4.1.3. BUFFER SOLUTIONS

1 EUROPEAN PHARMACOPOEIA BUFFER solutionsZirconium standard solution (1 g/L Zr). nitrate Requivalent to g ofZrO(NO3)2,2H2 Oinamixtureof2volumesofhydrochloricacid Rand 8 volumes ofwater Rand dilute to mL withthe same mixture of BUFFER SOLUTIONSB uffered acetone g ofsodium acetate Rand 42 g ofsodiumchloride Rinwater R, M hydrochloric acidand 150 mL ofacetone Rand dilute to 500 mL withwater solution pH g ofpotassium chloride Rinwater Rand mL M hydrochloric acid. Dilute to mL withwater BUFFER solution pH g ofdisodium hydrogen phosphate Rand gofpotassium dihydrogen phosphate Rinwater Rand diluteto mL with the same solvent.

2 If necessary adjust thepH withphosphoric acid BUFFER solution pH g ofammonium sulfate Rinwater Rand diluteto mL with the same solvent (Solution A). Carefully andwith constant cooling stir 14 mL of sulfuric acid R into about400 mL ofwater R; allow to cool and dilute to mL withwater R(Solution B). Mix equal volumes of SOLUTIONS A and the pH if solution pH mL ofphosphoric acid Rwith mL of a 40 g/Lsolution ofsodium hydroxide Rand dilute to mL withwater solution pH 100 g ofpotassium dihydrogen phosphate Rin800 mL ofwater R.

3 Acid Rand dilute to mL withwater solution pH g ofdilute phosphoric acid Radd 250 mL ofwater the pH withdilute sodium hydroxide solution Randdilute to mL withwater BUFFER solution pH g ofsodium dihydrogen phosphate Rin 900 mL ofwater R, acid Rand dilute to1000 mL with the same solution pH g ofcitric acid Rin 200 mL of1 Msodiumhydroxideand dilute to 1000 mL withwater R. Dilute mLof this solution to mL M hydrochloric M Citrate BUFFER solution pH g ofcitric acid Rin 80 mL ofwater with1 M sodium hydroxideand dilute to mL withwater M Phosphate BUFFER solution pH g ofanhydrous sodium dihydrogen phosphate Rinwater R,adjustthepHwithdilute phosphoric acid R1anddilute to 1000 mL withwater BUFFER solution pH mL ofphosphoric acid Rwith 100 mL ofwater to 900 mL with the same solvent.

4 Adjust to pH withstrong sodium hydroxide solution Rand dilute to 1000 mLwithwater BUFFER solution pH g ofpotassium dihydrogen phosphate Rin900 mL ofwater acid Rand dilute to mL withwater BUFFER solution pH 900 mL of a 4 g/L solution ofsodium dihydrogenphosphate R, BUFFER solution pH a g/L solution ofdisodium hydrogen phosphate Rto pH withdilute phosphoric acid to mL withwater solution pH g ofammonium acetate Rin 25 mL ofwater Rand add mL ofhydrochloric acid if necessary withdilute hydrochloric acid Rordiluteammonia R1.

5 Dilute to mL withwater BUFFER solution pH g ofpotassium dihydrogen phosphate RinwaterRand dilute to mL with the same solvent. Adjustthe pH withphosphoric acid solution pH mL M potassium hydrogen phthalate mL M hydrochloric acid. Dilute to mL withwater solution pH mL ofacetic acid Radd 60 mL ofethanol (96 percent) Rand 20 mL ofwater R. Adjust to pH by the additionofammonia R. Dilute to mL withwater copper sulfate solution pH g ofcopper sulfate Rand g ofammoniumacetate Rindilute acetic acid Rand dilute to mL acetate BUFFER solution pH ( M).

