Analysis: Dry at 100

to constant weight.

Acceptance criteria: NMT 7.0%

Residue on Ignition

281

Analysis: Ignite 500 mg with 1 mL of sulfuric acid.

Acceptance criteria: NMT 75 mg (15%)

Microbial Content: NMT 104 cfu/g

Nitrogen Content (Reagent test)

Analysis: Determine by the Kjeldahl method.

Acceptance criteria: 9.0%–14.0% is found

Amino Nitrogen: 5.0%–5.6%

USP38

Pancreatin

[8049-47-6]—Use a grade of pancreatin which meets the USP requirements for amylase, lipase, and protease activities specified for the official substance.

Change to read:

Papaic Digest of Soybean Meal —A soluble nutrient material prepared by the action of the enzyme papain on soybean meal followed by suitable purification and concentration. It contains fermentable carbohydrates.

Loss on Drying

Analysis: Dry it at 100

to constant weight.

Acceptance criteria: NMT 7.0%

Residue on Ignition (Reagent test)

Analysis: Ignite 500 mg with 1 mL of sulfuric acid.

Acceptance criteria: NMT 75 mg (15.0%)

USP38

Microbial Content: NMT 104 cfu/g

Nitrogen Content (Reagent test)

Analysis: Determine by the Kjeldahl method, using a test specimen previously dried at 105

to constant weight.

Acceptance criteria: NLT 8.5% is found.

Amino Nitrogen: 1.8%–3.2%

USP38

Paper, Odorless Absorbent —See Filter Paper, Quantitative.

Para-aminobenzoic Acid (p-Aminobenzoic Acid),

H2NC6H4COOH—137.14

[150-13-0]—White or slightly yellow crystals or crystalline powder, becoming discolored on exposure to air or light. One g dissolves in 170 mL of water, in 9 mL of boiling water, in 8 mL of alcohol, and in 50 mL of ether. Freely soluble in solutions of alkali hydroxides and carbonates; soluble in warm glycerin; sparingly soluble in diluted hydrochloric acid; slightly soluble in chloroform. Store in tight, light-resistant containers.

Assay— Accurately weigh about 300 mg, previously dried at 105

for 2 hours, and transfer to a beaker or casserole. Add 5 mL of hydrochloric acid and 50 mL of water, and stir until dissolved. Cool to about 15

, add about 25 g of crushed ice, and slowly titrate with 0.1 M sodium nitrite VS until a glass rod dipped into the titrated solution produces an immediate blue ring when touched to starch iodide paper. When the titration is complete, the endpoint is reproducible after the mixture has been allowed to stand for 1 minute. Each mL of 0.1 M sodium nitrite is equivalent to 13.71 mg of C7H7NO2. Not less than 98.5% is found.

: between 186

and 189

— Dry it at 105

for 2 hours: it loses not more than 0.2% of its weight.

Residue on ignition (Reagent test): not more than 0.1%.

Paraformaldehyde,

(CH2O)n

[30525-89-4]—Fine, white powder.

Assay— Transfer about 1 g, accurately weighed, to a 250-mL conical flask containing 50.0 mL of 1 N sodium hydroxide VS, and mix by swirling. Immediately, and slowly, add 50 mL of hydrogen peroxide TS, previously neutralized to bromothymol blue, through a small funnel placed in the neck of the flask. After the reaction moderates, rinse the funnel and inner wall of the flask with water, allow the solution to stand for 30 minutes, add bromothymol blue TS, and titrate the excess alkali with 1 N sulfuric acid VS. Each mL of 1 N sodium hydroxide is equivalent to 30.03 mg of HCHO: not less than 95% is found.

Residue on ignition: not more than 0.1%.

Solubility in ammonia— Dissolve 5 g in 50 mL of ammonia TS: a practically clear, colorless solution results.

Reaction— Shake 1 g with 20 mL of water for about 1 minute, and filter: the filtrate is neutral to litmus.

Pectate Lyase

[9015-75-2]—An enzyme obtained from Aspergillus sp. Light brown, viscous liquid. Specific gravity is about 1.5. It is readily soluble in water. It is supplied at approximately 14 units per mL at pH 8.0 in Tris-HCl buffer [50 mM of Tris(hydroxymethyl)aminomethane containing 1 mM of CaCl2, pH 8.0] in a solution of 50% glycerol and 0.02% sodium azide. One unit is defined as the enzyme activity that produces 1 µmol of unsaturated product per minute.

Activity—

Pectin solution— Transfer a quantity of Pectin, equivalent to 0.05 g on the dried basis, to a 100-mL volumetric flask. [Note—Pectin has a molecular weight of 103,000 Da; its degree of esterification (percentage of galacturonic acid groups substituted with methyl) is 12. ] Moisten with 0.1 mL of 2-propanol. Add 50 mL of water to the flask, and mix the solution with a magnetic stirrer. Use 0.5 N sodium hydroxide to adjust the solution to a pH of 12. Stop the stirrer, and allow the solution to stand undisturbed at room temperature for 15 minutes. Adjust the solution with 0.5 N hydrochloric acid to a pH of 8.0. Dilute with water to volume.

Tris Buffer solution— Transfer 6.055 g of Tris(hydroxymethyl)aminomethane and 0.147 g of calcium chloride to a 1000-mL volumetric flask containing 950 mL of water, and mix. Adjust the solution with 1 N hydrochloric acid to a pH of 8.0. Dilute with water to volume.

Diluted pectate lyase— Transfer 0.5 mL of Pectate Lyase to a 50-mL volumetric flask, dilute with Tris buffer solution to volume, and mix.

Procedure— Add the solutions set forth in the table below to quartz cuvettes.

Label	Tris Buffer Solution (mL)	Pectin Solution (mL)	Diluted Pectate Lyase (mL)	Water (mL)
Enzyme blank	0.5	1.0	0	1.0
Test blank	0.5	0	0.5	1.5
Test solution	0.5	1.0	0.5	0.5

Perform the test on the solutions so obtained, using a suitable UV-Vis spectrophotometer (see Spectrophotometry and Light-Scattering

851

) and using water as the blank. Mix the solutions well at time 0, and immediately measure the absorbances at 235 nm. Record the value for the Enzyme blank, A0

EB ; for the Test blank, A0

TB ; and for the Test solution, A0

TS . After incubation at room temperature for 30 minutes, determine the absorbance again at 235 nm for the Enzyme blank, A30

EB ; for the Test blank, A30

TB ; and for the Test solution, A30

TS . One unit is defined as the enzymatic activity that produces 1 µmol of unsaturated product from pectin per minute. Calculate the Pectate Lyase activity, in units per mL, using the following formula:

50(103)[(A30

A30

TB)

(A0

TB)]/30

235L

in which 50 is the volume, in mL, of Diluted pectate lyase; 103 is the unit conversion factor; 30 is the time, in minutes, of the reaction;

235 is the molar extinction coefficient, in M

1 cm

1, of the reaction product (4600 M

1cm

1); and L is the path length, in cm, of the reaction cuvette (1 cm). Alternatively, these solutions, after being mixed in the cuvettes, can be immediately measured at 235 nm continuously in a recording UV-Vis spectrophotometer set up for kinetic assays. The result is obtained by correcting the blank determination, using the Enzyme blank and the Test blank.

