Digestion methods regia

The subsamples were split and sent to different laboratories to be subjected to ten commonly-used and proprietary leach/digestion techniques (a) aqua regia partial digestion method at Acme Analytical Laboratories (b) sodium pyrophosphate and cold hydroxylamine leaches at ALS Chemex (c) enzyme and TerraSol leach methods at Skyline Labs (d) Bioleach and soil gas hydrocarbon analyses at Activation Laboratories (e) Mobile metal ion (MMI) extraction at SGS Minerals (f) 4-acid near-total and sodium peroxide sinter total digestions (under the uses contract) at SGS Minerals and (g) de-ionized water leach at the USGS laboratories. 

For the certification of aqua-regia soluble trace element contents, it was mandatory that the participants follow strictly the same extraction procedure. The digestion method used was the DIN standard (German Norm 38414-S7) which is based on the digestion of 3 g material with HCl/HNO, following a detailed protocol that is described elsewhere [3,5]. 

Fig. 12.4a. Youden plot of the determination of Al in marine sediments expressed as z-scores. The plot shows clear systematic differences due to the method of sample digestion. The group of lower (left) results was obtained by digestion methods which did not include any HF treatment e.g. nitric acid or aqua regia. The upper (right) group used an HF treatment or non-destructive methods e.g. XRF.

The US EPA Method 3050B and its optional method (see Figures 5.2 and 5.3, respectively, above) were used, plus an aqua regia digest method (Figure 5.26). In each case, an accurately weighed 1.0000 g sample was used. 

Determination of palladium with dimethylglyoxime Discussion. This is one of the best methods for the determination of the element. Gold must be absent, for it precipitates as the metal even from cold solutions. The platinum metals do not, in general, interfere but moderate amounts of platinum may cause a little contamination of the precipitate, and with large amounts a second precipitation is desirable. The precipitate is decomposed by digestion on the water bath with a little aqua regia, and diluted with an equal volume of... 

Methods and Results At 15 sites along a 1000 m transect across the Talbot deposit, soil profiles were sampled in 10 cm depth intervals, up to 50 cm. The <250 pm (silt + clay) and <2pm (clay) fractions of the soil samples were analysed using an aqua regia digestion and ICP-MS measurement of 53 elements. 

Analytical Methods Whole rock and LA-ICPMS analyses were carried our at Universite du Quebec a Chicoutimi (UQAC). Sulfur was determined by combustion and IR analysis. Ni and Cu were determined by atomic absorption spectrophotometry after aqua regia digestion. Gold and PGE were determined by Ni-sulfide fire assay followed by Te co-precipitation followed by ICPMS. 

Elemental composition Ga 69.24%, P 30.76%. Gallium phosphide may be characterized hy its physical and electronic properties. It may also he analyzed hy various x-ray methods. Gallium may he measured hy AA and ICP spectrophotometry following digestion with nitric acid or aqua regia and appropriate dilution (See Gallium). 

Elemental composition Au 77.56%, F 22.44%. Gold(lll) fluoride may be characterized by x-ray techniques. The concentration of gold may be determined by AA and other instrumental methods following digestion in aqua regia and appropriate dilution. 

Elemental composition Hf 84.80%, O 15.20%. Hafnium may be analyzed in aqueous solution following digestion with hydrofluoric acid-nitric acid, or with aqua regia. The dioxide may be characterized nondestructively by x-ray methods. 

Elemental composition Hf 70.14%, F 29.86%. The compound is digested with aqua regia, the acid extract diluted and analyzed for Hf by various instrumental methods (see Hafnium). The compound may be characterized nondestructively by x-ray methods. 

Elemental composition Hg 86.22%, S 13.78%. The compound may be identified from its physical properties and also by x-ray methods. The compound may be heated in a current of air and SO2 formed may be analyzed by GC-FID or GC-FPD. Mercury(II) sulfide may be digested with aqua regia, diluted appropriately, and analyzed for mercury metal by AA using cold vapor method or by ICP-AES (see Mercury). 

Elemental composition Th 87.88%, 0 12.12%. The oxide may be identified by x-ray methods. Thorium dioxide may be analyzed by AA or ICP after digestion in aqua regia and appropriate dilution in water. 

Elemental composition Ti 59.95%, O 40.05%. The oxide may be identified by its physical properties and by x-ray methods. Titanium content may be measured by AA or ICP. The compound is digested in nitric acid or aqua regia, solubdized, and diluted sufficiently for metal analysis. 

Elemental composition W 79.30%, 0 20.70%. Tungsten trioxide may be identified by its physical properties or by x-ray diffraction methods. The oxide is either digested in aqua regia or dissolved in caustic alkalies, diluted, and analyzed for tungsten metal (See Tungsten). 

In order to dissolve adequately all selenium species including selenium metal and selenium in steel samples, an aqua regia digestion procedure was used in lieu of the existing NIOSH extraction method. 

The particulate material from the sediment traps was digested in aqua regia in a microwave digestion unit. Fe, Mn, Zn, Ca, Cr, and Cu were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) P was determined by the molybdate spectrophotometric method (28). A sediment standard (NBS No. 1645) was used regularly to check the accuracy of the sediment digestion procedure. 

In the test method, the coal or coke to be analyzed is ashed under controlled conditions, digested by a mixture of aqua regia and hydrofluoric acid, and finally dissolved in 1% nitric acid. The concentration of individual trace elements is determined by either inductively coupled plasma-atomic emission spectrometry (ICPAES) or inductively coupled plasma-mass spectrometry (ICPMS). Selected elements that occur at concentrations below the detection limits of ICPAES can be analyzed quantitatively by graphite furnace atomic absorption spectrometry (GFAA). 

For the sample digestion of sediments, Scancar et al. found that significantly lower results were obtained for chromium, nickel and cadmium when aqua regia digestion was employed, compared to total acid dissolution and acetic acid extraction methods [266]. 

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