Magnesium, Mg—24.305—Silvery metal in ribbon form.Reacts slowly with water at room temperature.Dissolves readily in dilute acids with the liberation of hydrogen.
Assay—
Transfer 1g,accurately weighed,to a 250-mLvolumetric flask,and dissolve in a mixture of 15mLof hydrochloric acid and 85mLof water.When solution is complete,dilute with water to volume,and mix.Pipet 25mLof the dilution into a 400-mLbeaker,dilute with water to 250mL,add 20mLof ammonia-ammonium chloride TSand a few mg of eriochrome black Ttrituration,and titrate with 0.1Medetate disodium VSto a blue endpoint.Each mLof 0.1Medetate disodium VSis equivalent to 2.430mg of Mg.Not less than 99%is found.
Magnesium Acetate, Mg(C2H3O2)2·4H2O—214.45—Use ACSreagent grade.
Magnesium Chloride, MgCl2·6H2O—203.30—Use ACSreagent grade.
Magnesium Nitrate, Mg(NO3)2·6H2O—256.41—Use ACSreagent grade.
Magnesium Oxide, MgO—40.30—Use ACSreagent grade.
Magnesium Oxide,Chromatographic —Use a suitable grade.
Magnesium Perchlorate,Anhydrous, Mg(ClO4)2—223.21—Use ACSreagent 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—Use ACSreagent grade.
Magnesium Sulfate,Anhydrous, MgSO4—120.37—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 275to 300until the weight is practically constant.Transfer the product while still warm to tight containers,as the anhydrous salt is very hygroscopic.
Malachite Green G —See Brilliant Green.
Maleic Acid, C4H4O4—116.07—White,odorless,crystalline powder.Soluble in 1.5parts of water,in 2parts of alcohol,and in 12parts of ether.
Assay—
Dissolve about 2g,accurately weighed,in 100mLof water and titrate with 1Nsodium hydroxide VS,using phenolphthalein TSas the indicator.Each mLof 1Nsodium hydroxide is equivalent to 58.04mg 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 2hours:it loses not more than 1.5%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Manganese Dioxide— See Manganese Dioxide,Activated.
Manganese Dioxide,Activated (Manganese(IV)Oxide,Activated), MnO2—86.94—Use a suitable grade.
Add the following:
Melamine
(2,4,6-Triamino-1,3,5-triazine),
C3H6N6—126.1[108-78-1]—Use a suitable grade.USP28
2-Mercaptoethanol (b-Mercaptoethanol), C2H6OS—78.13[60-24-2]—Use a suitable grade.
Mercuric Acetate, Hg(C2H3O2)2—318.68—Use ACSreagent grade.
Mercuric Bromide, HgBr2—360.40—Use ACSreagent grade.
Mercuric Chloride, HgCl2—271.50—Use ACSreagent grade.
Mercuric Iodide,Red, HgI2—454.40—Use ACSreagent grade.
Mercuric Nitrate, Hg(NO3)2·xH2O—342.62—Use ACSreagent grade.This reagent is available as either the mono-or dihydrate.
Mercurous Nitrate Dihydrate (Mercury(I)Nitrate Dihydrate), Hg2(NO3)2·2H2O—561.22—Use ACSreagent grade.
Mercuric Oxide,Yellow, HgO—216.59—Use ACSreagent grade.
Mercuric Sulfate, HgSO4—296.65—Use ACSreagent grade.
Mercuric Thiocyanate, Hg(SCN)2—316.76—White,crystalline powder.Very slightly soluble in water;soluble in solutions of sodium chloride;slightly soluble in alcohol and in ether.
Mercury, Hg—At.Wt.200.59—Use ACSreagent grade.
Mesityl Oxide, C6H10O—98.14—Colorless liquid.
Assay—
Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography á621ñ)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 50and programmed to rise 10per minute to 200.The area of the C6H10Opeak is not less than 98%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 50and programmed to rise 10per minute to 200.The area of the C6H10Opeak is not less than 98%of the total peak area.
Refractive index á831ñ:
between 1.443and 1.447at 20.
.
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.
Solubility—
Asolution of 1g in 200mLof water is colorless.
