Earth, Chromatographic, Silanized, Acid-Base Washed
—Use a suitable grade.
[Note—A suitable chromatographic grade is “Gas-Chrom Q,” available from Alltech, www.alltechweb.com. ]
Add the following:
[
USP38
Edetate Disodium
(Disodium Ethylenediaminetetraacetate)
C10H14N2O8Na2·2H2O—372.24—Use ACS reagent grade (Ethylenedinitrilo)tetraacetic Acid Disodium Salt Dihydrate.
C10H14N2O8Na2·2H2O—372.24—Use ACS reagent grade (Ethylenedinitrilo)tetraacetic Acid Disodium Salt Dihydrate.
n-Eicosane,
C20H42—282.55 [112-95-8]—White, crystalline solid.
C20H42—282.55 [112-95-8]—White, crystalline solid.
Melting range 
741
:
between 37
and 39.
741 :
between 37 and 39.
Eicosanol
[629-96-9]—Use a suitable grade.
[629-96-9]—Use a suitable grade.
Eosin Y (Eosin Yellowish Y)
(Certified Biological Eosin Y; Sodium Tetrabromofluorescein),
C20H6Br4Na2O5—691.85 [17372-87-1]—Red to brownish-red pieces or powder. Use ACS reagent grade.
C20H6Br4Na2O5—691.85 [17372-87-1]—Red to brownish-red pieces or powder. Use ACS reagent grade.
Epiandrosterone
(trans-Androsterone, 5
-Androstan-3
-ol-17-one),
C19H30O2—290.44 [481-29-8]—Use a suitable grade.
-Androstan-3-ol-17-one),
C19H30O2—290.44 [481-29-8]—Use a suitable grade.
[Note—A suitable grade is available as catalog number E3375 from www.sigma-aldrich.com. ]
Add the following:
),
[
20.
[Note—A suitable grade is available as catalog number 16730 from www.caymanchem.com.
2S (USP38)
Equilenin,
C18H18O2—266.33 [517-09-9]—Colorless or white crystals or crystalline powder. Insoluble in water; soluble in chloroform and in dioxane; moderately soluble in alcohol.
C18H18O2—266.33 [517-09-9]—Colorless or white crystals or crystalline powder. Insoluble in water; soluble in chloroform and in dioxane; moderately soluble in alcohol.
Melting range, Class II 741 :
between 256 and 260.
741 :
between 256 and 260.
Specific rotation 781 :
between +85 and +88, determined in a solution in dioxane containing 75 mg of equilenin in each 10 mL.
781 :
between +85 and +88, determined in a solution in dioxane containing 75 mg of equilenin in each 10 mL.
Absorption maxima—
An alcohol solution exhibits absorption maxima at 231, 282, 325, and 340 nm.
-Ergocryptine,
C32H41N5O5—575.70 [511-09-1]—Use a suitable grade.
Eriochrome Black T–Sodium Chloride Indicator—
Mix 0.1 g of eriochrome black T and 10 g of sodium chloride, and triturate until the mixture becomes homogenous.
Eriochrome Cyanine R,
C23H15Na3O9S—536.40 [3564-18-9]—Dark, red-brown powder. Freely soluble in water; insoluble in alcohol.
C23H15Na3O9S—536.40 [3564-18-9]—Dark, red-brown powder. Freely soluble in water; insoluble in alcohol.
Solubility—
200 mg in 100 mL of water yields a solution that remains clear and free from undissolved matter for 30 minutes.
Loss on drying 731—
Dry it in vacuum over silica gel to constant weight: it loses not more than 2% of its weight.
731—
Dry it in vacuum over silica gel to constant weight: it loses not more than 2% of its weight.
Residue on ignition (Reagent test)—
0.5 g, treated with 1 mL of sulfuric acid and 2 mL of nitric acid, yields between 42.0% and 44.0% of the dry weight (theoretical yield is 42.9% of Na2SO4).
Sensitiveness—
Add 2 mL of a solution (1 in 1000) to 1 mL of aluminum sulfate solution (1 in 10,000), heat at 37 ± 3 for 5 minutes, cool, and add 1 mL of sodium acetate TS: a strong red to red-violet color is produced in not more than 5 minutes.
for 5 minutes, cool, and add 1 mL of sodium acetate TS: a strong red to red-violet color is produced in not more than 5 minutes.