Penicillinase —See Beta-lactamase.

Pentadecane,

C15H32—212.41

[629-62-9]—Colorless liquid.

Assay— Inject an appropriate specimen into a gas chromatograph (see Chromatography

) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 280

; the detector temperature is maintained at 300

; and the column temperature is maintained at 180

and programmed to rise 10

per minute to 280

. The area of the C15H32 peak is not less than 99% of the total peak area.

: between 1.430 and 1.434 at 20

Add the following:

1-Pentadecanol

(Pentadecyl Alcohol, n-Pentadecanol),

C15H32O—228.41

[

629-76-5]—Use a suitable grade with a content of NLT 98%.

2S (USP38)

Pentafluoropropanoic Acid (Pentafluoropropionic Acid),

C3HF5O2—164.03

[422-64-0]—Use a suitable grade with a content of NLT 97%.

Pentane (n-Pentane),

C5H12—72.15

[109-66-0]—Clear, colorless, flammable liquid. Very slightly soluble in water. Miscible with alcohol, with ether, and with many organic solvents. Specific gravity: about 0.62.

Boiling range (Reagent test)— Not less than 95% distils between 34

and 36

1-Pentanesulfonic Acid Sodium Salt —See Sodium 1-Pentanesulfonate.

2-Pentanone,

C5H10O—86.13

[107-87-9]—Use a suitable grade.

Pepsin

[9001-75-6]—Use Pepsin (Enzyme Preparations) FCC, having an activity of 1.0 to 1.17 Pepsin units per mg. Pepsin of higher activity may be reduced to this activity by admixture with pepsin of lower activity or with lactose.

Pepsin, Purified —A white or yellowish-white powder, spongy mass, or translucent scales or granules. Freely soluble in water, producing more or less opalescence; practically insoluble in alcohol, in chloroform, and in ether. Purified Pepsin used in the second tier of the Dissolution test has an activity that is determined by the following method.

Activity—

Pepsin solution— Transfer about 2.5 mg of Purified Pepsin, accurately measured, to a 100-mL volumetric flask, dilute with 10 mM hydrochloric acid to volume, and mix. [Note—Prepare immediately before use. ]

2.0% hemoglobin solution—Dissolve and dilute 2.5 g of bovine hemoglobin with water to 100 mL. Dilute 80 mL of this solution with 0.3 M hydrochloric acid to a volume of 100 mL.

Trichloroacetic acid solution— Dilute 5 g of trichloroacetic acid with water to 100 mL.

Test Solution— Transfer 5.0 mL of 2.0% Hemoglobin solution to a suitable container equilibrated at 37

. Add 1.0 mL of Pepsin solution, mix by swirling, and incubate at 37

for 10 minutes. Immediately add 10.0 mL of Trichloroacetic acid solution, mix by swirling, and incubate at 37

for 5 minutes. Pass through a filter having a 0.8-µm or finer porosity.

Control solution— Transfer 5.0 mL of 2.0% Hemoglobin solution to a suitable container equilibrated at 37

. Mix by swirling, and incubate at 37

for 10 minutes. Immediately add 10.0 mL of Trichloroacetic acid solution and 1.0 mL of Pepsin solution, mix by swirling, and incubate at 37

for 5 minutes. Pass through a filter having a 0.8-µm or finer porosity.

Procedure— Determine the absorbances of the Test solution and Control solution, in 1-cm cells, at a wavelength of about 280 nm, using water as the reference. Calculate the activity of the portion of Purified Pepsin taken by the formula:

10,000(AU

AC)

in which AU and AC are the absorbances of the Test solution and the Control solution, respectively.

Change to read:

Peptic Digest of Animal Tissue (a bacteriological peptone)—Tan powder, having a characteristic, but not putrescent, odor. Soluble in water; insoluble in alcohol and in ether. An autoclaved solution (2 in 100) is clear and is neutral or nearly so in its reaction.

Loss on Drying

Analysis: Dry at 100

to constant weight.

Acceptance criteria: NMT 7.0%

Residue on Ignition

281

Analysis: Ignite 500 mg with 1 mL of sulfuric acid.

Acceptance criteria: NMT 75 mg (15%)

USP38

Microbial Content: NMT 104 cfu/g

Nitrogen Content

Analysis: Determine by the Kjeldahl method, using a test specimen previously dried at 105

to constant weight.

Acceptance criteria: Between 9.0% and 14.0%

Amino Nitrogen: 2.7%–3.7%

USP38

Peptone, Dried (Meat Peptone) —Reddish-yellow to brown powder, having a characteristic, but not putrescent, odor. Soluble in water, forming a yellowish-brown solution having a slight acid reaction; insoluble in alcohol and in ether.

Nitrogen compounds (Reagent test)— Determine by the Kjeldahl method, using a test specimen previously dried at 105

to constant weight: between 12% and 18% of nitrogen is found.

Residue on ignition (Reagent test)— Ignite 500 mg with 1 mL of sulfuric acid: the residue weighs NMT 75 mg (15.0%).

— Dry it at 105

to constant weight: it loses NMT 7.0% of its weight.

Coagulable protein— Heat a filtered solution (1 in 20) to boiling: no precipitate forms.

Microbial content— NMT 104 cfu/g

Perchloric Acid (70 Percent Perchloric Acid),

HClO4—100.46

[7601-90-3]—Use ACS reagent grade (containing between 69.0% and 72.0% of HClO4).

Periodic Acid,

H5IO6—227.94

[10450-60-9]—White to pale yellow crystals. Very soluble in water. Undergoes slow decomposition to iodic acid. Use ACS reagent grade.

Petroleum Benzin —See Hexane, Solvent.

Phases for Gas Chromatography —See phases for gas chromatography in the Chromatographic Columns section under Chromatography

Phenacetin

[62-44-2]—Use a suitable grade.

1,10-Phenanthroline (Orthophenanthroline),

C12H8N2·H2O—198.22

[5144-89-8]—Use ACS reagent grade.

o-Phenanthroline Monohydrochloride Monohydrate,

C12H8N2·HCl·H2O—234.69

[3829-86-5]—Use a suitable grade.

Phenol

[108-95-2]—Use ACS reagent grade.

Phenol Red, Sodium,

C19H13O5SNa—376.4

[34487-61-1]—Red to brown powder. Use ACS reagent grade.

Phenolsulfonphthalein —Use Phenol Red (see Indicators under Indicators and Indicator Test Papers).

Phenoxybenzamine Hydrochloride [N-(2-Chloroethyl)-N-(1-methyl-2-phenoxyethyl)benzylamine Hydrochloride],

C18H22ClNO·HCl—340.29

[63-92-3]—White, crystalline powder.

: between 137

and 140

Absorptivity— Its absorptivity, 1%, 1 cm, in the range of 272 nm to 290 nm, in chloroform solution is about 178.

3-Phenoxybenzoic Acid,

C13H10O3—214.22

[3739-38-6]—Use a suitable grade.

: between 149

and 150

2-Phenoxyethanol,

C6H5OCH2CH2OH—138.16

[122-99-6]—Colorless, slightly viscous liquid. Soluble in water. Miscible with alcohol, with acetone, and with glycerin. Density: about 1.107.

