Nitric acid simultaneous determination with

The parts-per-billion level of metal ions in 500 ml of the mobile phase was continuously concentrated into small volumes of the stationary phase retained in the column. Concentrated metal ions were simultaneously eluted with nitric acid and determined by the emission intensity with a DCP-AES. The recoveries of Ca, Cd, Mg, Mn, Pb, and Zn... 

Harly extractions of pertechnetate, dissolved in 1 N H2SO4, with a 0.1 M solution of tri-/(-octylamine (TOA) in cyclohexane resulted in distribution coefficients of Dic= 110 at 25 °C jl 11]. Recently, Dy was determined as a function of the nitric acid concentration using 0.01 and 0.1 M solutions of tri- -octylamine in benzene. The distribution coefficients increased with increasing acidity until a maximum was reached near 0.1 M 11N03. At higher concentrations of nitric acid, D y. fell rapidly because of competition from the simultaneously extracted nitric acid, which reduces the concentration of free tri-n-octylamine available to extract TcO (Fig. 7.8.A). llic extraction is considerably affected by the temperature. A linear relation is obtained between D y. and the concentration of TOA. The slope of 1.0 indicates an extractant Tc ratio of 1 1. The extraction of pertechnetate from aqueous HKO3 solution may be represented by the equation [ 117] ... 

Take 50 ml of the water sample either as such or concentrated or diluted, and treat with 10 - 20 ml of cone, sulphuric acid (or 2 - 3 ml of cone, sulphuric acid, 5 ml of cone, nitric acid + 0.5 ml of 30 % H2O2), reducing the sample in a quartz dish until sulphur trioxide vapour appears. It is advisable to conduct simultaneous parallel determinations and in addition to add a known quantity of arsenic to a measured volume of water and to... 

Figure 3.7 shows an FIA system for the determination of metals using a column packed with a chelating solid phase (ChelexlOO). Initially, the loop of valve 1 is loaded with an appropriate volume of sample that is then injected into the manifold in order to have metals retained on the chelating column. Simultaneously, the loop of valve 2 is loaded with nitric acid of an appropriate concentration. As the acid is injected onto the column, it protonates the iminodiacetic groups and releases the metals, which are then driven to the detector (e.g. an atomic absorption spectrophotometer). 

FIGURE 2 The influence of authentic nitric oxide (-NO) infusion on xanthine oxidase (XO)-dependent liposome oxidation. PC liposomes (6.6 mg/ml) were oxidized with 1.5 mil/ ml XO, 10 mM acetaldehyde, and 100 /aM EDTA-Fe. Infusion of -NO (0.1, 0.25, 0.5, 0.7, 1, 2, and 3 /uM/min) was performed simultaneously. The open circle represents incubation of the reaction mixture in the absence of XO. The data represent the mean of duplicate determinations and were representative of three separate experiments. TBA, 2-Thiobarbituric acid. [Adapted from Rubbo et al. (1994a) with permission.]... 

Metallic elements are present in air mostly as particulate material, which can be removed inter alia by filtration. Dusts are simply air particulates that have collected naturally by gravitation. Atomic spectrometry methods are well adapted to the analysis of used air filters. For instance, filters of the cellulose acetate type can conveniently be destroyed by oxidation with nitric/perchloric acid while the metallic elements are thereby solubilized. The resulting aqueous solution, of small volume, can be analysed simultaneously for many elements by ICPAES or ICPMS. The former is quite capable of determining most elements at their threshold concentration after the filtration of (say) 10 litres of air. Alternatively, air filters have a suitable form for direct analysis by XRF in special filter holders. 

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