Escin
[6805-41-0]—Use a suitable grade.
[6805-41-0]—Use a suitable grade.
Ethanesulfonic Acid,
C2H5SO3H—110.13 [594-45-6]—Colorless to light yellow liquid. Soluble in water.
C2H5SO3H—110.13 [594-45-6]—Colorless to light yellow liquid. Soluble in water.
Assay—
Accurately weigh about 300 mg, dissolve in 30 mL of water, add phenolphthalein TS, and titrate with 0.1 N sodium hydroxide VS. Each mL of 0.1 N sodium hydroxide is equivalent to 11.013 mg of C2H5SO3H: between 94.0% and 106.0% is found.
Refractive index 831:
between 1.432 and 1.436 at 20.
831:
between 1.432 and 1.436 at 20.
Ether, Peroxide-Free (Diethyl Ether; Ether),
(C2H5)2O—74.12—Use ACS reagent grade.
(C2H5)2O—74.12—Use ACS reagent grade.
Peroxide—
Transfer 8 mL of potassium iodide and starch TS to a 12-mL ground glass-stoppered cylinder about 15 mm in diameter. Fill completely with the substance under test, mix, and allow to stand protected from light for 5 minutes. No color develops. Alternatively, peroxide test strips may be used.
[Note—Suitable peroxide test strips can be obtained from EMD Chemicals, www.emdchemicals.com. ]
Ethidium Bromide,
C21H20N3Br—394.3 [1239-45-8]—Purple to purple-red powder. Use a suitable grade.
C21H20N3Br—394.3 [1239-45-8]—Purple to purple-red powder. Use a suitable grade.
4¢-Ethoxyacetophenone,
C10H12O2—164.20 [1676-63-7]—White to tan crystals.
C10H12O2—164.20 [1676-63-7]—White to tan crystals.
Assay—
Dissolve about 50 mg in 1 mL of ether. Inject about 1 µL of this solution into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector and a 0.25-mm × 30-m capillary column containing stationary phase G1. The carrier gas is helium. The chromatograph is programmed as follows. Initially, the column temperature is equilibrated at 180, then the temperature is increased at a rate of 10 per minute to 280, and maintained at 280 for 10 minutes. The injection port temperature is maintained at 280, and the detector is maintained at 300. The area of the 4¢-ethoxyacetophenone peak is not less than 97.5% of the total peak area.
621) equipped with a flame-ionization detector and a 0.25-mm × 30-m capillary column containing stationary phase G1. The carrier gas is helium. The chromatograph is programmed as follows. Initially, the column temperature is equilibrated at 180, then the temperature is increased at a rate of 10 per minute to 280, and maintained at 280 for 10 minutes. The injection port temperature is maintained at 280, and the detector is maintained at 300. The area of the 4¢-ethoxyacetophenone peak is not less than 97.5% of the total peak area.
Melting range 741:
between 34 and 39.
741:
between 34 and 39.
2-Ethoxyethanol
(Ethylene Glycol Monoethyl Ether),
C4H10O2—90.12 [110-80-5]—Clear, colorless liquid. Miscible with water, with alcohol, with ether, and with acetone.
C4H10O2—90.12 [110-80-5]—Clear, colorless liquid. Miscible with water, with alcohol, with ether, and with acetone.
Specific gravity 841 :
about 0.93.
841 :
about 0.93.
Boiling range (Reagent test)—
Not less than 95% distills between 133 and 135.
and 135.
Ethyl Acetate,
CH3COOC2H5—88.11 [141-78-6]—Use ACS reagent grade.
CH3COOC2H5—88.11 [141-78-6]—Use ACS reagent grade.
Ethyl Acrylate
[140-88-5]—Use a suitable grade.
[140-88-5]—Use a suitable grade.
Ethyl Alcohol
(Alcohol; Ethanol),
C2H5OH—46.07—Use Alcohol.
C2H5OH—46.07—Use Alcohol.
Ethyl Arachidate,
C22H44O2—340.6 [18281-05-5]—Use a suitable grade.
C22H44O2—340.6 [18281-05-5]—Use a suitable grade.