Assay— To 2 g, accurately weighed, add 10 mL of a freshly prepared solution made by dissolving 25 g of acetic anhydride in 100 g of anhydrous pyridine. Swirl to mix the liquids, heat on a steam bath for 45 minutes, add 10 mL of water, heat for 2 additional minutes, and cool. Add 10 mL of normal butyl alcohol, shake vigorously, add phenolphthalein TS, and titrate with 1 N sodium hydroxide VS. Perform a blank test using the same quantities of the same reagents, and in the same manner, and make any necessary correction. Each mL of 1 N sodium hydroxide is equivalent to 138.2 mg of C8H10O2. Not less than 99% is found.

Phenol— Add 0.2 mL of it to 20 mL of water, mix, and to 5 mL of the mixture add 0.2 mL of Millon's reagent. Warm the solution at 60

for 90 seconds, and allow to stand: no pink or red color is produced within 1 minute.

Phenyl Ether —See Diphenyl Ether.

Phenyl Isocyanate,

C6H5NCO—119.12

[103-71-9]—Clear, colorless to straw-yellow liquid of medium volatility. [Caution—Phenyl Isocyanate is a violent lacrimator, and the vapor is highly toxic. Handle with care. ]

Assay— Transfer 250 mg, accurately weighed, to a glass-stoppered, 250-mL flask. Exercise care to avoid loss by volatilization, and avoid breathing the vapor. Add 20 mL of butylamine solution (25 g of butylamine diluted to 1000 mL with dioxane previously dried over potassium hydroxide pellets), insert the stopper in the flask, and allow to stand for 15 minutes. Add a few drops of methyl red TS and 25 mL of water, and titrate the excess amine with 0.1 N sulfuric acid VS. Perform a blank titration on 20 mL of the butylamine solution (see Residual Titrations

541

). Subtract the volume of 0.1 N sulfuric acid consumed in the test specimen titration from that consumed in the blank titration. Each mL of 0.1 N sulfuric acid, representing this difference, is equivalent to 11.91 mg of C6H5NCO: not less than 97.0% of C6H5NCO is found.

2-Phenylacetamide (

-Phenylacetamide),

C8H9NO—135.16

[103-81-1]—Bimorphous plates or leaflets. Slightly soluble in water. Use a suitable grade.

: between 156

and 158

dl-Phenylalanine,

C9H11NO2—165.19

[150-30-1]—Use a suitable grade.

o-Phenylenediamine Dihydrochloride,

C6H8N2·2HCl—181.1—White powder.

Assay— When tested by thin-layer chromatography, with the use of plates coated with chromatographic silica gel mixture and a developing system consisting of a mixture of butyl alcohol, water, and acetic acid (12:5:3), and examined under short-wavelength UV light, a single spot is exhibited, with trace impurities.

p-Phenylenediamine Dihydrochloride —See p-Phenylenediamine Hydrochloride.

p-Phenylenediamine Hydrochloride (1,4-Diaminobenzene Dihydrochloride),

C6H8N2·2HCl—181.06—White to pale tan crystals or crystalline powder, turning red on exposure to air. Freely soluble in water; slightly soluble in alcohol and in ether. Preserve in well-closed containers, protected from light.

Insoluble matter— Dissolve 1 g in 10 mL of water: the solution is clear and complete.

Molar absorptivity (see Spectrophotometry and Light-scattering

851

)— Dissolve 60 mg in 100.0 mL of water, and mix. Pipet 2 mL of this solution into a 50-mL volumetric flask, dilute with pH 7 buffer solution to volume, and mix. The molar absorptivity of this solution, at 239 nm, is not less than 9000.

Phenylglycine (d(

)-2-Phenylglycine),

(C6H5CH(NH2)COOH)—151.17

[875-74-1]—Use a suitable grade.

Phenylhydrazine,

C6H5NHNH2—108.14

[100-63-0]—A colorless, or slightly yellowish, highly refractive liquid. [Note—Protect from light, and distill under reduced pressure shortly prior to use. ]

Congealing temperature

651

not below 16

Insoluble matter— Shake 1 mL with 20 mL of diluted acetic acid: the resulting solution is clear or practically so.

Residue on ignition (Reagent test)— Ignite 1 mL with 0.5 mL of sulfuric acid: the residue weighs not more than 1 mg (0.1%).

Phenylhydrazine Hydrochloride,

C6H5NHNH2·HCl—144.60

[59-88-1]—White or yellowish crystals or powder. Soluble in water and in alcohol. Store in tight containers, protected from light. Use a suitable grade with a content of not less than 99%.

Phenylmethylsulfonyl Fluoride,

C7H7FO2S—174.2

[329-98-6]—White to faint yellow powder. Use a suitable grade.

[Note—A suitable grade is available from Sigma-Aldrich, www.sigma-aldrich.com. ]

3-Phenylphenol (m-Phenylphenol),

C6H5C6H4OH—170.21

[580-51-8]—White to off-white, crystalline powder.

Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography

) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 30-m capillary column coated with G1; the injection port temperature is maintained at 250

; the column temperature is maintained at 150

and programmed to rise 15

per minute to 250

; and the detector temperature is maintained at 310

. The area of the 3-phenylphenol peak is not less than 98% of the total peak area.

: between 76

and 79

Phloroglucinol,

C6H3(OH)3·2H2O—162.14

[6099-90-7]—White or yellowish-white crystals or a crystalline powder. Soluble in alcohol and in ether; slightly soluble in water.

Insoluble in alcohol— Dissolve 1 g in 20 mL of alcohol: a clear and complete solution results.

Melting range, Class Ia

: between 215

and 219

Residue on ignition (Reagent test)— Ignite 1 g with 0.5 mL of sulfuric acid: the residue weighs not more than 1 mg (0.1%).

Diresorcinol— Heat to boiling a solution of 100 mg in 10 mL of acetic anhydride, cool the solution, and superimpose it upon 10 mL of sulfuric acid: no violet color appears at the zone of contact of the liquids.

Phloxine B (Acid red 92; Eosin 10B; 2',4',5',7'-tetrabromo-4,5,6,7-tetrachlorofluorescein disodium salt)

C20H2Br4Cl4Na2O5—829.63

[18472-87-2]—Use a suitable grade with a dye content of not less than 80%, certified by the Biological Stain Commission.

Phosphatase Enzyme, Alkaline —Use a suitable grade from intestinal origin.

[Note—A suitable grade is available from Worthington Biochemical Corp., www.worthington-biochem.com. ]

Phosphatic Enzyme —An enzyme preparation of microbial origin, high in both phosphatase and amylase activity, the former being the property that renders it suitable for use in the liberation of thiamine from its orthophosphate and pyrophosphate esters. Light cream-colored or slightly gray powder. Freely soluble in water. It hydrolyzes 300 times its weight of starch in 30 minutes.

Amylase activity— Place in a test tube 5 mL of a 1 in 50 solution of soluble starch in 0.2 M, pH 5 sodium acetate buffer (containing 1.6 g of anhydrous sodium acetate in each L and sufficient glacial acetic acid to adjust to a pH of 5), and add 4 mL of water. Mix, and place in a water bath at 40

. Add 1 mL of a solution containing 0.3 mg of the phosphatic enzyme, mix, and note the exact time. After 30 minutes remove 1.0 mL of the mixture, and add it to 5.0 mL of 0.0005 N iodine in a 20- × 150-mm test tube: a clear, red color results.

