Phosphate sampling

Procedure. Dissolve 0.4 g of the phosphate sample in 2.5 M nitric acid to give 1 L in a graduated flask. Place a 10 mL aliquot of this solution in a 100 mL... 

EPA. 1979a. Environmental Protection Agency. Analysis of aryl phosphate samples. Intra-Agency memorandum from A.B. Crockett, Environmental Monitoring and Support Laboratory, Office of Research and Development to P. Hilgard, Office of Toxic Substances. 

Test 2 Mandelin s Test Dissolve 0.5 g of ammonium vanadate in 1.5 mL of water and dilute to 100 mL with sulfuric acid. Filter the solution through glass wool. Add a drop of the reagent to the primaquine phosphate sample on a white tile. A orange — violet color is produced [2]. 

John et al. [37] described a colorimetric method for the estimation of primaquine phosphate. Sample solutions of different dilutions (0.15-0.6 mL) of the drug (6-24 pg/mL) were treated with 5 mL of 1% cerric ammonium sulfate in dilute nitric acid and made up to 25 mL with water. The absorbance of the resulting light purple solution was measured at 480 nm after similar 30 min. Beer s law was obeyed from 5 30 pg/mL of primaquine phosphate. The method is applicable to bulk formulations in addition to tablets and capsule formulation. 

Procedure Add about 20 ml of anhydrous methanol to the titration vessel and titrate to the amperometric end-point with the Karl Fischer reagent. Quickly add 0.2 g of prednisolone sodium phosphate sample, stir for 1 minute and again titrate to the amperometric end-point with the Karl Fischer reagent. The difference between the two titrations gives the volume (v) of Karl Fischer reagent consumed by the sample. 

Carvalho, A. Z., Pauwels, J., De Greef, B., Vynckier, A.-K., Yuqi, W., Hoogmartens, J., and Van Schepdael, A. (2006). Capillary electrophoresis method development for determination of impurities in sodium cysteamine phosphate samples.. Pharm. Biomed. Anal. 42, 120—125. 

Results of the study with Octolig , summarized in Table 7 indicate that there was no statistically significant difference [59] between the two methods. Similar results were obtained for a capacity for arsenate [59]. The results (Table 7) were also used to see if there was a major difference between different preparations of Octolig E) by comparing capacity for phosphate (Sample 1 vs. Sample 2),... 

Fig. 4.16 shows a typical chromatogram for a standard 42pg L 1 phosphate solution and hypoxanthine peaks resulting from various phosphate samples after reaction with the enzyme. The calibration curve had a slope of 0.043 0.002 and an intercept of 0.124 0.033 with a correlation coefficient of 0.998. Linearity up to 30mg L 1 was observed. Relative standard deviation of triplicate runs was 10% or less. The detection limit, twice the signal of the blank, was determined to be 1.5mg L 1. 

Component Calcium phosphate sample (mole %) Phosphate centers (mole %)... 

Because the phosphonate-phosphate rearrangement requires P-C bond breakage and formation of the P-O bond kinetic isotope studies by means of 13C NMR were chosen.50 13C KIEs were derived from NMR analysis of substrate-o-nitro-benzaldehyde or product-phosphate. Samples of aldehyde were prepared using the dead-end method. To the solution of phosphite 3 and triethylamine in acetonitrile an excess of aldehyde was added and solution was heated at 65°C to complete conversion of phosphonate 4 to phosphate 5 monitored by 31P NMR. The aldehyde conversions 0.2-0.8 were calculated from the balance of concentrations. The changes of 13C composition were determined for carbonyl carbon atom using signal of meta aryl carbon as an internal standard. KIE 1.0223(14) was calculated from the slope of linear relationship of isotopic ratio R and fraction of reaction,... 

Most commercially available cathodic E-coat paints contain lead in the recipe, and the removal of lead from E-coat generally leads to an appreciably inferior performance on scab test [7]. The effect of lead-free E-coat on the corrosion performance of plasma interface-engineered systems was examined and the results are shown in Table 33.3. The elimination of lead resulted in significant deterioration of the corrosion protection of the phosphated samples. In a strong contrast to the conventional surface preparation, the plasma interface-engineered systems showed... 