Ethyl Benzoate,
C9H10O2—150.17 [93-89-0]—Clear, colorless liquid. Practically insoluble in water; miscible with alcohol, with chloroform, and with ether.
C9H10O2—150.17 [93-89-0]—Clear, colorless liquid. Practically insoluble in water; miscible with alcohol, with chloroform, and with ether.
Assay—
Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621), helium being used as the carrier gas. The following conditions have been found suitable: a 3-mm × 2.4-m stainless steel column containing 20% phase G16 on support S1A; the injection port, column, and detector temperatures are maintained at 180, 195, and 250, respectively. The area of the ethyl benzoate peak is not less than 98% of the total peak area.
621), helium being used as the carrier gas. The following conditions have been found suitable: a 3-mm × 2.4-m stainless steel column containing 20% phase G16 on support S1A; the injection port, column, and detector temperatures are maintained at 180, 195, and 250, respectively. The area of the ethyl benzoate peak is not less than 98% of the total peak area.
Refractive index 831:
between 1.5048 and 1.5058 at 20.
831:
between 1.5048 and 1.5058 at 20.
Ethyl Cyanoacetate,
CNCH2COOC2H5—113.11 [105-56-6]—Colorless to pale yellow liquid. Slightly soluble in water. Miscible with alcohol and with ether. At atmospheric pressure it boils between 205 and 209, with decomposition. At a pressure of 10 mm of mercury it distills at about 90.
CNCH2COOC2H5—113.11 [105-56-6]—Colorless to pale yellow liquid. Slightly soluble in water. Miscible with alcohol and with ether. At atmospheric pressure it boils between 205 and 209, with decomposition. At a pressure of 10 mm of mercury it distills at about 90.
Specific gravity 841 :
between 1.057 and 1.062.
841 :
between 1.057 and 1.062.
Acidity—
Dissolve 2 mL in 25 mL of neutralized alcohol, add phenolphthalein TS, and titrate with 0.10 N sodium hydroxide: not more than 1.5 mL is required to produce a pink color.
Ethyl Ether
(Diethyl Ether; Ether),
(C2H5)2O—74.12 [60-29-7]—Use ACS reagent grade.
(C2H5)2O—74.12 [60-29-7]—Use ACS reagent grade.
Ethyl Ether, Anhydrous
(Diethyl Ether, Anhydrous; Ether, Absolute),
(C2H5)2O—74.12 [60-29-7]—Use ACS reagent grade.
(C2H5)2O—74.12 [60-29-7]—Use ACS reagent grade.
Ethyl Salicylate,
C9H10O3—166.17 [118-61-6]—Colorless liquid.
C9H10O3—166.17 [118-61-6]—Colorless liquid.
Assay—
Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 10-m capillary column coated with a 1-µm layer of methylsilicone; the injection port temperature is maintained at 240; the detector temperature is maintained at 300; the column temperature is maintained at 150 and programmed to rise 10 per minute to 250. The area of the ethyl salicylate peak is not less than 99% of the total peak area.
621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 10-m capillary column coated with a 1-µm layer of methylsilicone; the injection port temperature is maintained at 240; the detector temperature is maintained at 300; the column temperature is maintained at 150 and programmed to rise 10 per minute to 250. The area of the ethyl salicylate peak is not less than 99% of the total peak area.
Refractive index 831:
between 1.5216 and 1.5236 at 20.
831:
between 1.5216 and 1.5236 at 20.
2-Ethylaminopropiophenone Hydrochloride,
C6H5COCH(CH3)NHC2H5·HCl—213.70 [51553-17-4]—Use a suitable grade.
C6H5COCH(CH3)NHC2H5·HCl—213.70 [51553-17-4]—Use a suitable grade.
4-Ethylbenzaldehyde,
C2H5C6H4CHO—134.18 [4748-78-1]—Colorless to pale yellow liquid.
C2H5C6H4CHO—134.18 [4748-78-1]—Colorless to pale yellow liquid.
Assay—
Dissolve about 600 mg, accurately weighed, in a mixture of 100 mL of alcohol and 25 mL of 1 M hydroxylamine hydrochloride in a beaker. Cover the beaker with a watch glass. Heat gently until condensate begins to form on the watch glass. Allow to cool for about 30 minutes. Titrate with 0.5 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.5 N sodium hydroxide is equivalent to 67.09 mg of C2H5C6H4CHO. Not less than 98% is found.
