Magnesium,
Mg—24.305 [7439-95-4]—Silvery metal in ribbon form. Reacts slowly with water at room temperature. Dissolves readily in dilute acids with the liberation of hydrogen.
Mg—24.305 [7439-95-4]—Silvery metal in ribbon form. Reacts slowly with water at room temperature. Dissolves readily in dilute acids with the liberation of hydrogen.
Assay—
Transfer 1 g, accurately weighed, to a 250-mL volumetric flask, and dissolve in a mixture of 15 mL of hydrochloric acid and 85 mL of water. When solution is complete, dilute with water to volume, and mix. Pipet 25 mL of the dilution into a 400-mL beaker, dilute with water to 250 mL, add 20 mL of ammonia–ammonium chloride TS and a few mg of eriochrome black T trituration, and titrate with 0.1 M edetate disodium VS to a blue endpoint. Each mL of 0.1 M edetate disodium VS is equivalent to 2.430 mg of Mg. Not less than 99% is found.
Magnesium Acetate,
Mg(C2H3O2)2·4H2O—214.45 [142-72-3]—Use ACS reagent grade.
Mg(C2H3O2)2·4H2O—214.45 [142-72-3]—Use ACS reagent grade.
Change to read:
Magnesium Chloride,
MgCl2·6H2O—203.30 [
USP38
Change to read:
Magnesium Nitrate,
Mg(NO3)2·6H2O—256.41 [USP38
Magnesium Oxide,
MgO—40.30 [1309-48-4]—Use ACS reagent grade.
MgO—40.30 [1309-48-4]—Use ACS reagent grade.
Magnesium Oxide, Chromatographic
—Use a suitable grade.
Magnesium Perchlorate, Anhydrous,
Mg(ClO4)2—223.21 [10034-81-8]—Use ACS reagent grade.
Mg(ClO4)2—223.21 [10034-81-8]—Use ACS reagent grade.
Magnesium Silicate, Activated
—Use a suitable grade.
Magnesium Silicate, Chromatographic
—Extremely white, hard, powdered (60- to 100-mesh) magnesia–silica gel. Suitable for use as an adsorbant in column chromatography.
Magnesium Sulfate,
MgSO4·7H2O—246.48 [10034-99-8]—Use ACS reagent grade.
MgSO4·7H2O—246.48 [10034-99-8]—Use ACS reagent grade.
Magnesium Sulfate, Anhydrous,
MgSO4—120.37 [7487-88-9]—Anhydrous Magnesium Sulfate may be prepared as follows. Place a suitable quantity of magnesium sulfate (see above), preferably powdered, in a shallow vessel, and expose to a temperature of about 80
for several hours with occasional stirring. Then heat at 275 to 300 until the weight is practically constant. Transfer the product while still warm to tight containers, as the anhydrous salt is very hygroscopic.
MgSO4—120.37 [7487-88-9]—Anhydrous Magnesium Sulfate may be prepared as follows. Place a suitable quantity of magnesium sulfate (see above), preferably powdered, in a shallow vessel, and expose to a temperature of about 80 for several hours with occasional stirring. Then heat at 275 to 300 until the weight is practically constant. Transfer the product while still warm to tight containers, as the anhydrous salt is very hygroscopic.
Maleic Acid,
C4H4O4—116.07 [110-16-7]—White, crystalline powder. Soluble in 1.5 parts of water, in 2 parts of alcohol, and in 12 parts of ether.
C4H4O4—116.07 [110-16-7]—White, crystalline powder. Soluble in 1.5 parts of water, in 2 parts of alcohol, and in 12 parts of ether.
Assay—
Dissolve about 2 g, accurately weighed, in 100 mL of water and titrate with 1 N sodium hydroxide VS, using phenolphthalein TS as the indicator. Each mL of 1 N sodium hydroxide is equivalent to 58.04 mg of C4H4O4: not less than 99% of C4H4O4, calculated on the dried basis, is found.
Loss on drying—
Dry it in vacuum over phosphorus pentoxide for 2 hours: it loses not more than 1.5% of its weight.
Residue on ignition 
281
:
not more than 0.1%.
281:
not more than 0.1%.
Maltotriose,
C18H32O16—504.44[1109-28-0]—Use a suitable grade with a content of not less than 95%.
C18H32O16—504.44[1109-28-0]—Use a suitable grade with a content of not less than 95%.
