Hydrochloride-nitric acid reagent

Sample Treatments. Blood (1 ml) and fecal samples (1 g dry-matter) were ashed on hot plates by sequential treatment with concentrated nitric acid and 30% hydrogen peroxide. The white residue of each sample was dissolved in 3-5 ml of 6 N HCl, and the final volume was brought up to 25 ml with 6 N HCl. Several 0.1 ml aliquots were transferred to test tubes, and iron concentrations were determined by a colorimetric method using the Batho-reagent (17) which contains hydroxylamine hydrochloride (10%), sodium acetate (1.5 M), and bathophenan-throline disulfonate (0.5 mM). The analytical precision of iron quantification was evaluated by measuring the iron concentrations of 13 replicates of one imenriched fecal sample. The mean of these measurements was 365.7 ug per gram of dry feces, with a relative standard deviation of 2. 8%. 

Hydroxylamine hydrochloride, dissolved in acetic or nitric acid, was shown to selectively extract Mn oxyhydroxides and Mn oxides, as well as amorphous Fe oxides (Chester and Hughes, 1967 Chao, 1972 Chao and Zhou, 1983). This reagent was used for the extraction of trace metals associated with hydrous oxides of Fe and Mn in soils (Gupta and Chen, 1975 Stover et al, 1976 Tessier et al, 1979 Harrison et al, 1981 Miller and McFee, 1983 Miller et al, 1986a, b Rule and Alden, 1992 Krishnamurti et al, 1995a Krishnamurti and Naidu,... 

In a procedure for the analysis of radioiodine In vegetation (ref. 376, pp. 94ff), the following reagents were added to the sample carrier copper foil cerlum(IV) sulfate sulfuric acid and potassium permanganate. The mixture was heated until the sample was completely oxidized. Then oxalic acid was added to convert the Iodine to the elemental form and the iodine was distilled Into aqueous sodium hydroxide. The alkaline solution was treated with hydroxylamlne hydrochloride, sodium nitrite, and nitric acid and the free Iodine was extracted Into carbon tetrachloride. The Iodine was back-extracted as Iodide with sul-furous acid and precipitated as the silver salt. 

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