Phosphomolybdic Acid,

approximately 20MoO3·P2O5·51H2O—3939.49

[51429-74-4]—Use ACS reagent grade.

Phosphoric Acid,

H3PO4—98.00

[7664-38-2]—Use ACS reagent grade.

Phosphorous Acid (Phosphonic Acid),

H3O3P—82.00

[13598-36-2]—Use a suitable grade with a content of not less than 99%.

Phosphorus, Red,

P—At. Wt. 30.97376—A dark red powder. Insoluble in water and in dilute acids; soluble in dehydrated alcohol.

Yellow phosphorus— Shake 20 g with 75 mL of carbon disulfide in a glass-stoppered vessel, and allow to stand in the dark overnight. Filter, and wash the residue with carbon disulfide until the filtrate, collected in a graduated cylinder, measures 100 mL. Evaporate the solvent to 10 mL by immersing the cylinder in hot water. Dip a strip of cupric sulfate test paper in the remaining solvent: no more color is produced than in a similar strip dipped into 10 mL of solution in carbon disulfide containing 3 mg of yellow phosphorus (0.015% as P).

Soluble substances— Digest 2 g with 30 mL of acetic acid on a steam bath for 15 minutes. Cool, dilute with water to 40 mL, and filter. Evaporate 20 mL of the filtrate on a steam bath, and dry at 105

for 2 hours: the residue weighs not more than 6 mg (0.6%).

Phosphorus Pentoxide (Phosphoric Anhydride),

P2O5—141.94

[1314-56-3]—Use ACS reagent grade.

Phosphotungstic Acid,

approximately 24WO3·P2O5·51H2O—6624.84—White or yellowish-green crystals or a crystalline powder. Soluble in water, in alcohol, and in ether.

Insoluble matter (Reagent test):

not more than 1 mg, from 5 g (0.02%).

Chloride (Reagent test)— One g shows not more than 0.3 mg of Cl (0.03%).

Nitrate— Dissolve 500 mg in 10 mL of water, and add about 10 mg of sodium chloride, 0.1 mL of indigo carmine TS, and 10 mL of sulfuric acid: the blue color does not disappear within 1 minute (about 0.01%).

Sulfate (Reagent test, Method I )— A 500-mg portion shows not more than 0.1 mg of SO4 (0.02%).

o-Phthalaldehyde (Phthalic Dicarboxaldehyde),

C6H4(CHO)2—134.13

[643-79-8]—Use a suitable grade.

Phthalazine,

C8H6N2—130.15

[253-52-1]—Yellow to tan crystals.

: between 89

and 92

Phthalic Acid,

C8H6O4—166.13

[88-99-3]—Use ACS reagent grade.

Phthalic Anhydride,

C8H4O3—148.12

[85-44-9]—Use ACS reagent grade.

Phthalimide,

C8H5NO2—147.13

[85-41-6]—White powder.

Assay—

Mobile phase— Prepare a mixture of isooctane and methyl-tert-butyl ether (88:12).

Procedure— Inject about 20 µL into a suitable liquid chromatograph (see Chromatography

) equipped with a 230-nm detector and a 4.6-mm × 15-cm column that contains packing L3. The flow rate is about 2 mL per minute. The area of the C8H5NO2 peak is not less than 99% of the total peak area.

: between 233

and 235

, with decomposition.

2-Picoline,

C6H7N—93.13

[109-06-8]—Colorless to yellowish liquid.

Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography

) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2-mm × 2-m glass column packed with 20% liquid phase G16 on 80- to 100-mesh support S1C; the injection port temperature is maintained at 140

; the detector temperature is maintained at 300

; the column temperature is maintained at 90

and programmed to rise 3

per minute to 140

. The area of the C6H7N peak is not less than 98% of the total peak area.

: 1.500 ± 0.002 at 20

Picric Acid (2,4,6-Trinitrophenol; Trinitrophenol),

C6H2(OH)(NO2)3-1,2,4,6—229.10

[88-89-1]—Use ACS reagent grade.

Picrolonic Acid (3-Methyl-4-nitro-1-(p-nitrophenyl)-5-pyrazolone),

C10H8N4O5—264.19

[550-74-3]—Yellow to brownish-yellow, crystalline powder. Slightly soluble in water; soluble in alcohol, in chloroform, in ether, in benzene, and in solutions of alkali hydroxides.

: between 115

and 117

Residue on ignition (Reagent test):

negligible, from 200 mg.

Sensitiveness— Dissolve 25 mg in 10 mL of warm water containing 0.1 mL of glacial acetic acid, and filter the solution, if necessary. Dissolve 100 mg of calcium chloride in 250 mL of water, and mix. Heat 1 mL of the calcium chloride solution in a test tube to about 60

, then add to it 1 mL of the picrolonic acid solution: a bulky precipitate forms in 5 minutes or less.

Pipemidic Acid (8-Ethyl-3,8-dihydro-5-oxo-2-(1-piperazinyl)pyrido[2,3-d]-pyrimidine-6-carboxylic acid),

C14H17N5O3—303.3

[51940-44-4]—Use a suitable grade.

Piperazine (Diethylenediamine),

C4H10N2·6H2O—194.23—Use a suitable grade.

Piperidine,

C5H11N—85.15

[110-89-4]—Colorless liquid. Miscible with water and with alcohol. Specific gravity: about 0.860.

Congealing range

651

: between 12

and 15

Boiling range (Reagent test)— Not less than 95% distills between 104

and 106

Refractive index: about 1.454.

Platinic Chloride (Chloroplatinic Acid),

H2PtCl6·6H2O—517.90

[18497-13-7]—Use ACS reagent grade Chloroplatinic Acid.

Polydimethylsiloxane, viscosity 0.65 centistokes (Hexamethyldisiloxane),

(CH3)3SiOSi(CH3)3—162.38

[107-46-0]—Liquid. Freezes at about 0

about 1.3770.

about 0.760.

Polyethylene Glycol 200,

H(OCH2CH2)nOH in which the average value of n is 4—average molecular weight 200

[25322-68-3]—Clear, colorless or almost colorless, viscous, hygroscopic liquid. Very soluble in acetone and in alcohol; practically insoluble in ether and in fatty oils. Use a suitable grade.

Viscosity—Capillary Methods

1.4590 at 20

Density:

1.127 at 25

Viscosity:

4.3 centistokes at 98.9

Polyethylene Glycol 600

[25322-68-3]—A clear, practically colorless, viscous liquid condensation polymer represented by H(OCH2CH2)nOH, in which n varies from 12 to 14. Its average molecular weight is about 600.

It meets the requirements of all of the tests under Polyethylene Glycol (NF monograph) except Limit of ethylene glycol and diethylene glycol.

Change to read:

Polyethylene Glycol 20,000

[25322-68-3]—Molecular weight range: 15,000–20,000. Hard, white, waxy solid, usually supplied in flake form. Soluble in water with subsequent gel formation.