Add the following:
[
2S (USP38)
Manganese Dioxide, Activated
(Manganese (IV) Oxide, Activated),
MnO2—86.94 [1313-13-9]—Use a suitable grade.
MnO2—86.94 [1313-13-9]—Use a suitable grade.
Medium-Chain Triglycerides
(Caprylic/Capric Triglycerides, Glyceryl Tricaprylate/Caprate)
[438544-49-1]—Use a suitable grade containing NLT 95% of saturated fatty acids with 8 and 10 carbon atoms. [Note—A suitable grade is available as Captex 300 low C6 from www.abiteccorp.com. ]
[438544-49-1]—Use a suitable grade containing NLT 95% of saturated fatty acids with 8 and 10 carbon atoms. [Note—A suitable grade is available as Captex 300 low C6 from www.abiteccorp.com. ]
Melamine
(2,4,6-Triamino-1,3,5-triazine),
C3H6N6—126.1 [108-78-1]—Use a suitable grade.
C3H6N6—126.1 [108-78-1]—Use a suitable grade.
2-Mercaptoethanol
(
-Mercaptoethanol),
C2H6OS—78.13 [60-24-2]—Use a suitable grade.
-Mercaptoethanol),
C2H6OS—78.13 [60-24-2]—Use a suitable grade.
Mercuric Acetate,
Hg(C2H3O2)2—318.68 [1600-27-7]—Use ACS reagent grade.
Hg(C2H3O2)2—318.68 [1600-27-7]—Use ACS reagent grade.
Mercuric Bromide,
HgBr2—360.40 [7789-47-1]—Use ACS reagent grade.
HgBr2—360.40 [7789-47-1]—Use ACS reagent grade.
Mercuric Chloride,
HgCl2—271.50 [7487-94-7]—Use ACS reagent grade.
HgCl2—271.50 [7487-94-7]—Use ACS reagent grade.
Mercuric Iodide, Red,
HgI2—454.40 [7774-29-0]—Use ACS reagent grade.
HgI2—454.40 [7774-29-0]—Use ACS reagent grade.
Mercuric Nitrate,
Hg(NO3)2·xH2O—342.62 [10045-94-0]—Use ACS reagent grade. This reagent is available as either the mono- or dihydrate.
Hg(NO3)2·xH2O—342.62 [10045-94-0]—Use ACS reagent grade. This reagent is available as either the mono- or dihydrate.
Mercuric Oxide, Yellow,
HgO—216.59 [21908-53-2]—Use ACS reagent grade.
HgO—216.59 [21908-53-2]—Use ACS reagent grade.
Mercuric Sulfate,
HgSO4—296.65 [7783-35-9]—Use ACS reagent grade.
HgSO4—296.65 [7783-35-9]—Use ACS reagent grade.
Mercuric Thiocyanate,
Hg(SCN)2—316.76 [592-85-8]—White, crystalline powder. Very slightly soluble in water; soluble in solutions of sodium chloride; slightly soluble in alcohol and in ether.
Hg(SCN)2—316.76 [592-85-8]—White, crystalline powder. Very slightly soluble in water; soluble in solutions of sodium chloride; slightly soluble in alcohol and in ether.
Mercurous Nitrate Dihydrate (Mercury (I) Nitrate Dihydrate),
Hg2(NO3)2·2H2O—561.22—Use ACS reagent grade.
Hg2(NO3)2·2H2O—561.22—Use ACS reagent grade.
Mercury,
Hg—At. Wt. 200.59 [7439-97-6]—Use ACS reagent grade.
Hg—At. Wt. 200.59 [7439-97-6]—Use ACS reagent grade.
Mesityl Oxide,
C6H10O—98.14 [141-79-7]—Colorless liquid.
C6H10O—98.14 [141-79-7]—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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 150; the detector temperature is maintained at 300; the column temperature is maintained at 50 and programmed to rise 10 per minute to 200. The area of the C6H10O peak is not less than 98% 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 150; the detector temperature is maintained at 300; the column temperature is maintained at 50 and programmed to rise 10 per minute to 200. The area of the C6H10O peak is not less than 98% of the total peak area.
Refractive index 831:
between 1.443 and 1.447 at 20.
831:
between 1.443 and 1.447 at 20.
Metanil Yellow (Acid Yellow 36; 3-(4-Anilinophenylazo)benzenesulfonic Acid Sodium Salt),
C18H14N3NaO3S—375.38[587-98-4]—Use a suitable grade with a dye content of NLT 70%.