6 822 mg ofsodium acetate Rin 100 mL ofwater R(solution A). Dilute mL ofglacial acetic acid Rin 250 mLofwater R(solution B). Titrate 100 mL of solution B usingabout 20 mL of solution BUFFER solution pH 136 g ofsodium acetate Rand 77 g ofammoniumacetate Rinwater Rand dilute to mL with the samesolvent; add mL ofglacial acetic acid Rand BUFFER solution pH g ofpotassium hydrogen phthalate Rin 50 mLofwater R, M sodium hydroxideand dilute mL withwater BUFFER solution pH g ofammonium acetate Rinwater acetic acid Rand dilute to mL withwater M Phosphate BUFFER solution pH g ofpotassium dihydrogen phosphate mL ofwater ( )

7 Of the solution is acetate BUFFER solution pH 63 g ofanhydrous sodium acetate Rinwater R,add90 mLacetic acid Rand adjust to pH , and dilute to 1000 mLwithwater BUFFER solution pH g ofsodium acetate Rin 50 mL ofwater R, g ofglacial acetic acid Rand dilute to mL withwater Notices (1) apply to all monographs and other BUFFER solutionsEUROPEAN PHARMACOPOEIA BUFFER solution pH g ofsuccinic acid Rin a mixture of 600 mL ofwater Rand 82 mL of1 M sodium hydroxideand dilute mL withwater BUFFER solution pH g ofsodium acetate Rin 500 mL ofwater 250 mL of this solution with 250 mL ofdilute aceticacid R.

8 Shake twice with a freshly prepared, filtered, g/Lsolution ofdithizone Rinchloroform Runtil the extract is colourless. Filter theaqueous layer to remove traces of carbon BUFFER solution pH g ofsodium acetate Rin 500 mL ofwater mL of this solution with 250 mL ofdilute acetic acid BUFFER solution pH acetic acid Radd100 mL M potassium hydroxideand about 250 mL ofwater R. Mix. Adjust the pH to with a 6 g/L solution ofacetic acid Ror M potassium hydroxideand dilute mL withwater BUFFER solution pH a solution containing g/L ofcitric acid g/L ofsodium hydroxide acid BUFFER solution pH g ofpotassium dihydrogen phosphate Rin800 mL ofwater dilute to 1000 mL withwater solution pH g ofpotassium hydrogen phthalate Rin M sodium hydroxide.

9 Dilute to mL withwater M Phosphate BUFFER solution pH appropriate volumes of a g/L solution ofdisodiumhydrogen phosphate Rwith a g/L solution ofsodiumdihydrogen phosphate monohydrate Rto obtain pH ( ).Acetate-edetate BUFFER solution pH 250 g ofammonium acetate Rand 15 gsodiumedetate Rin 400 mL ofwater Rand add 125 mL ofglacialacetic acid solution pH g ofsodium acetate Rin 50 mL ofwater R,heating to 35 C if necessary. After cooling, slowly add 10 mLofanhydrous acetic acid R. Shake and dilute to mL withwater BUFFER solution pH g ofpotassium dihydrogen phosphate Rinwater Rand dilute to mL with the same solvent(solution A).

10 Dissolve g ofdisodium hydrogenphosphate Rinwater Rand dilute to mL with the samesolvent (solution B). Mix mL of solution A and mL ofsolution BUFFER solution pH mL of a g/L solution ofanhydrous disodiumhydrogen phosphate Rand mL of a 21 g/L solution ofcitric acid BUFFER solution pH g ofpotassium dihydrogen phosphate Rinwater (solution A). Dissolve g ofdipotassium hydrogenphosphate Rinwater Rand dilute to mL with the samesolvent (solution B). Mix mL of solution A and mL ofsolution B. If necessary, adjust to pH using solution A orsolution BUFFER solution pH g ofdisodium hydrogen phosphate dihydrate Rand g ofpotassium dihydrogen phosphate Rinwater Rand dilute to mL with the same BUFFER solution pH 100 g ofammonium acetate Rin 300 mL ofwater R,add mL ofglacial acetic acid R.