911

, Viscosity of 25% solution

(CN 1-May-2015)

— Add 50.0 g of test specimen to a 250-mL wide-mouth, screw-cap jar containing 150.0 g of water. Attach the cap securely to the jar, and roll on a mechanical roller until the test specimen is completely dissolved, in 2 to 4 hours. Allow the solution to stand until all air bubbles have disappeared. Another 2 to 4 hours may be required. Adjust the temperature of the solution to 37.8 ± 0.1

, and determine the kinematic viscosity on a suitable viscometer of the Ubbelohde type. The viscosity is not less than 100 centistokes.

791

between 6.5 and 8.0 in a solution (1 in 20). [Note—A five-fold dilution of the test solution prepared for the Viscosity of 25% solution test may be used. ]

Residue on ignition

281

not more than 0.7%, the use of sulfuric acid being omitted.

Polyoxyethylene 10 Lauryl Ether (Decaethylene Glycol Monododecyl Ether),

C32H66O11—626.86

[6540-99-4]—Use a suitable grade. [Note—A suitable grade is available as catalog number P9769 at http://www.sigma.com. ]

Polyoxyethylene (23) Lauryl Ether (Brij-35)— Use a suitable grade.

[Note—A suitable grade is available commercially as “Brij-35.” ]

Polyoxyethylene (20) Sorbitan Monolaurate

[9005-64-5]—Viscous, light yellow to yellow-green liquid. Use a suitable grade.

Polysaccharide Molecular Weight Standards —Polymaltotriose polymers of different weight-average molecular weight, MW, values ranging from 5,000 to 400,000 Da.

[Note—A suitable set is available from Shodex (www.shodex.com) as Kit P-82. ]

Polystyrene Cation–Exchange Resin —See Cation–Exchange Resin, Polystyrene.

Polytef —Use Poly(tetrafluoroethylene).

Polyvinyl Alcohol,

(C2H4O)n

[9002-89-5]—White powder. Soluble in water; insoluble in organic solvents.

791

between 5.0 and 8.0, in a solution (1 in 25).

Loss on drying— Dry it at 110

to constant weight: it loses not more than 5% of its weight.

Residue on ignition:

not more than 0.75%.

[Note—Suitable grades are available as catalog number U 232, from J.T. Baker Chemical Co., www.jtbaker.com. ]

Potassium Acetate,

KC2H3O2—98.14

[127-08-2]—Use ACS reagent grade.

Potassium Alum —Use Potassium Alum [see Potassium Alum (USP monograph)].

Potassium Arsenate Monobasic,

KH2AsO4—180.03

[7784-41-0]—Use a suitable grade with a content of NLT 98%.

Potassium Bicarbonate,

KHCO3—100.12

[298-14-6]—Use ACS reagent grade.

Potassium Biphosphate —See Potassium Phosphate, Monobasic.

Potassium Biphthalate (Acid Potassium Phthalate; Phthalic Acid Monopotassium Salt; Potassium Hydrogen Phthalate Acidimetric Standard),

KHC6H4(COO)2—204.22

[877-24-7]—Use ACS reagent grade Potassium Hydrogen Phthalate, Acidimetric Standard.

Potassium Bisulfate,

KHSO4—136.17

[7646-93-7]—Fused, white, deliquescent masses or granules. Very soluble in water. When ignited, it evolves SO3 and H2O, changing first to potassium pyrosulfate, then to sulfate.

Acidity— Dissolve 4 g, accurately weighed, in 50 mL of water, add phenolphthalein TS, and titrate with 1 N alkali: it contains between 34% and 36%, calculated as H2SO4.

Insoluble matter and ammonium hydroxide precipitate— Dissolve 10 g in 100 mL of water, add methyl red TS, render slightly alkaline with ammonia TS, boil for 1 minute, and digest on a steam bath for 1 hour. Pass through a tared filtering crucible, wash thoroughly, and dry at 105

for 2 hours: the precipitate weighs not more than 1 mg (0.01%).

For the following tests, prepare a Test solution as follows. Dissolve 6 g in 45 mL of water, add 2 mL of hydrochloric acid, boil gently for 10 minutes, cool, and dilute with water to 60 mL.

Heavy metals (Reagent test)— To 30 mL of Test solution add phenolphthalein TS, and neutralize with ammonia TS. Add 0.5 mL of glacial acetic acid, dilute with water to 40 mL, and add 10 mL of hydrogen sulfide TS: any brown color produced is not darker than that of a control containing 10 mL of Test solution and 0.02 mg of added Pb (0.001%).

Iron

241

— To 5 mL of Test solution add 2 mL of hydrochloric acid, and dilute with water to 47 mL: the solution shows not more than 0.01 mg of Fe (0.002%).

Potassium Bromate,

KBrO3—167.00

[7758-01-2]—Use ACS reagent grade.

Potassium Bromide,

KBr—119.00

[7758-02-3]—Use ACS reagent grade.

Potassium Carbonate —See Potassium Carbonate, Anhydrous.

Potassium Carbonate, Anhydrous,

K2CO3—138.21

[584-08-7]—Use ACS reagent grade.

Potassium Chlorate,

KClO3—122.55

[3811-04-9]—Use ACS reagent grade.

Potassium Chloride,

KCl—74.55

[7447-40-7]—Use ACS reagent grade.

Potassium Chloroplatinate,

K2PtCl6—485.99—Heavy, yellow powder. Soluble in hydrochloric acid and in nitric acid.

Assay— Accurately weigh about 300 mg, transfer to a 600-mL beaker, add 20 mL of hydrochloric acid, and heat gently if necessary to achieve complete solution. Add zinc granules, slowly, until no more dissolves, then add 2 mL of hydrochloric acid, and digest for 1 hour on a steam bath to coagulate the reduced platinum. Add more acid, if necessary, to ensure that all of the zinc has dissolved. Filter through paper, rinsing the beaker with diluted hydrochloric acid until all of the precipitate is transferred to the filter, then wash with several small portions of water. Ignite the filter in a tared crucible at 800 ± 25

to constant weight. Each mg of residue is equivalent to 1.0 mg of platinum. Not less than 40% is found.

Potassium Chromate,

K2CrO4—194.19

[7789-00-6]—Use ACS reagent grade.

Potassium Cyanide,

KCN—65.12

[151-50-8]—Use ACS reagent grade.

Potassium Dichromate,

K2Cr2O7—294.18

[7778-50-9]—Use ACS reagent grade.

[Note—Potassium dichromate of a quality suitable as a primary standard is available from the National Institute of Standards and Technology, Washington, DC, www.nist.gov, as standard sample No. 136. ]

Potassium Ferricyanide,

K3Fe(CN)6—329.24

[13746-66-2]—Use ACS reagent grade.

Potassium Ferrocyanide,

K4Fe(CN)6·3H2O—422.39

[14459-95-1]—Use ACS reagent grade.

Potassium Hyaluronate —White to cream-colored powder. Freely soluble in water. Store in a tight container, in a refrigerator.