C18H14N3NaO3S—375.38[587-98-4]—Use a suitable grade with a dye content of NLT 70%.
Metaphenylenediamine Hydrochloride
(Metaphenylenediamine Dihydrochloride),
C6H4(NH2)2·2HCl—181.06—White or slightly reddish-white, crystalline powder. Easily soluble in water. On exposure to light it acquires a reddish color. Store it protected from light.
C6H4(NH2)2·2HCl—181.06—White or slightly reddish-white, crystalline powder. Easily soluble in water. On exposure to light it acquires a reddish color. Store it protected from light.
Solubility—
A solution of 1 g in 200 mL of water is colorless.
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%).
[Note—Metaphenylenediamine hydrochloride solution can be decolorized by treatment with a small quantity of activated charcoal. ]
Metaphosphoric Acid
(Vitreous Sodium Acid Metaphosphate),
HPO3—79.98 [37267-86-0]—Use ACS reagent grade.
HPO3—79.98 [37267-86-0]—Use ACS reagent grade.
Methacrylic Acid
[79-41-4]—Use a suitable grade.
[79-41-4]—Use a suitable grade.
Methanesulfonic Acid,
CH4O3S—96.11 [75-75-2]—Use a suitable grade.
CH4O3S—96.11 [75-75-2]—Use a suitable grade.
Methanol
(Methyl Alcohol),
CH3OH—32.04 [67-56-1]—Use ACS reagent grade.
CH3OH—32.04 [67-56-1]—Use ACS reagent grade.
Methanol, Aldehyde-Free,
CH3OH—32.04—Dissolve 25 g of iodine in 1 L of methanol and pour the solution, with constant stirring, into 400 mL of 1 N sodium hydroxide. Add 150 mL of water, and allow to stand for 16 hours. Filter, and boil under a reflux condenser until the odor of iodoform disappears. Distill the solution by fractional distillation. It contains not more than 0.001% of aldehydes and ketones.
CH3OH—32.04—Dissolve 25 g of iodine in 1 L of methanol and pour the solution, with constant stirring, into 400 mL of 1 N sodium hydroxide. Add 150 mL of water, and allow to stand for 16 hours. Filter, and boil under a reflux condenser until the odor of iodoform disappears. Distill the solution by fractional distillation. It contains not more than 0.001% of aldehydes and ketones.
Methanol, Spectrophotometric
—Use ACS reagent grade Methanol Suitable for Use in UV Spectrophotometry.
Methenamine
(Hexamethylenetetramine; Urotropine; Uritone; Hexamine),
C6H12N4—140.19 [100-97-0]—Use ACS reagent grade Hexamethylenetetramine.
C6H12N4—140.19 [100-97-0]—Use ACS reagent grade Hexamethylenetetramine.
7-Methoxycoumarin
(Herniarin; Methyl Umbelliferyl Ether),
C10H8O3—176.17[531-59-9]—Use a suitable grade with a content of not less than 98%.
C10H8O3—176.17[531-59-9]—Use a suitable grade with a content of not less than 98%.
Methoxyethanol
(Ethylene Glycol Monomethyl Ether; 2-Methoxyethanol),
CH3OCH2CH2OH—76.09 [109-86-4]—Use ACS reagent grade.
CH3OCH2CH2OH—76.09 [109-86-4]—Use ACS reagent grade.
2-Methoxyethanol
(Ethylene Glycol Monomethyl Ether; Methoxyethanol),
CH3OCH2CH2OH—76.09 [109-86-4]—See Methoxyethanol.
CH3OCH2CH2OH—76.09 [109-86-4]—See Methoxyethanol.
5-Methoxy-1H-benzimidazole-2-thiol
(5-Methoxy-2-benzimidazolethiol),
C8H8N2OS—180.23[37052-78-1]—Use a suitable grade with a content of NLT 99.0%.
C8H8N2OS—180.23[37052-78-1]—Use a suitable grade with a content of NLT 99.0%.
5-Methoxy-2-methyl-3-indoleacetic Acid,
C12H13NO3—219.24 [2882-15-7]—Off-white powder.
C12H13NO3—219.24 [2882-15-7]—Off-white powder.
Assay—
Transfer about 110 mg, accurately weighed, to a 100-mL beaker. Add 30 mL of methanol and dissolve by stirring. Add 40 mL of water, and mix. Titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank determination and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 21.92 mg of C12H13NO3. Not less than 98% is found.