For faster reactions the speed with which reactants can be mixed is a hmitation the mixing time must be less than the half-time. Stopped-flow techniques have been developed that permit remarkably short kinetic analysis times. Beckwith and Crouch described a stopped-flow kinetic analysis apparatus, with a mixing and dead time of less than 0.01 s, capable of analyzing 1000 phosphate samples per hour with a relative standard deviation of about 1%. Sample handUng, mixing, and gathering and evaluation of data were automated with the help of on-Une computer systems. 

Mean analyte concentrations (ppm) in phosphate samples (after Hayumbu et al., 1995)... 

Fig. 9 Differential scanning calorimetry of dicalcium phosphate samples. (A) dicalcium phosphate dihydrate (B) anhydrous dicalcium phosphate with adsorbed moisture.

Fig. 21. Stress relaxation curves (solid lines) and spectrum of relaxation times for phosphate sample in terminal region at various temperatures...

Name Diethanolamine cetyl phosphate Sample preparation Potassium bromide dispersion 1 mg / 300 mg... 

In many non-phosphate samples, uranium can be coprecipitated with magnesium hydroxide or otherwise concentrated and extracted from a sulfate system into an extractive scintillator containing a high-molecular-weight tertiary amine sulfate. 

Urine Coprecipitation with calcium phosphate sample wet ashed with nitric acid extraction and separation on Crown ether loaded chromatographic column LSC 7 dpm/L (0.82 Bq/L or 22 pCi/L) 95 5 Dietz et al. 1991... 

Table 5 Infrared and Gravimetric data for pyridine adsorption on phosphated samples...

All phosphated samples, irrespective of the preparation procedure employed, showed reduced Bronsted site densities compared with the parent, non-phosphated mixed-oxide (Table 5, column 6). In sharp contrast, Lewis site densities were always higher for the phosphate containing samples. Phosphated samples displayed a trend not too dissimilar from that obtained for sulfated samples where the gain with respect to the parent mixed oxide in Lewis sites as a function of increased phosphate loading is mirrored by a corresponding loss in Bronsted sites. This mirror effect was also apparent at the highest phosphate loading where a partial recovery of Bronsted sites was matched by a loss in Lewis sites. The consequence was that the total number of acid sites remained fairly constant across the series. 

The phosphated samples on the other hand displayed little textural changes (Table... 

Crowson RA, Showers WJ, Wright EK, Hoering TC (1991) Preparation of phosphate samples for oxygen isotope analysis. Anal Chem 63 2397-2400... 

The situation changes when the defect is prepared just down to zinc and the kinehcs of zinc dissolution are rather slow. In this case, the cathodic delamination determines the kinetics of undermining. The delaminated area of the phosphated sample is now smaller than for the defect down to steel, whereas the just alkaline cleaned sample shows delamination that is much faster than in the case of the defect down to steel. This example shows how complex the corrosion mechanisms are and that no generally accepted mechanism can be found in the literature. 

FIGURE 1 SEM-images of the zinc phosphate samples obtained in the presence of E-30 (a), TX-lOO ), polyvinyl alcohol (c) and polyethylene glycol (d). 

This method is used to estimate the amount of unsaponifiable impurities in tricresyl phosphate. Sample of plasticizer is refluxed with water solution of NaOH for 1 h. The saponified material is extracted with petroleum ether. The extracted material is evaporated in a tared evaporation dish at 75°C and reminder determined. The nonvolatile residue consists the unsaponifiable contents of tricresyl phosphate. 

Poly-(diallyl-phthalate) ABS PC-ABS blend Dechlorane Plus Octabromodiphenyl oxide Brominated phenol, triphenyl phosphate sample at 950°C capillary, 30 m X 0.25 mm I.D., 1.0 p.m film 10 C/minto320°C, hold for 18 min 15 50 mass range) detector r = 300°C 30/1 injection split ... 

Fig. 2 illustrates the CCC chromatogram of water-soluble vitamins obtained with the above solvent system, which comprise 1-butanol and aqueous 0.15 M monobasic potassium phosphate, including 1.5% of 1-octanesulfonic acid sodium salt. Riboflavin sodium phosphate, cyanocobalamin, riboflavin, pyridoxine hydrochloride, and thiamine nitrate were separated using the lower phase as the mobile phase. Riboflavin was found as an impurity contained in the riboflavin sodium phosphate sample. 

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