Inhibitor content— Prepare as directed in the Assay under Hyaluronidase for Injection (USP monograph) a quantity of Standard solution containing 1 USP Hyaluronidase Unit in each mL, and a similar quantity of acetate-buffered Standard solution using as the solvent 0.1 M, pH 6 sodium acetate buffer (prepared by diluting the 0.2 M buffer prepared as directed below with an equal volume of water). Prepare from the potassium hyaluronate under test 10 mL of Potassium hyaluronate stock solution, and dilute 2 mL of it with the specified Phosphate buffer solution to make a Hyaluronate solution. In the same way, and concurrently, dilute a second 2-mL portion of the stock solution with 0.2 M, pH 6 sodium acetate buffer (containing 16.4 g of anhydrous sodium acetate and 0.45 mL of glacial acetic acid in each 1000 mL).

Place 0.50-mL portions of the Hyaluronate solution in each of four 16- × 100-mm test tubes, and place 0.50-mL portions of the acetate-buffered Hyaluronate solution in two similar tubes. To two of the four tubes containing Hyaluronate solution add 0.50 mL of Diluent for hyaluronidase solutions, prepared as directed in the Assay under Hyaluronidase for Injection (USP monograph). To the remaining two tubes, on a rigid schedule, at 30-second intervals, add 0.50 mL of Standard solution. Similarly, to the two tubes containing acetate-buffered Hyaluronate solution add at 30-second intervals 0.50-mL portions of acetate-buffered Standard solution. Then proceed as directed in the second paragraph for Procedure, beginning with “Mix the contents,” as far as “Plot the average.” The reduction in absorbance of acetate-buffered Hyaluronate solution is not less than 25% of that observed in the Hyaluronate solution.

Turbidity production— The average absorbance of the solutions in the two tubes containing Hyaluronate solution and Diluent for hyaluronidase solutions prepared in the test for Inhibitor content is not less than 0.26 at a wavelength of 640 nm in a suitable spectrophotometer using a 1-cm cell.

Potassium Hydrogen Sulfate,

KHSO4—136.17—White crystals. Soluble in water.

Melting point

about 197

Potassium Hydroxide,

KOH—56.11

[1310-58-3]—Use ACS reagent grade.

Potassium Iodate,

KIO3—214.00

[7758-05-6]—Use ACS reagent grade.

Potassium Iodide,

KI—166.00

[7681-11-0]—Use ACS reagent grade.

Potassium Metabisulfite (Potassium Disulfite; Potassium Pyrosulfite),

K2S2O5—222.32

[16731-55-8]—Use a suitable grade with a content of not less than 98%.

Potassium Nitrate,

KNO3—101.10

[7757-79-1]—Use ACS reagent grade.

Potassium Nitrite,

KNO2—85.10

[7758-09-0]—Use ACS reagent grade.

Potassium Perchlorate,

KClO4—138.55

[7778-74-7]—Use ACS reagent grade.

Potassium Periodate (Potassium meta-Periodate),

KIO4—230.00

[7790-21-8]—Use ACS reagent grade.

Potassium Permanganate,

KMnO4—158.03

[7722-64-7]—Use ACS reagent grade.

Potassium Persulfate,

K2S2O8—270.32

[7727-21-1]—Use ACS reagent grade Potassium Peroxydisulfate.

Potassium Phosphate, Dibasic (Dipotassium Hydrogen Phosphate; Dipotassium Phosphate),

K2HPO4—174.18

[7758-11-4]—Use ACS reagent grade.

Potassium Phosphate, Dibasic, Trihydrate (Dipotassium Hydrogen Phosphate Trihydrate; Dipotassium Phosphate),

K2HPO4·3H2O—228.22

[16788-57-1]—Use a suitable grade with a content of NLT 99.0%.

Potassium Phosphate, Monobasic (Potassium Biphosphate; Potassium Dihydrogen Phosphate),

KH2PO4—136.09

[7778-77-0]—Use ACS reagent grade.

[Note—Certified Potassium Dihydrogen Phosphate is available from the National Institute of Standards and Technology, Washington, DC, www.nist.gov, as standard sample No. 186. ]

Potassium Phosphate, Tribasic,

K3PO4—212.27

[7778-53-2]—Deliquescent, orthorhombic crystals. Use ACS reagent grade.

Potassium Pyroantimonate (Potassium hexahydroxyantimonate), KSb(OH)6 —262.90

[12208-13-8]—White crystals or a white, crystalline powder. Sparingly soluble in water. Use a suitable grade.

Potassium Pyrophosphate,

K4P2O7—330.34

[7320-34-5]—Colorless, deliquescent granules. Freely soluble in water; insoluble in alcohol.

Potassium Pyrosulfate

[7790-62-7]—Usually available as a mixture of potassium pyrosulfate (K2S2O7) and potassium bisulfate (KHSO4). Use ACS reagent grade.

Potassium Sodium Tartrate,

KNaC4H4O6·4H2O—282.22

[6381-59-5]—Use ACS reagent grade.

Potassium Sulfate,

K2SO4—174.26

[7778-80-5]—Use ACS reagent grade.

Potassium Tellurite (Potassium Tellurate IV),

K2TeO3—253.79

[7790-58-1]—White, granular powder. Soluble in water. Its solution is alkaline.

Assay— Weigh accurately about 120 mg, transfer to a beaker, and dissolve in a mixture of 10 mL of nitric acid, 10 mL of sulfuric acid, and 25 mL of water. Heat to boiling, and boil until copious fumes of sulfur trioxide are evolved. Cool, cautiously add 100 mL of water, heat to boiling, add 6 g of sodium fluoride, and titrate the hot solution with 0.1 N potassium permanganate VS. Each mL of 0.1 N potassium permanganate is equivalent to 12.69 mg of K2TeO3. Not less than 98% is found.

Chloride (Reagent test)— One g shows not more than 0.1 mg of Cl (0.01%).

Potassium Thiocyanate,

KSCN—97.18

[333-20-0]—Use ACS reagent grade.

Potato Starch —See Starch, Potato.

Pregnenolone Acetate (3

-Acetoxy-5-pregnen-20-one, 5-Pregnen-3

-ol-20-one Acetate),

C23H34O3—358.51

[1778-02-5]—Use a suitable grade with a content of NLT 99%.

Propionaldehyde,

C3H6O—58.08

[123-38-6]—Use a suitable grade.

Propionic Anhydride,

C6H10O3—130.14

[123-62-6]—Colorless liquid. Is decomposed by water. Soluble in methanol, in alcohol, in ether, and in chloroform.

Assay— Accurately weigh about 350 mg into a tared, glass-stoppered flask containing 50 mL of dimethylformamide previously neutralized to the thymol blue endpoint with 0.1 N sodium methoxide in methanol VS. Titrate with 0.1 N sodium methoxide in methanol VS to the thymol blue endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium methoxide is equivalent to 13.014 mg of C6H10O3. Not less than 97.0% is found.

: between 1.4035 and 1.4045 at 20

Propiophenone,

C9H10O—134.18

[93-55-0]—Use a suitable grade.

iso-Propyl Alcohol —See Isopropyl Alcohol.

n-Propyl Alcohol (1-Propanol),

CH3CH2CH2OH—60.10

[71-23-8]—Use ACS reagent grade.

Propylamine Hydrochloride (1-Propanamine hydrochloride; n-Propylamine hydrochloride),

C3H9N·HCl—95.57

[556-53-6]—Use a suitable grade with a content of not less than 99%.