Melting range 741 :
between 161 and 168, but the range between beginning and end of melting does not exceed 3.
741 :
between 161 and 168, but the range between beginning and end of melting does not exceed 3.
Methoxyphenylacetic Acid
(
-Methoxyphenylacetic Acid),
C9H10O3—166.2 [7021-09-2]—Use a suitable grade.
-Methoxyphenylacetic Acid),
C9H10O3—166.2 [7021-09-2]—Use a suitable grade.
Methyl Acetate,
C3H6O2—74.08 [74-20-9]—Colorless liquid. Soluble in water. Miscible with alcohol and with ether.
C3H6O2—74.08 [74-20-9]—Colorless liquid. Soluble in water. Miscible with alcohol and with ether.
Specific gravity 841:
about 0.933.
841:
about 0.933.
Refractive index 831:
between 1.3615 and 1.3625 at 20.
831:
between 1.3615 and 1.3625 at 20.
Boiling range (Reagent test)—
Not less than 95% distills between 57 and 58.
and 58.
Methyl 4-Aminobenzoate,
C8H9NO2—151.16 [619-45-4]—Off-white powder.
C8H9NO2—151.16 [619-45-4]—Off-white powder.
Assay—
Dissolve about 38 mg, accurately weighed, in 50 mL of glacial acetic acid. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 15.12 mg of C8H9NO2. Not less than 99.0% is found.
Melting range 741 :
between 108 and 110.
741 :
between 108 and 110.
Methyl Arachidate
(Eicosanoic acid, methyl ester),
C21H42O2—326.56 [1120-28-1]—Off-white flakes.
C21H42O2—326.56 [1120-28-1]—Off-white flakes.
Assay—
Inject an appropriate specimen into a gas chromatograph (see Chromatography 621) equipped with a thermal-conductivity detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2.0-mm × 1.8-m glass column packed with 5% G2 phase on support S1A; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 230 and programmed to rise 3 per minute to 280. The area of the C2H42O2 peak is not less than 99% of the total peak area.
621) equipped with a thermal-conductivity detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2.0-mm × 1.8-m glass column packed with 5% G2 phase on support S1A; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 230 and programmed to rise 3 per minute to 280. The area of the C2H42O2 peak is not less than 99% of the total peak area.
Melting range 741:
between 46 and 51.
741:
between 46 and 51.
Methyl Behenate,
C23H46O2—354.61 [929-77-1]—White powder.
C23H46O2—354.61 [929-77-1]—White powder.
Assay—
Inject an appropriate specimen into a gas chromatograph (see Chromatography 621) equipped with a thermal conductivity detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2.0-mm × 1.8-m glass column packed with 5% G3 phase on support S1A; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the initial temperature of the oven is 220, which is held for 2 minutes, and then programmed to rise 3 per minute to attain a final temperature of 270, which is held for 10 minutes. The area of the C23H46O2 peak is not less than 98% of the total peak area.
621) equipped with a thermal conductivity detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2.0-mm × 1.8-m glass column packed with 5% G3 phase on support S1A; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the initial temperature of the oven is 220, which is held for 2 minutes, and then programmed to rise 3 per minute to attain a final temperature of 270, which is held for 10 minutes. The area of the C23H46O2 peak is not less than 98% of the total peak area.
Melting range 741:
between 54 and 56.
741:
between 54 and 56.
Methyl Benzenesulfonate,
C7H8O3S—172.20 [80-18-2]—Use a suitable grade.
C7H8O3S—172.20 [80-18-2]—Use a suitable grade.
Methyl Caprate,
C11H22O2—186.29 [110-42-9]—Colorless liquid.
C11H22O2—186.29 [110-42-9]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 250; the detector temperature is maintained at 300; the column temperature is maintained at 150 and programmed to rise 10 per minute to 280. The area of the C11H22O2 peak is not less than 98.5% 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 250; the detector temperature is maintained at 300; the column temperature is maintained at 150 and programmed to rise 10 per minute to 280. The area of the C11H22O2 peak is not less than 98.5% of the total peak area.
Methyl Caprylate,
C9H18O2—158.24 [111-11-5]—Colorless liquid.
