Water, acid digested

Water Acid digestion in mixture of nitric, sulfuric, and perchloric acids Electrothermal AAS 0.2 pg Ni/L fluids 98% at 5 pg Ni/L 97%at8pg Ni/L lARC 1986 (Method 11)... 

Water Acid digestion Spectrophotometric measurement (total strontium) (Method 911.03) No data No data AOAC 1990... 

Digest nail samples with concentrated nitric acid heat at 65°C for 1 hour cool and dilute with de-lonzed water Acid digestion with mixtures of different acids distill volatile elements... 

Opa.nte. There are two methods used at various plants in Russia for loparite concentrate processing (12). The chlorination technique is carried out using gaseous chlorine at 800°C in the presence of carbon. The volatile chlorides are then separated from the calcium—sodium—rare-earth fused chloride, and the resultant cake dissolved in water. Alternatively, sulfuric acid digestion may be carried out using 85% sulfuric acid at 150—200°C in the presence of ammonium sulfate. The ensuing product is leached with water, while the double sulfates of the rare earths remain in the residue. The titanium, tantalum, and niobium sulfates transfer into the solution. The residue is converted to rare-earth carbonate, and then dissolved into nitric acid. 

Phosphorus and Silicon in Waters, Effluents and Sludges [e.g. Phosphorus in Waters, Effluents and Sludges by Spectrophotometry-phosphomolybdenum blue method. Phosphorus in Waters and Acidic Digests by Spectrophotometry-phosphovanadomolybdate method. Ion Chromatographic Methods for the Determination of Phosphorus Compound, Pretreatment Methods for Phosphorus Determinations, Determination of silicon by Spectrophotometric Determination of Molybdate Reactive Silicon-1 -amino-2-naphthol-4, sulphonic acid (ANSA) or Metol reduction methods or ascorbic acid reduction method. Pretreatment Methods to Convert Other Eorms of Silicon to Soluble Molybdate Reactive Silicon, Determination of Phosphorus and Silicon Emission Spectrophotometry], 1992... 

Standard test for hydrolytic stability. The hydrolytic stability of the chlorinated resins was determined by the following test procedure. An acid digestion autoclave having a volume of 125 ml is charged with 40 ml of resin and 28 ml of deionized water. The bomb is sealed and transferred into an oven, pre-heated to 200 °C. The test is continued for 24 hours. The bomb is removed and cooled to ambient temperature. The liquid is separated from the resin and the chlorine content analyzed while the resin is washed thoroughly and its acid capacity is determined as described in section 5. The test results are shown in Table 2. 

Soil, wastes, and groundwater Acid digestion of sample, dilution with water, and filtration AAS (EPA method 7420) GFAAS (EPA method 7421) 0.1 mg/L 1 pg/L No data No data EPA 1986e... 

Selenium (IV) adsorbed as selenotrisulfate was then eluted from the column with either 0.1 M penicillamine or 0.1M cysteine. The eluate was then subjected to an acid digestion procedure to reduce selenium to the tetravalent state with diaminonaphthalene for fluorometric determination. Approximate agreement with the tellurium coprecipitation method was obtained. The application of both methods to the analysis of estuarine waters permitted the separate determination of both selenium (IV) and selenium (VI), since the tellurium coprecipitation methods did not differentiate between the two species. 

The REE analysis was carried out in twenty two sand samples by using 0.1 g of dried sample (mesh 200) and digested with strong acid. Digestion was performed in teflon vessels using 4 ml of HCI 04 and 10 ml HF. This mixture was heated and residue dissolved in distilled water. 

River water al. Hexane extraction coupled with chromic acid digestion Capi11 ary GC/ECD No data 99.4 (mi rex) 100.9 (photomi rex)... 

Elemental composition Ce 42.96%, N 12.88%, O 44.15%. The aqueous solution of this water-soluble compound may be analyzed directly for Ce (without any acid digestion) by AA or ICP spectrophotometry, and for the nitrate ion by ion chromatography or nitrate ion-selective electrode. The solution may require sufficient dilution for analysis. 