Protein Molecular Weight Standard— Also known as protein molecular weight markers (for SDS-PAGE) and consists of a mixture of several proteins of well-defined molecular weights. The products are generally available in a suitable buffer containing a suitable reducing agent (generally, 100 mM DTT), a preservative (for example, sodium azide), and 50% glycerol to prevent freezing. Use a suitable grade. Store at –20

Protein Standard Solution (8 g/dL) —A solution containing 5 g of Albumin Human and 3 g of human gamma globulin per dL.

[Note—A suitable grade is available as Protein Standard Solution, catalog number 540-10, from Sigma-Aldrich, www.sigma-aldrich.com. ]

Protocatechuic Acid (3,4-Dihydroxybenzoic acid),

C7H6O4—154.12

[99-50-3]—Use a suitable grade.

Pullulanase (Amylopectin-6-gluconohydrolase)

[9075-68-7]—An enzyme obtained from Kleibsiella pneumoniae. It contains not less than 30 units per mg of protein. One unit defined for enzymatic activity will liberate 1.0 µmol of maltotriose (measured as glucose) from pullulan per minute at pH 5.0 at 30

. It can be suspended in 3.2 M ammonium sulfate solution, pH 6.2.

Measurement of relative pullulanase activity—

Determination of pullulanase activity—

Substrate— Dissolve pullulan1

1 A suitable supplier for pullulan is www.hayashibara-intl.com.

in water to make a 1.25% (w/v) solution. [Note—Add pullulan to the water. Clumping will occur if water is added to pullulan. ]

Buffer solution A, pH 5.0— Add 0.1 M disodium phosphate (27 g of dibasic sodium phosphate in each L of the solution) to 0.1 M citric acid (21 g of citric acid in each L of the solution) to adjust pH to 5.0.

Buffer solution B, pH 6.0— Add diluted acetic acid to 1 M sodium acetate (136 g of sodium acetate in each L of solution) to adjust the pH to 6.0. Dilute with water to prepare the final buffer solution as 0.01 M acetic acid buffer, pH 6.0.

Somogyi reagent— Add 54 g of disodium phosphate heptahydrate or 28 g of anhydrous disodium hydrogen phosphate and 40 g of potassium sodium tartrate to about 650 mL of water or about 700 mL for anhydrous disodium hydrogen phosphate. Add 100 mL of 1 N sodium hydroxide to this solution and mix. Add 80 mL of 10% cupric sulfate to the solution, and mix. Heat until any solid is completely dissolved. Add 180 g of anhydrous sodium sulfate to the solution and adjust the volume to 1 L. Allow the solution to stand at room temperature for 1 or 2 days to let insoluble matter precipitate. Filter the solution with standard filter paper, and keep the solution in a brown bottle with a ground-glass stopper.

Nelson reagent— Dissolve 50 g of ammonium molybdate in 900 mL of water. Add 42 g of sulfuric acid, and mix. Dissolve 6 g of sodium arsenate or 3.6 g of monobasic potassium arsenate in 50 g of water. Allow the solution to stand in a brown bottle with a ground-glass stopper at 37

for 1 or 2 days.

Glucose standard solution— Dry anhydrous glucose crystals under less than 50-mm Hg at 60

for 5 hours, and calculate the water content. Transfer 10.00 g of dried glucose to a 1-L volumetric flask, dissolve in and dilute with water to volume, and mix. Transfer 10.0 mL to a 1-L volumetric flask and dilute to volume with water. Each mL contains 100 µg of glucose.

Pullulanase diluent— Dilute pullulanase with Buffer solution B, pH 6.0 to prepare a solution having the enzyme activity of about 0.2 units per mL. [Note—The measurement range is between 0.1 and 0.4 units per mL. ] Record the dilution factor (FPD). This diluent is used as a diluted enzyme solution.

Procedure— Transfer 4 mL of Substrate to a test tube and add 0.5 mL of Buffer solution A, pH 5.0, mix, and incubate at 30

. Add 0.5 mL of Pullulanase diluent, and mix thoroughly. After 30 seconds, transfer 1 mL of this solution to a test tube labeled as “Pullulan test solution 1”, and add 2 mL of Somogyi reagent, and mix. After 30 minutes and 30 seconds, transfer 1 mL of the mixture of Substrate and Pullulanase diluent to a second test tube labeled as “Pullulan test solution 2”, add 2 mL of Somogyi reagent, and mix. In a third test tube labeled as “Standard blank”, mix 2 mL of Somogyi reagent and 1 mL of water. In a fourth test tube labeled as “Glucose standard solution”, mix 2 mL of Somogyi reagent and 1 mL of Glucose standard solution, and add 1 mL of water. Incubate the fourth test tube in a boiling water bath for exactly 10 minutes. Remove the tube and allow it to cool in cold running water. Add 2 mL of Nelson reagent, mix well, and allow the solution to stand for at least 15 minutes. Add 5 mL of water to each of the four test tubes, and mix thoroughly. Determine the absorbance at 520 nm of the Standard blank, Ablank, of the Glucose standard solution, AStd, of the Pullulan test solution 1, A0, and of the Pullulan test solution 2, A30, using water as the blank. One unit is defined as the enzymatic activity that produces 1 µmol of maltotriose (measured as glucose) from pullulan per minute. Calculate the pullulanase activity, PA, in units per mL, using the formula:

PA = [(A30

A0)/(AStd

Ablank)] × 0.185 × FPD

Measurement of protein amount (measured as albuminoid amount) for the calculation of specific activity—

Reagent A— Prepare a solution having known concentrations of about 0.1 N sodium hydroxide and about 0.2 M sodium carbonate.

Reagent B— Transfer 0.5 g of cupric sulfate and 1.0 g of sodium citrate dihydrate to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.

Lowry solution— Mix Reagent A and Reagent B at the proportion of 50:1.

Diluted Folin-Ciocalteu's phenol reagent (for albuminoid quantification)— Prepare a two-fold dilution of 2 N Folin-Ciocalteu's phenol reagent commercially available or prepare a solution by making an appropriate dilution from Folin-Ciocalteu Phenol TS (see Method 2 in Biotechnology-Derived Articles—Total Protein Assay

1057

Bovine serum albumin standard stock solution— Transfer 0.05 g of bovine serum albumin to a 500-mL volumetric flask, dissolve in and dilute with water to volume, and mix. It contains 100 µg of bovine serum albumin per mL.

Standard solutions— Using appropriate dilutions of Bovine serum albumin standard stock solution in water, prepare five Standard solutions having concentration equally spaced between 5 and 100 µg of bovine serum albumin per mL.

Test solution— Dilute pullulanase with Buffer solution B, pH 6.0 in order to obtain a solution having a concentration between 60 and 70 µg of albuminoid per mL. [Note—Water can be used as diluent. ] Record the dilution factor, FTS.

Blank solution— Use water.

Procedure— To 0.3 mL in separate tubes of the Standard solutions, the Test solution, and the Blank solution, add 3 mL of Lowry solution, and mix. Allow to incubate at room temperature for 10 minutes. Add 0.3 mL of Diluted Folin-Ciocalteu's phenol reagent to each tube, mix immediately, and allow to stand at room temperature for 60 minutes. Determine the absorbances of the Standard solutions and the Test solution at the wavelength of maximum absorbance at about 750 nm, using the Blank solution as the blank.

