Phosphate, sodium dihydrogen

Sodium dihydrogen phosphate-disodium hydrogen phosphate [39413-44-0]... 

R. Parsons, F. G. R. Zobel. The interphase between mercury and aqueous sodium dihydrogen phosphate. J Electroanal Chem 9 333-348, 1965. 

FIGURE 7.6 Effect of column length on the separation efficiency. Two different Fractogel EMD BioSEC columns (A 600 X 16 mm, B 1000 X 16 mm) were tested using BSA, ovalbumin, and cytochrome c (S/S/3 mg/ml) as sample (20 m/VI sodium dihydrogen phosphate, 300 m/VI NaCI, pH 7.2 0.5 ml/min). Better resolution can be achieved using longer columns. 

Then 0.75 cc of freshly distilled ethyl formate is added. The air in the system is replaced with nitrogen and 150 mg of sodium hydride (as a 57% dispersion in mineral oil) is added. The mixture is stirred under nitrogen at room temperature for three hours. Then 15 cc of a saturated aqueous solution of sodium dihydrogen phosphate is added and the product is extracted into ether. 

The ether extracts are extracted with 2 N sodium hydroxide and the sodium hydroxide extracts are acidified with sodium dihydrogen phosphate and extracted again into ether. 

Methyl-5-oxo-l-phenyl-4,5-dihydropyrazol-4-ylidene)-2,3-dihydro-l//-azepine (3), formed in 62% yield by the condensation of 2-amino- or 2-butoxy-37/-azepine with 3-methyl-l-phenylpyrazol-5(4//)-one, with Meerwein s reagent yields the tetrafluoroborate salt 4 which, on treatment with sodium dihydrogen phosphate, liberates the free base 5.64... 

Acid phosphates (e.g., orthophosphates) such as phosphoric acid or sodium dihydrogen phosphate)... 

Phosphate (present as sodium dihydrogen phosphate) does not interfere below a level of 1.0 wt %. Chloride (present as sodium chloride) does not interfere at a level of 3 wt %. 

Explain what happens to (a) the pH of a solution of phosphoric acid after the addition of solid sodium dihydrogen phosphate (b) the percentage deprotonation of HCN in a hydrocyanic acid solution after the addition of hydrobromic acid (c) the concentration of H ions when pyridinium chloride is added to an aqueous solution of the base pyridine. 

Table 2.1 HPLC capacity factors for secbuto-barbitone and vinbarbitone with an octadecyl silyl stationary phase and mobile phases of methanoiyO.l M sodium dihydrogen phosphate (40 60) at (a) pH 3.5, and (b) pH 8.5. From Moffat, A.C. (Ed.), Clarke s Isolation and Identification of Drugs, 2nd Edn, The Pharmaceutical Press, London, 1986. Reproduced by permission of The Royal Pharmaceutical Society...

C17-0035. Write all the acid-base equilibrium reactions that have major species as reactants for a solution of sodium dihydrogen phosphate, NaH2 PO4. 

Write formulas for each of the following compounds (a) calcium hydrogen carbonate, (b) disodium hydrogen phosphate, (c) sodium dihydrogen phosphate, and (d) calcium dihydrogen phosphate. 

HPLC-grade formic acid (1 mL) sodium dihydrogen phosphate (12g.L ) sodium hydrogen carbonate (5 g) sodium vanillate stock solution (50 mg mL )... 

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