Ethylbenzene,
C8H10—106.17 [100-41-4]—Not less than 99.5%.
C8H10—106.17 [100-41-4]—Not less than 99.5%.
Ethylene Dichloride
(1,2-Dichloroethane),
C2H4Cl2—98.96 [107-06-2]—Use ACS reagent grade 1,2-Dichloroethane.
C2H4Cl2—98.96 [107-06-2]—Use ACS reagent grade 1,2-Dichloroethane.
Ethylene Glycol,
HOCH2CH2OH—62.07 [107-21-1]—Clear, colorless, slightly viscous, hygroscopic liquid. Slightly soluble in ether; practically insoluble in benzene. Miscible with water and with alcohol.
HOCH2CH2OH—62.07 [107-21-1]—Clear, colorless, slightly viscous, hygroscopic liquid. Slightly soluble in ether; practically insoluble in benzene. Miscible with water and with alcohol.
Specific gravity 841:
about 1.11.
841:
about 1.11.
Boiling range (Reagent test):
between 194 and 200.
and 200.
Residue on ignition—
Evaporate 100 mL (110 g) in a tared evaporating dish over a flame until the vapors continue to burn after the flame is removed. Allow the vapors to burn until the specimen is consumed. Ignite at 800 ± 25 for 1 hour, cool, and weigh: the residue weighs not more than 5.5 mg (0.005%).
for 1 hour, cool, and weigh: the residue weighs not more than 5.5 mg (0.005%).
Acidity—
Add 0.2 mL of phenol red TS to 50 mL of water, and titrate with 0.1 N sodium hydroxide to a red endpoint. Add 50 mL (55 g) of ethylene glycol, and titrate with 0.1 N sodium hydroxide: not more than 1 mL is required to restore the red color (0.01% as CH3COOH).
Chloride (Reagent test)—
A 4.5-mL (5-g) portion shows not more than 0.025 mg of Cl (5 ppm).
Water, Method I 921:
not more than 0.20%.
921:
not more than 0.20%.
Ethylene Oxide in Methylene Chloride (50 mg/mL)—
Use a suitable grade.
[Note—A suitable grade is available from Sigma Aldrich Corporation, www.sigma-aldrich.com. ]
Ethylenediamine
(1,2-Diaminoethane)
C2H8N2—60.10[107-15-3]—Use a suitable grade with a content of not less than 99%.
C2H8N2—60.10[107-15-3]—Use a suitable grade with a content of not less than 99%.
N-Ethylmaleimide
(1-Ethyl-1H-pyrrole 2,5-Dione),
C6H7NO2—125.12 [128-53-0]—Use a suitable grade.
C6H7NO2—125.12 [128-53-0]—Use a suitable grade.
Melting range 741:
between 43 and 47.
741:
between 43 and 47.
2-Ethyl-2-methylsuccinic Acid,
C7H12O4—160.17—White crystals.
C7H12O4—160.17—White crystals.
Assay—
Transfer about 80 mg, accurately weighed, to a suitable beaker, add 30 mL of methanol, and dissolve by stirring. Slowly add 40 mL of deionized water. [Note—If cloudiness appears when adding the deionized water, dissolve in 50 mL of methanol only. ] When solution is complete, titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank titration, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 16.02 mg of C7H12O4. Not less than 98.5% of C7H12O4 is found.
Melting point 741:
between 101 and 103.
741:
between 101 and 103.
1-Ethylquinaldinium Iodide,
C12H14IN—299.15 [606-55-3]—Yellow-green solid. Sparingly soluble in water.
C12H14IN—299.15 [606-55-3]—Yellow-green solid. Sparingly soluble in water.
Assay—
Dissolve about 290 mg, accurately weighed, in 100 mL of water, and add 10 mL of glacial acetic acid. Titrate with 0.1 N silver nitrate VS, determining the endpoint potentiometrically, using a silver-ion selective electrode and a calomel reference electrode containing 1 M potassium nitrate. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N silver nitrate is equivalent to 29.92 mg of C12H14IN: not less than 97.0% is found.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Reagent | Margareth R. C. Marques, Ph.D.
Senior Scientific Liaison (301) 816-8106 |
(HDQ) Headquarters |