Calculation— [Note—The relationship of absorbance to protein concentration is nonlinear; however, if the standard curve concentration range is sufficiently small, it will approach linearity. ] Using linear regression method, plot the absorbances of the Standard solutions versus the protein (bovine serum albumin) concentrations, in µg per mL, and determine the best fit curve. Using the plot, determine the concentration, Calbuminoid, in µg per mL, of protein (albuminoid amount) in the Test solution. Calculate the albuminoid concentration, in mg per mL, in the pullulanase taken by the formula:

Cprotein = (Calbuminoid × FTS)/1000

Calculate the specific activity, SA, in units per mg, of pullulanase using the formula:

SA = PA/Cprotein

Pumice —A substance of volcanic origin consisting chiefly of complex silicates of aluminum and alkali metals. Occurs as very light, hard, rough, porous, gray masses, or as a gray-colored powder. Is insoluble in water and is not attacked by diluted acids.

Acid- and water-soluble substances— Boil 2.0 g of powdered pumice with 50 mL of diluted hydrochloric acid under a reflux condenser for 30 minutes. Cool, and filter. To half of the filtrate add 5 drops of sulfuric acid, evaporate to dryness, ignite, and weigh: the residue weighs not more than 60 mg (6.0%).

Purine,

C5H4N4—120.11

[120-73-0]—White to off-white powder.

between 214

and 217

A single spot is exhibited when it is examined by thin-layer chromatography, with the use of plates coated with chromatographic silica gel mixture and a developing system consisting of butyl alcohol, water, and glacial acetic acid (60:25:15).

Putrescine Dihydrochloride,

C4H12N2·2HCl—161.07

[333-93-7]—White, crystalline powder. Use a suitable grade.

Pyrazole,

C3H4N2

[288-13-1]—White to pale yellow crystals or crystalline powder. Soluble in water, in alcohol, and in ether.

between 67

and 71

Pyrene,

C16H10—202.25

[129-00-0]—White to light yellow crystals.

Assay— Transfer about 9 mg, accurately weighed, to a 100-mL volumetric flask, dissolve in methanol, dilute with methanol to volume, and mix. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, dilute with methanol to volume, and mix. Using a suitable spectrophotometer, 1-cm cells, and methanol as the blank, record the absorbance of the solution at the wavelength of maximum absorbance at about 238 nm. From the observed absorbance, calculate the absorptivity (see Spectrophotometry and Light-scattering

851

): the absorptivity is not less than 432.9, corresponding to not less than 98% of C16H10.

between 149

and 153

over a 2

range.

Pyridine,

C5H5N—79.10

[110-86-1]—Use ACS reagent grade.

Pyridine, Dried

[110-86-1]—Use ACS reagent grade.

Pyridoxal Hydrochloride,

C8H9NO3·HCl—203.62

[65-22-5]—White to slightly yellow crystals or crystalline powder. Gradually darkens on exposure to air or sunlight. One g dissolves in about 2 mL of water and in about 25 mL of alcohol. Insoluble in acetone, in chloroform, and in ether. Its solutions are acid (pH about 3).

: between 171

and 175

with some decomposition.

Residue on ignition (Reagent test): not more than 0.1%.

— Dry it at 105

for 2 hours: it loses not more than 0.5% of its weight.

Nitrogen content (Reagent test)— Determine by the Kjeldahl method, using a test specimen previously dried at 105

for 2 hours: between 6.7% and 7.1% of N is found.

Chloride content— Accurately weigh about 500 mg, previously dried at 105

for 2 hours, and dissolve in 50 mL of water. Add 3 mL of nitric acid and 50.0 mL of 0.1 N silver nitrate VS, then add 5 mL of nitrobenzene, shake for about 2 minutes, add ferric ammonium sulfate TS, and titrate the excess silver nitrate with 0.1 N ammonium thiocyanate VS: each mL of 0.1 N silver nitrate is equivalent to 3.545 mg of Cl. Between 17.2% and 17.7% is found.

Pyridoxal 5-Phosphate,

4-CHOC5HN-2-CH3, 3-OH, 5-CH2PO4H2·H2O—265.16

[41468-25-1]—Light yellow powder. Use a suitable grade.

Pyridoxamine Dihydrochloride,

C8H12N2O2·2HCl—241.11

[524-36-7]—White to slightly yellow crystals or crystalline powder. Gradually darkens on exposure to air or sunlight. One g dissolves in about 1 mL of water and in about 60 mL of alcohol. Insoluble in chloroform and in ether. Its solutions are acid.

: between 225

and 230

, with some decomposition.

Residue on ignition (Reagent test): not more than 0.15%.

— Dry it at 105

for 2 hours: it loses not more than 0.5% of its weight.

Nitrogen content (Reagent test)— Determine by the Kjeldahl method, using a test specimen previously dried at 105

for 2 hours: between 11.3% and 11.8% of N is found.

Chloride content— Determine as directed in the test for Chloride content under Pyridoxal Hydrochloride: between 29.1% and 29.6% of Cl is found.

1-(2-Pyridylazo)-2-naphthol,

C15H11N3O—249.27

[85-85-8]—Stable, orange-red crystals. Soluble in alcohol and in hot solutions of dilute alkalies; slightly soluble in water.

: between 140

and 142

Sensitiveness— Add 0.1 mL of a 1 in 1000 solution of it in alcohol to a mixture of 10 mL of water and 1 mL of a buffer solution prepared by mixing 80 mL of 0.2 M acetic acid and 20 mL of sodium acetate solution (8.2 in 100), and mix. To this solution add 1 mL of a mixture of 1 mL of cupric sulfate TS and 2 mL of water, and mix: the color changes from yellow to red.

4-(2-Pyridylazo)resorcinol (PAR),

C11H9N3O2, free acid; C11H8N3NaO2, monosodium salt—215.21,

free acid—237.21,

monosodium salt

[1141-59-9, free acid; 16593-81-0, monosodium salt]—Use ACS reagent grade.

3-(2-Pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5¢,5¢¢-disulfonic Acid, Disodium Salt (3-(2-Pyridyl)-5,6-bis(5-sulfo-2-furyl)-1,2,4-triazine, Disodium Salt Hydrate),

C16H8N4Na2O8S2—494.37

[79551-14-7]—Use a suitable grade.

[Note—A suitable grade is available as product number P4272 from Sigma-Aldrich, 1-800-558-9160; www.sigma-aldrich.com. ]

Pyrogallol,

C6H3(OH)3—126.11

[87-66-1]—Use ACS reagent grade.

Pyrrole,

C4H5N—67.09

[109-97-7]—Clear liquid, colorless when freshly distilled, becoming yellow in a few days. Specific gravity: about 0.94. Insoluble in water; soluble in alcohol, in benzene, and in ether.

Boiling range (Reagent test)— Not less than 90% distills between 128

and 132

Pyruvic Acid,

CH3COCOOH—88.06

[127-17-3]—Colorless to light yellow liquid. Miscible with water, with alcohol, and with ether.