C9H18O2—158.24 [111-11-5]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 230; the detector temperature is maintained at 300; the column temperature is maintained at 130 and programmed to rise 10 per minute to 280. The area of the C9H18O2 peak is not less than 98.5% 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 230; the detector temperature is maintained at 300; the column temperature is maintained at 130 and programmed to rise 10 per minute to 280. The area of the C9H18O2 peak is not less than 98.5% of the total peak area.
Methyl Carbamate,
C2H5NO2—75.07 [598-55-0]—White crystals. Freely soluble in water.
C2H5NO2—75.07 [598-55-0]—White crystals. Freely soluble in water.
Melting range 741:
between 54 and 56.
741:
between 54 and 56.
Methyl Chloroform
(Methylchloroform; 1,1,1-Trichloroethane),
CH3CCl3—133.40 [71-55-6]—Use ACS reagent grade.
CH3CCl3—133.40 [71-55-6]—Use ACS reagent grade.
Methyl Erucate,
C23H44O2—352.59 [1120-34-9]—Colorless liquid.
C23H44O2—352.59 [1120-34-9]—Colorless liquid.
Methyl Ethyl Ketone,
CH3COC2H5—72.11 [78-93-3]—Use ACS reagent grade 2-butanone.
CH3COC2H5—72.11 [78-93-3]—Use ACS reagent grade 2-butanone.
Methyl Green
(Methyl Green Zinc Chloride Double Salt; Ethyl Green Zinc Chloride Double Salt; C.I. 42590),
C27H35Cl2N3·ZnCl2—608.78[7114-03-6]—Use a suitable grade for microscopy.
C27H35Cl2N3·ZnCl2—608.78[7114-03-6]—Use a suitable grade for microscopy.
Methyl Heptadecanoate,
C18H36O2—284.48 [1731-92-6]—White, crystalline flakes.
C18H36O2—284.48 [1731-92-6]—White, crystalline flakes.
Assay—
Inject an appropriate specimen into a 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 × 30-m capillary column coated with a 1-µm layer of phase G8; the injection port temperature is maintained at 220; the detector temperature is maintained at 220; the column temperature is maintained at 180 and programmed to rise 4 per minute to 220. The area of the C18H36O2 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 × 30-m capillary column coated with a 1-µm layer of phase G8; the injection port temperature is maintained at 220; the detector temperature is maintained at 220; the column temperature is maintained at 180 and programmed to rise 4 per minute to 220. The area of the C18H36O2 peak is not less than 99% of the total peak area.
Melting range 741:
between 31 and 32.
741:
between 31 and 32.
Methyl Hexanoate
(Caproic Acid Methyl Ester; Methyl Caproate),
C7H14O2—130.18[106-70-7]—Use a suitable grade with a content of NLT 99%.
C7H14O2—130.18[106-70-7]—Use a suitable grade with a content of NLT 99%.
[Note—A suitable grade is available as catalog 259942 from www.sigma-aldrich.com. ]
Methyl Iodide,
(Iodomethane),
CH3I—141.94 [74-88-4]—Colorless, heavy, transparent liquid. Slightly soluble in water. Miscible with alcohol, with ether, and with solvent hexane. Turns brown on exposure to light as a result of liberation of iodine.
CH3I—141.94 [74-88-4]—Colorless, heavy, transparent liquid. Slightly soluble in water. Miscible with alcohol, with ether, and with solvent hexane. Turns brown on exposure to light as a result of liberation of iodine.
Use a suitable grade with a content of not less than 99%.
Methyl Laurate,
C13H26O2—214.34 [110-82-0]—Colorless liquid.
C13H26O2—214.34 [110-82-0]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 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; the column temperature is maintained at 180 and programmed to rise 10 per minute to 280. The area of the C13H26O2 peak is not less than 99.45% 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 × 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; the column temperature is maintained at 180 and programmed to rise 10 per minute to 280. The area of the C13H26O2 peak is not less than 99.45% of the total peak area.
Methyl Lignocerate,
C25H50O2—382.66 [2442-49-1]—White crystals.
C25H50O2—382.66 [2442-49-1]—White crystals.
Methyl Linoleate,
C19H34O2—294.47 [112-63-0]—Colorless liquid.
C19H34O2—294.47 [112-63-0]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C19H34O2 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C19H34O2 peak is not less than 99% of the total peak area.
Methyl Linolenate,
C19H32O2—292.46 [301-00-8]—Colorless liquid.
