pH 10 borate buffer followed by uv absorption at 254 nm. An example of the second approach is the detection of cannabis derivatives in body fluids involving the conversion of cannabis alcohols to fluorescent derivatives on subjecting the column effluent to intense uv radiation. 

Kreuter and Speiser [77] developed a dispersion polymerization producing adjuvant nanospheres of polymethylmethacrylate) (PMMA). The monomer is dissolved in phosphate buffered saline and initiated by gamma radiation in the presence and absence of influenza virions. These systems showed enhanced adjuvant effect over aluminum hydroxide and prolonged antibody response. PMMA particles could be distinguished by TEM studies and the particle size was reported elsewhere to be 130 nm by photon correlation spectroscopy [75], The particle size could be reduced, producing monodisperse particles by inclusion of protective colloids, such as proteins or casein [40], Poly(methylmethacrylate) nanoparticles are also prepared... 

Also noted in Figure 7A are three small ion mobility peaks at drift times of about 28,30 and 33 ms. These unwanted ions are formed in the ion source by the clustering of the Cr ion to HCl, HCOOH, and CHjCOOH. These impurities are not introduced with the buffer gas, but are formed by the Ni-induced radiation chemistry that is continuously occurring in the ion source. Because these ions do not interfere with the IM reaction of interest in Figure 7, their presence can be ignored as long as their... 

Reaction at 85 °C of Fe " sulphate solution (buffered at pH 6 with sodium acetate) with hydroxylamine salts. The reaction is carried out under N2 and within 2 h, large clumps of acicular goethite, radiating from a central point, are formed (Ardizzone and Formaro, 1985). 

Takakura, K. Ishikawa, M. Ito, T. Action spectrum for the induction of single-strand breaks in DNA in buffered aqueous solution in the wavelength range from 150 to 272 nm dual mechanism. Int. J. Radiat. Biol. 1987, 52 (5), 667-675. 

Takakura, K. Maezawa, H. Kobayashi, K. Hieda, K. Strand breaks in DNA in buffered solution induced by monochromatic X-rays around the K-shell absorption edge of phosphorus. In Synchrotron Radiation in Biosciences. Chance, B., Deisenhofer, J., Ebashi, S., Goodhead, D.T., Helliwell, J.R., Huxley, H.E., lizuka, T., Kirz, J., Mitsui, T., Rubenstein, E., Sakabe, N., Schmahl, G., Stuhrmann, H.B., Wuthrich, K., Zaccai, G., Eds. Oxford University Press Oxford, 1994 756-764 pp. 

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