Slurry atomic spectroscopy

The number of applications of atomic techniques based on solid or slurry sampling is so large that only a comparatively minute fraction is discussed in this section. Interested readers are referred to the biannual reviews of Analytical Chemistry and the atomic spectroscopy update in the Journal of Analytical Atomic Spectrometry, among other sources, for more extensive information. A specific review of the uses of graphite atomizers modified with high-melting carbides has been published by Volynsky that includes virtually all metals determined in this manner [74]. 

For the first five atomization sources listed in Tabic 8-1, samples are usually introduced in the form of aqueous solutions (occasionally, nonaqueous solutions are used) or less often as slurries (a slurry is a suspension of a finely divided powder in a liquid). For samples that are difficult to dissolve, however, several mcth(xls have been used to introduce samples into the atomizer in the form of solids or finely dispersed powders. Generally, -solid sample-introduction techniques are less reproducible and more subject to various errors and as a result are not nearly as widely applied as aqueous solution techniques. Table 8-2 lists the common sample-introduction methods for atomic spectroscopy and the type of samples to which each method is applicable. 

E.J. dos Santos, A.B. Herrmann, M.A. Vieira, V.L.A. Frescura, and A.J. Curtius. Evaluation of slurry preparation procedures for the determination of mercury by axial view inductively coupled plasma optical emission spectrometiy using on-line cold vajror generation. Spectrochimica Acta Part B Atomic Spectroscopy 60 659-665, 2005. 

Before bismuth-promotion the Pt-on-alumina catalyst was pre-reduced in water with hydrogen. The pH was decreased to 3 with acetic acid and the appropriate amount of bismuth nitrate dissolved in water (10 - lO " M) was added into the mixed slurry in 15-20 min, in a hydrogen atmosphere. Promotion of unsupported Pt was carried out similarly. The metal composition of the bimetallic catalysts was determined by atomic absorption spectroscopy. 

The most common analytical procedures for measuring cadmium concentrations in biological samples use the methods of atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES). Methods of AAS commonly used for cadmium measurement are flame atomic absorption spectroscopy (FAAS) and graphite furnace (or electrothermal) atomic absorption spectroscopy (GFAAS or ETAAS). A method for the direct determination of cadmium in solid biological matrices by slurry sampling ETAAS has been described (Taylor et al., 2000). 

The MgO samples were heated under vacuum to 500 °C before use. Mn(acac) -NAP-MgO was prepared by treating vacuum dried NAP-MgO (1.0 g) with Mn(acac)3 (0.20 g) in THF (8.0 mL) under a nitrogen atmosphere at room temperature and stirring for 24 h by a method similar to that reported by Klabunde and co-workers. The slurry was filtered off, washed with THF, and vacuum dried to give Mn(acac) -NAP-MgO (1.105 g, brownish color). The I R spectrum shows evidence for the incorporation of the Mn(acac) moiety. The Mn content in Mn(acac) -NAP-MgO was determined to be 0.369 mmol g by atomic absorption spectroscopy (AAS). 

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