C19H32O2—292.46 [301-00-8]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase 14% cyanopropylphenyl-86% dimethylpolysiloxane; the injection port temperature is maintained at 280; the detector temperature is maintained at 300; the column temperature is maintained at 180 and programmed to rise 10 per minute to 280. The area of the C19H32O2 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 × 30-m capillary column coated with a 1-µm layer of phase 14% cyanopropylphenyl-86% dimethylpolysiloxane; the injection port temperature is maintained at 280; the detector temperature is maintained at 300; the column temperature is maintained at 180 and programmed to rise 10 per minute to 280. The area of the C19H32O2 peak is not less than 99% of the total peak area.
Refractive index 831:
between 1.469 and 1.473 at 20.
831:
between 1.469 and 1.473 at 20.
Methyl Methacrylate
[80-62-6]—Use a suitable grade.
[80-62-6]—Use a suitable grade.
Methyl Myristate,
C15H30O2—242.40 [124-10-7]—Colorless liquid.
C15H30O2—242.40 [124-10-7]—Colorless liquid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C15H30O2 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C15H30O2 peak is not less than 99% of the total peak area.
Refractive index 831:
between 1.434 and 1.438 at 20.
831:
between 1.434 and 1.438 at 20.
Methyl Oleate,
C19H36O2—296.49 [112-62-9]—Colorless liquid.
C19H36O2—296.49 [112-62-9]—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 capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 230 and programmed to rise 10 per minute to 280. The area of the C19H36O2 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 capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 230 and programmed to rise 10 per minute to 280. The area of the C19H36O2 peak is not less than 99% of the total peak area.
Refractive index 831:
1.452 at 20.
831:
1.452 at 20.
Methyl Palmitate,
C17H34O2—270.45 [112-39-0]—White solid.
C17H34O2—270.45 [112-39-0]—White solid.
Assay—
Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C17H34O2 peak is not less than 96.5% 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C17H34O2 peak is not less than 96.5% of the total peak area.
Methyl Palmitoleate
(Methyl cis-9-Hexadecenoate; Palmitoleic Acid Methyl Ester),
C17H32O2—268.43[1120-25-8]—Use a suitable grade with a content of NLT 99%. [Note—A suitable grade is available as catalog number P9667 or 76176 from www.sigma-aldrich.com. ]
C17H32O2—268.43[1120-25-8]—Use a suitable grade with a content of NLT 99%. [Note—A suitable grade is available as catalog number P9667 or 76176 from www.sigma-aldrich.com. ]
Methyl Red
(2-[4-Dimethylaminophenylazo]benzoic Acid; C. I. Acid Red 2)
C15H15N3O2, free acid— 269.30[493-52-7] C15H14N3O2Na, sodium salt—291.28[845-10-3]—Use ACS reagent grade. The free acid is recommended for nonaqueous titrations, particularly when an aprotic solvent is used. The sodium salt is recommended for titrations in aqueous media and also for nonaqueous titrations where the medium is an amphiprotic solvent. The hydrochloride salt is recommended for titrations in aqueous media and amphiprotic solvents.
C15H15N3O2, free acid— 269.30[493-52-7] C15H14N3O2Na, sodium salt—291.28[845-10-3]—Use ACS reagent grade. The free acid is recommended for nonaqueous titrations, particularly when an aprotic solvent is used. The sodium salt is recommended for titrations in aqueous media and also for nonaqueous titrations where the medium is an amphiprotic solvent. The hydrochloride salt is recommended for titrations in aqueous media and amphiprotic solvents.
Methyl Stearate,
C19H38O2—298.50 [112-61-8]—Off-white, crystalline solid.
C19H38O2—298.50 [112-61-8]—Off-white, crystalline solid.
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 capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C19H38O2 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 capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 300; the detector temperature is maintained at 300; the column temperature is maintained at 200 and programmed to rise 10 per minute to 300. The area of the C19H38O2 peak is not less than 99% of the total peak area.
Melting range 741:
between 40 and 42.
741:
between 40 and 42.
Methyl p-Toluenesulfonate
(Methyl Toluene-4-sulfonate),
C8H10SO3—186.23[80-48-8]—Use a suitable grade with a content of NLT 98%.
C8H10SO3—186.23[80-48-8]—Use a suitable grade with a content of NLT 98%.
Methyl Yellow
(p-Dimethylaminoazobenzene),
C14H15N3—225.3 [60-11-7]—Use a suitable grade.