Elemental composition Co 38.03%, 8 20.68%, O 41.29%. 8ohd cobalt(Il) suhate is brought to aqueous phase by acid digestion, appropriately diluted, and analyzed for cobalt by flame or furnace AA or ICP. It also may be determined in the solid crystalline form by x-ray methods. The suhate anion may be measured by dissolving an accurately measured small amount of salt in measured quantities of water and analyzing the solution by ion chromatography. 

Elemental composition Au 79.44%, H 1.22%, O 19.35%. The hydrated salt containing three water molecules has 65% gold. The compound may be acid digested, diluted appropriately, and analyzed for gold by various instrumental methods (see Gold). 

Elemental composition An 89.15%, 0 10.86%. Gold(III) oxide is acid digested, the acid extract diluted appropriately with water and analyzed for gold by atomic absorption spectrophotometry or other instrumental techniques (see Gold). 

Elemental composition (of anhydrous MgS04) Mg 20.20%, S 26.63%, O 53.16%. The water of crystalization may be measured by thermogravimetric methods. Magnesium may be analyzed by AA or ICP-AES following acid digestion. 

Elemental composition Na 19.16%, P 25.81%, H 1.68%, 0 53.34%. The compound is dissolved in water and analyzed by AA or ICP to determine its sodium content. The phosphorus is analyzed as total P by acid digestion and colorimetric method (See Phosphorus and also Phosphoric Acid). 

In one acid digestion process, monazite sand is heated with 93% sulfuric acid at 210°C. The solution is diluted with water and filtered. Filtrate containing thorium and rare earths is treated with ammonia and pH is adjusted to 1.0. Thorium is precipitated as sulfate and phosphate along with a small fraction of rare earths. The precipitate is washed and dissolved in nitric acid. The solution is treated with sodium oxalate. Thorium and rare earths are precipitated from this nitric acid solution as oxalates. The oxalates are filtered, washed, and calcined to form oxides. The oxides are redissolved in nitric acid and the acid solution is extracted with aqueous tributyl phosphate. Thorium and cerium (IV) separate into the organic phase from which cerium (IV) is reduced to metalhc cerium and removed by filtration. Thorium then is recovered from solution. 

Insoluble silica residues are removed by filtration. The solution now contains beryllium, iron, yttrium, and the rare earths. The solution is treated with oxalic acid to precipitate yttrium and the rare earths. The precipitate is calcined at 800°C to form rare earth oxides. The oxide mixture is dissolved in an acid from which yttrium and the rare earths are separated by the ion-exchange as above. Caustic fusion may be carried out instead of acid digestion to open the ore. Under this condition sihca converts to sodium sihcate and is leached with water. The insoluble residue containing rare earths and yttrium is dissolved in an acid. The acid solution is fed to an ion exchange system for separating thuhum from other rare earths. 

Iowa. Modem industrial prepns start with agricultural residues such as oat hulls, corn cobs, rice hulls, bran, etc, which have a relatively high pentosan content (Ref 10). In these processes pentosans are hydrolyzed to pentoses by acid digestion, and these split out water internally to form forfurals ... 

Another result of the requirements to distribute homogeneous test material is that some pretreatment steps usually performed on routine samples are not done on the interlaboratory sample. For example, in interlaboratory rounds for the determination of metals by inductively coupled plasma, the test material is often a solution of the metals in water. Often a method requires extraction of the metals by acid digestion of the field sample, a procedure that will have significant uncertainty in terms of recovery of analyte. 

Cerous Monohydrogen Ortkoarsenate, Ce2(HAs04)3, is obtained as a white powder, insoluble in water, by digesting cerous oxide with aqueous arsenic acid.17 It dissolves in excess of the latter and, if the solution is evaporated, a gelatinous mass, probably cerous dihydrogen orthoarsenate, Ce(H2As04)3, is obtained. 

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