Nitric acid digestion

Earlier work on the determination of total mercury in river sediments also include that of Iskander et al. [41], Iskander applied flameless atomic absorption to a sulphuric acid nitric acid digest of the sample following reduction with potassium permanganate, potassium persulphate and stannous chloride. A detection limit of one part in 109 is claimed for this somewhat laborious method. 

The <0.063 mm fraction of till was analyzed by aqua regia and lithium metaborate fusion-nitric acid digestions ICP/ES and MS. 

A separation procedure was developed after a simplex optimisation of a nitric acid digestion to determine lanthanides and yttrium in rare earth ores and concentrates... 

Mortatti et al. [16] has described a method for the determination of total iron in extracts of perchloric acid-nitric acid digests of plant materials. Their method involves flow injection analysis of the 1 10 phenanthroline complex. 

Acidify with nitric acid, digest if necessary... 

An older Be method, P CAM 121, discusses air, dust, ore, and swipe samples. More vigorous digestion procedures such as hydrofluoric nitric acid for filters or potassium fluoride sodium pyrosulfate fusion and nitric acid digestion for ores. A nitrous oxide/acetylene flame is suggested for this method rarely used (Table HI). 

Molybdenum. Molybdenum can be analyzed by P CAM 173 for total Mo, by S-193 (12) for soluble Mo, or by S-376 for insoluble Mo. The standard nitric wet ashing used in P CAM 173 does not distinghish between soluble and insoluble Mo which have OSHA standards of 5 mg/cu m and 15 mg/cu m. Nitric acid digestion may not dissolve some insoluble Mo that require nitric/perchloric acid or base/nitric acid depending on the solubility properties. Soluble Mo compounds are hot water leached from the cellulose membrane filter used in all three methods. A fuel-rich air/acetylene flame used in P CAM 173 is replaced by an oxidizing nitrous oxide/acetylene flame to achieve total atomization of Mo as detected at 313.3 nm. Aluminum and traces of acid enhance the Mo flame response therefore, 400 ppm A1 is added to the final solution of both S-193 and S-376 and 0.1 N nitric acid is added to the water leach-soluble Mo final solution, S-193. 

Oliver [190] recommends the dissolution of the polymer if possible (see above) but in other cases a wet ashing procedure was used. The sample was heated with 2—3 ml of concentrated sulphuric acid and then hydrogen peroxide added drop-wise until the organic matter was destroyed. Twenty elements were determined in a 2% solution of polymer. Polymers may be dispersed in an organic solvent and trace metals removed by leaching with an appropriate aqueous solution, preferably the procedure should be repeated more than once to ensure complete extraction. To determine antimony in fire-retardant polypropylene, the sample was dispersed in xylene and extracted with 6M hydrochloric acid under reflux [191]. The filtered acid layer was combined with two further extracts prior to aspiration into the air/acetylene flame and measurement at 217.6 nm. Martinie and Schilt [45] reported that nylon would dissolve completely in perchloric/nitric acid digestion but potentially explosive problems were encountered in the dissolution of Amberlite resins and rubber. 

Amaarsiriwardena, D., Krushevska, A., Bames, R.M. Microwave-assisted vapor-phase nitric acid digestion of small biological samples for inductively coupled plasma spectrometry. Appl. Spectrosc. 52, 900-907 (1998)... 

Most water samples do not require pre-treatment for total elemental analysis, but where organic arsenic or selenium compounds are suspected, pretreatment by digestion with a strong acid mixture, for example, a 3 min sulfuric acid-potassium persulfate digestion or a nitric acid digestion, is necessary. Where pre-concentration is required, cold trapping of the hydrides or liquid-solid extraction has been used but this is very labor intensive when performed offline. 

Tuckerman and collaborators state that chloric acid is to be preferred to the more widely used sulphuric acid or sulphuric-nitric acid digestions or alkaline fusions recommended for the determination of arsenic in organic compounds. Excess chloric acid is easily removed by boiling to leave a perchloric acid solution of inorganic As(V). Rapid micro and semi-micro methods for the determination of arsenic based on chloric acid digestion are described. 

Similar inconsistencies have been encountered in the determination of other elements such as selenium [125,133], arsenic [118,130], copper [119,123] and zinc [120,122]. On the other hand, methods for the determination of mercury are slightly more consistent, with many workers using a closed-vessel nitric acid digestion procedure. Good results have thus been obtained with pig kidney [124,141], mussel tissue [138], cod muscle [137], citrus leaves [136], pine needles [136], albacore tuna [131] and fish tissue [124], among others. 

Wastes/soil/ groundwater Nitric acid digestion or nitric/peroxide/hydrochloric acid digestion AA, furnace 3x1 O 9 g/mL 100.5% EPA 1997b (method 7742)... 

Figure 1 Anion- and cation-exchange chromatograms of nitric acid digests of NRCC DORM 2 heated to different temperatures. An HP4500 inductively coupled plasma mass spectrometer was used as element-specific detector.

Lead in nitric acid digests of hair has been accurately measured by flame atomic spectrophotometry (S6). Renshaw et al. (R3) used nonflame atomic absorption to measure lead in single sections of hair. 

The decomposition of bastnaesite has been intensively investigated. At the U.S. Bureau of Mines at the end of the 1950s, two processes were developed. One involved nitric-acid digestion and solvent extraction, the other involved sulphuric acid and recovery of the rare earths as water soluble sulphates (Gupta and Krishnamurthy 2005). 

Both nitric acid digestion and enzyme digestion were tested with liver and lung tissue as well as with cultured cells. Tissue processing with a mixture ofi protease enzymes is preferred because it is applicable to a wide range of particle compositions. Samples were visualized via fluorescence microscopy and transmission electron microscopy to validate the SdFFF results. We describe in detail the tissue preparation procedures and discuss method sensitivity compared to reported levels of nanoparticles in vivo. 

Zarcinas BA, Cartwright B, Spounser LR (1987) Nitric acid digestion and multi-element analysis of plant material by inductively coupled plasma spectrometry. Conunon Soil Sci Plant Anal 18 131-146... 

Figure 10.60 Separation of alkali metals, alkaline-earth metals, and ammonium in a sewage sludge after nitric acid digest. Separator column Metrosep Cation 1-2 eluent 4 mmol/L tartaric acid -H1 mmol/L pyridine-2,6-dicarboxylic acid flow rate 1 mL/min detection nonsuppressed conductivity injection...

Fig. 9-30. Separation of alkali metals, alkaline-earth metals and ammonium in a sewage sludge after nitric acid digest. - Separator column Metrosep Cation 1-2 eluant 4 mmol/L tartaric acid + 1 mmol/L pyridine-2,6-dicarboxylic acid flow rate 1 mL/min detection non-suppressed conductivity injection 10pL sample (1 25 diluted) solute concentrations 0.22 mg/L lithium (1), 26 mg/L sodium (2), 4.9 mg/L ammonium (3), 5.8 mg/L manganese (4), 210 mg/L potassium (5).

Ziegler, D. and Readnour, M., Comparison of the persulphate and sulphuric acid-nitric acid digestion for analysis of phosphorus in water. Transactions of the Missouri Academy of Science 9, 144,1975. 

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