C14H15N3—225.3 [60-11-7]—Use a suitable grade.
Methylamine, 40 Percent in Water,
CH5N—31.06 [74-89-5]—Colorless liquid.
CH5N—31.06 [74-89-5]—Colorless liquid.
Assay—
Using a syringe, transfer about 0.5 mL of a well-shaken specimen to 100 mL of water at a point below the surface of the water. Determine the weight of the specimen by weighing the syringe before and after the transfer. Mix, and titrate with 0.5 N hydrochloric acid VS, determining the endpoint potentiometrically, using a silver-silver chloride pH electrode and a calomel reference electrode. Perform a blank determination, and make any necessary correction. Each mL of 0.5 N hydrochloric acid is equivalent to 15.53 mg of CH5N: between 39.0% and 41.0% is found.
Refractive index 831 :
between 1.3680 and 1.3710, at 20.
831 :
between 1.3680 and 1.3710, at 20.
Add the following:
[
USP38
p-Methylaminophenol Sulfate,
(p-CH3NHC6H4OH)2·H2SO4—344.38 [55-55-0]—Use ACS reagent grade.
(p-CH3NHC6H4OH)2·H2SO4—344.38 [55-55-0]—Use ACS reagent grade.
4-Methylbenzophenone,
C14H12O—196.25 [134-84-9]—Use a suitable grade.
C14H12O—196.25 [134-84-9]—Use a suitable grade.
Melting range 741:
between 56.5 and 57.
741:
between 56.5 and 57.
Methylbenzothiazolone Hydrazone Hydrochloride,
C8H10ClN3S·H2O—233.7 [38894-11-0] (monohydrate form)
—215.70 (anhydrous form);[149022-15-1] (hydrate form)—An almost white or yellowish, crystalline powder.
C8H10ClN3S·H2O—233.7 [38894-11-0] (monohydrate form)
—215.70 (anhydrous form);[149022-15-1] (hydrate form)—An almost white or yellowish, crystalline powder.
Suitability for determination of aldehydes—
To 2 mL of aldehyde-free methanol add 60 µL of a 1 g per L solution of propionaldehyde in aldehyde-free methanol and 5 mL of a 4 g per L solution of methylbenzothiazolone hydrazone hydrochloride. Mix, and allow to stand for 30 minutes. Prepare a blank, omitting the propionaldehyde solution. Add 25.0 mL of a 2 g per L solution of ferric chloride to the test solution and to the blank, dilute with acetone to 100.0 mL, and mix. The absorbance of the test solution, measured at 660 nm using the blank as compensation liquid, is not less than 0.62.
Use a suitable grade with a content of not less than 97%.
(R)-(+)-alpha-Methylbenzyl Isocyanate
((R)-(+)-1-Phenylethyl Isocyanate),
C9H9NO—147.17[33375-06-3]—Use a suitable grade with a content of NLT 99.0%.
C9H9NO—147.17[33375-06-3]—Use a suitable grade with a content of NLT 99.0%.
(S)-(
)--Methylbenzyl Isocyanate
C9H9NO—147.18 [14649-03-7]—Use a suitable grade.
)--Methylbenzyl Isocyanate
C9H9NO—147.18 [14649-03-7]—Use a suitable grade.
Methylene Blue,
C16H18ClN3S·3H2O—373.90 [7220-79-3]—Dark green crystals or a crystalline powder, having a bronzelike luster. One g dissolves in about 25 mL of water and in about 65 mL of alcohol. Soluble in chloroform. Use a suitable grade with a dye content of not less than 85%.
C16H18ClN3S·3H2O—373.90 [7220-79-3]—Dark green crystals or a crystalline powder, having a bronzelike luster. One g dissolves in about 25 mL of water and in about 65 mL of alcohol. Soluble in chloroform. Use a suitable grade with a dye content of not less than 85%.
Methylene Chloride
(Dichloromethane),
CH2Cl2—84.93 [75-09-2]—Use ACS reagent grade Dichloromethane.
CH2Cl2—84.93 [75-09-2]—Use ACS reagent grade Dichloromethane.
5,5¢-Methylenedisalicylic Acid
(3,3¢-Methylene-bis[6-hydroxybenzoic Acid]),
C15H12O6—288.25 [122-25-8]—Use a suitable grade.
C15H12O6—288.25 [122-25-8]—Use a suitable grade.
3-O-Methylestrone,
C19H24O2—284.39—Use a suitable grade.
