Phases, elemental analyses extract

Soil geochemistry is widely applied in mineral exploration, and with advancing knowledge of speciation and residence phases of trace elements in soils, a variety of partial and selective extractions for chemical analysis have been developed over the past decades. Each of these methods has been designed to target and dissolve only those elements that are adsorbed onto labile phases in soil, from carrier fluids and gases that transported them from a deposit to the surface (e.g. Hall etal. 1996). 

One gram (0.0054 mol) of dithiomaleonitrile disodium salts was mixed with 1.65 mL (0.0108 mol) of 3-Phenylpropylbromide in 30 mL of acetone refluxed a 60°C for about 20 hours. The reaction time was controlled by TLC. When acetone was evaporated, the remain which was oil like product treated with CHCl to remove insoluble salts by decantation. The CHClj phase was extracted several times with Na SO. The crude oil product obtained by evaporation of the solvent was chromatographed on a silica column (eluent Chloroform). Yield 2.1 g (89%) Mw 378 g/mol (determined by GC-MS) The product is good soluble in CHCl, acetone and hexane. Elemental analysis results for Calculated C 69.80, H 5.86, N 7.40, S 16.94, Experimental 69.27, H 5.8, N 7.33, S 16.32%. 

Although AOT is also an anionic surfactant of the same type as DOLPA, haemoglobin cannot be transferred into the AOT reverse micellar phase, and most haemoglobin can be seen at the oil-water interface as a red precipitate. Adachi and Harada have reported that cytochrome c precipitated as a cytochrome c-AOT complex at low concentrations of AOT [7]. It was found that this precipitate is likewise the AOT-haemoglobin complex (AOT/haemoglobin = 120 1) from the results of elemental analysis [8]. These results indicate that the difference in the extraction ability of DOLPA and AOT might depend on the hydrophobicity of the surfactants provided to the hydrophilic proteins. 

To 3-aniino-4-iodopyridine (10.00 mmol) dissolved in 25 ml acetonitrile was added 1.67 ml trifluoroacetic anhydride at 0°C and KjCOj (30 mmol) and the mixture stirred 10 minutes at ambient temperature. To this was added bis(triphenylphosphine)-palladium(n)chloride (0.25 mmol), copper(I)iodide (0.50 mmol), and 5-chloro-l-pentyne (12.00 mmol) and the mixture refluxed 3 hours. Thereafter, the mixture was cooled, partitioned between water and EtOAc, and the organic phase extracted with water at pH 1.00. The aqueous phase was mixed with CH2CI2 and the pH raised to 10 by the addition of 2M NaOH. The organic phases were combined, dried, concentrated, and the residue dissolved in 20 ml acetonitrile. To this brownish solution was added Nal (20 mmol) and NaH (ca 55%, 20 mmol), the mixture stirred 2 hours, poured onto ice, partitioned between 100 ml apiece of water and EtOAc, and the phases separated. The organic phase was extracted 5 times with 50 ml water at pH 1.00, mixed with 100 ml CH2CI2, and the pH raised to 10 using 2M NaOH. The phases were separated, the organic phase dried, concentrated and the product isolated in 51% yield, mp = 95-96 °C after re-crystallization in t-butyl-methylether. Elemental analysis data supplied. 

The product from Step 4 (3.9 mmol) was dissolved in 200 ml toluene, cooled to -92°C, diisobutylaluminum hydride (11.3 mmol) added, and the mixture stirred at -77 °C 3 hours. It was then quenched with 5 ml methyl alcohol and 50 ml 10% hydrochloric acid. Thereafter it was diluted with 200 ml CH2CI2, washed with 100 ml saturated potassium sodium tartrate, the aqueous layer extracted with CH2CI2, and the organic phase washed with brine. The mixture was dried, concentrated, purified by chromatography on silica gel with EtOAc/hexane with a gradient of 1-15% EtOAc, and the product isolated in 18% yield, mp = 162-164°C. H- and C-NMR, IR, and elemental analysis data supplied. 

The product from Step 1 (3.03 mmol) was dissolved in 70 ml HO Ac, 1,2-phenylenediamine (6.62 mmol) dissolved in 30 ml HO Ac added, and the mixture refluxed 90 minutes. The mixture was concentrated, dissolved in 30 ml apiece CH2CI2 and water, the phases separated, and the aqueous phase further extracted with CH2CI2. The organic phases were combined, washed with 50 ml apiece NaHC03, water and brine, dried, and concentrated. The material was purified by chromatography on silica gel using CH2CI2 and the product isolated in 94% as a yellow powder. H- and C-NMR, MS, and elemental analysis data supplied. 

Ensuring high-quality analytical performance in trace analysis, if separation of sample components by extraction is indispensable, requires implementation of the appropriate extraction method and establishment of suitable operational parameters to ensure a high efficiency of extraction. Selection of extraction conditions is crucial for quantitative recovery of analyte, or at least for sufficient effectiveness. If an aqueous solution is one of the extraction phases, problems such as complex-ation, hydrolysis, and solvation can play an important role. Extraction of elements from aqueous to organic phase often requires selection of appropriate ligands and control of pH. 

Conclusion. In conclusion, a simple, rapid set of GC methods based upon hydrofluoric acid digestion and either hexane extraction or head space analysis have been developed which will allow any laboratory equipped with a GC to Identify and quantify the primary ligands and end-capping species present on the most widely used reversed-phase packing materials, l.e., octyl and octadecyl bonded phases. The method has been confirmed against elemental analysis. 

In comparison, for elemental analysis, the integrity of the analyte is not an issue, so much harsher sample pretreatment can be performed using inorganic acids. This breaks down the sample and extracts the analyte completely into the liquid phase. However, it is still necessary to ensure that the spike and sample isotopes are in the same chemical form, so repeated oxidation/reduction cycles may be necessary. This is particularly true if thermal ionization mass spectrometry (TIMS) is used, because different inorganic oxidation states can have quite different thermal properties. 

Tseng et al. [69] determined 60cobalt in seawater by successive extractions with tris(pyrrolidine dithiocarbamate) bismuth (III) and ammonium pyrrolidine dithiocarbamate and back-extraction with bismuth (III). Filtered seawater adjusted to pH 1.0-1.5 was extracted with chloroform and 0.01 M tris(pyrrolidine dithiocarbamate) bismuth (III) to remove certain metallic contaminants. The aqueous residue was adjusted to pH 4.5 and re-extracted with chloroform and 2% ammonium pyrrolidine thiocarbamate, to remove cobalt. Back-extraction with bismuth (III) solution removed further trace elements. The organic phase was dried under infrared and counted in a ger-manium/lithium detector coupled to a 4096 channel pulse height analyser. Indicated recovery was 96%, and the analysis time excluding counting was 50-min per sample. 

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