C19H24O2—284.39—Use a suitable grade.
[Note—Commercially available as catalog number 1883-5 from Research Plus, Inc., P.O. Box 324, Bayonne, NJ 07002, fax number 908-754-2901, Web site: www.researchplus.com. ]
2-Methyl-5-nitroimidazole,
C4H4N3O2—127.10 [88052-22-2]—Use a suitable grade.
C4H4N3O2—127.10 [88052-22-2]—Use a suitable grade.
[Note—Available as Catalog No. 13,625-5 from Sigma-Aldrich, www.sigma-aldrich.com. ]
N-Methyl-N-nitroso-p-toluenesulfonamide
(p-Tolylsulfonylmethylnitrosamide),
C8H10N2O3S—214.24—Light yellow crystals or powder. Insoluble in water; soluble in benzene, in carbon tetrachloride, and in chloroform.
C8H10N2O3S—214.24—Light yellow crystals or powder. Insoluble in water; soluble in benzene, in carbon tetrachloride, and in chloroform.
Melting range 741:
between 59 and 63, but the range between beginning and end of melting does not exceed 2.
741:
between 59 and 63, but the range between beginning and end of melting does not exceed 2.
4-Methylpentan-2-ol,
C6H14O—102.2—Use a suitable grade.
C6H14O—102.2—Use a suitable grade.
2-Methylpentane
(2-Methyl-pentane; 1,1-Dimethylbutane; Isohexane),
C6H14—86.18 [107-83-5]—Use a suitable grade with a content of not less than 99.0%.
C6H14—86.18 [107-83-5]—Use a suitable grade with a content of not less than 99.0%.
4-Methyl-2-pentanone
(Methyl Isobutyl Ketone),
(CH3)2CHCH2COCH3—100.16 [108-10-1]—Use ACS reagent grade.
(CH3)2CHCH2COCH3—100.16 [108-10-1]—Use ACS reagent grade.
2-Methyl-2-propyl-1,3-propanediol,
C7H16O2—132.20 [78-26-2]—White crystals, melting at about 58.
C7H16O2—132.20 [78-26-2]—White crystals, melting at about 58.
N-Methylpyrrolidine
(1-Methylpyrrolidine),
C4H8NCH3—85.15 [120-94-5]—Use a suitable grade.
C4H8NCH3—85.15 [120-94-5]—Use a suitable grade.
Mineral Acid
—Use Hydrochloric Acid or Sulfuric Acid.
5,800, 23,700, and 100,000 Molecular Weight (MW) Pullulan Standards
(a commercial Pullulan Standard set contains standards having several molecular weights: 5,800; 12,000; 24,000; 48,000; 100,000; 186,000; 380,000; and 750,000)
[9057-02-7]—Use a suitable grade. Each individual Pullulan Standard with a different molecular weight, such as 5,800, 24,000, or 100,000, is equivalently used.
[9057-02-7]—Use a suitable grade. Each individual Pullulan Standard with a different molecular weight, such as 5,800, 24,000, or 100,000, is equivalently used.
[Note—The standard set is available from Polymer Laboratories (www.polymerlabs.com), Sigma-Aldrich (www.sigma-aldrich.com), and Waters (www.waters.com). ]
Add the following:
[
1S (USP38)
Molybdic Acid
(85 Percent Molybdic Acid)
[7782-91-4]—Use ACS reagent grade.
[7782-91-4]—Use ACS reagent grade.
Monochloroacetic Acid (Chloroacetic Acid, Chloroethanoic Acid),
CH2ClCOOH—94.50 [79-11-8]—Use ACS reagent grade.
CH2ClCOOH—94.50 [79-11-8]—Use ACS reagent grade.
Monoethanolamine, (2-Aminoethanol)
C2H7NO—61.08—Use ACS reagent grade.
C2H7NO—61.08—Use ACS reagent grade.
Morin
(Morin Hydrate; 2¢,3,4¢,5,7-Pentahydroxyflavone Monohydrate),
C15H10O7·H2O—320.25[480-16-0]—Use a suitable grade.
C15H10O7·H2O—320.25[480-16-0]—Use a suitable grade.
Morpholine
(Tetrahydro-1,4-oxazine),
C4H9NO—87.12 [110-91-8]—Use ACS reagent grade.
C4H9NO—87.12 [110-91-8]—Use ACS reagent grade.
Add the following:
[
USP38
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 |