Residue on ignition(Reagent test)—
Ignite 1g with 0.5mLof sulfuric acid:the residue weighs not more than 1mg (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—Use ACSreagent grade.
Methacrylic Acid —Use a suitable grade.
Methacrylic Carboxylic Acid Cation-exchange Resin —See Cation-exchange Resin,Methacrylic Carboxylic Acid.
Methanesulfonic Acid, CH4O3S—96.11—Use a suitable grade.
Methanol (Methyl Alcohol), CH3OH—32.04—Use ACSreagent grade.
Add the following:
Methanol,Aldehyde-Free,
CH3OH—32.04—Dissolve 25g of iodine in 1Lof methanol and pour the solution,with constant stirring,into 400mLof 1Nsodium hydroxide.Add 150mLof water,and allow to stand for 16hours.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.USP28
Methanol,Anhydrous —Use Methanol.
Methanol,Spectrophotometric —Use ACSreagent grade Methanol Suitable for Use in UV Spectrophotometry.
Methenamine— Use Methenamine(USPmonograph).
Methoxyethanol (Ethylene Glycol Monomethyl Ether;2-Methoxyethanol), CH3OCH2CH2OH—76.09—Use ACSreagent grade.
2-Methoxyethanol (Ethylene Glycol Monomethyl Ether;Methoxyethanol), CH3OCH2CH2OH—76.09—See Methoxyethanol.
5-Methoxy-2-methyl-3-indoleacetic Acid, C12H13NO3—219.24—Off-white powder.
Assay—
Transfer about 110mg,accurately weighed,to a 100-mLbeaker.Add 30mLof methanol and dissolve by stirring.Add 40mLof water,and mix.Titrate with 0.1Nsodium hydroxide VS,determining the endpoint potentiometrically.Perform a blank determination and make any necessary correction.Each mLof 0.1Nsodium hydroxide is equivalent to 21.92mg of C12H13NO3.Not less than 98%is found.
Melting range á741ñ:
between 161and 168,but the range between beginning and end of melting does not exceed 3.
and 168,but the range between beginning and end of melting does not exceed 3.
Methyl Acetate, C3H6O2—74.08—Colorless liquid,having a characteristic odor.Soluble in water.Miscible with alcohol and with ether.Specific gravity:about 0.933.
Refractive index á831ñ:
between 1.3615and 1.3625at 20.
.
Boiling range(Reagent test)—
Not less than 95%distils between 57and 58.
and 58.
Methyl 4-Aminobenzoate, C8H9NO2—151.16—Off-white powder.
Assay—
Dissolve about 38mg,accurately weighed,in 50mLof glacial acetic acid.Titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 15.12mg of C8H9NO2.Not less than 99.0%is found.
Methyl Arachidate, C21H42O2—326.56—Off-white flakes.
Assay—
Inject an appropriate specimen into a gas chromatograph (see Chromatography á621ñ)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%G2phase on support S1A;the injection port temperature is maintained at 300;the detector temperature is maintained at 300;the column temperature is maintained at 230and programmed to rise 3per minute to 280.The area of the C2H42O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 230and programmed to rise 3per minute to 280.The area of the C2H42O2peak is not less than 99%of the total peak area.
Methyl Behenate, C23H46O2—354.61—White powder.
Assay—
Inject an appropriate specimen into a gas chromatograph (see Chromatography á621ñ)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%G3phase 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 2minutes,and then programmed to rise 3per minute to attain a final temperature of 270,which is held for 10minutes.The area of the C23H46O2peak is not less than 98%of the total peak area.
;the detector temperature is maintained at 300;the initial temperature of the oven is 220,which is held for 2minutes,and then programmed to rise 3per minute to attain a final temperature of 270,which is held for 10minutes.The area of the C23H46O2peak is not less than 98%of the total peak area.
Methyl Benzenesulfonate, C7H8O3S—172.20[80-18-2]—Use a suitable grade.
Methyl Caprate, C11H22O2—186.29—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 150and programmed to rise 10per minute to 280.The area of the C11H22O2peak is not less than 98.5%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 150and programmed to rise 10per minute to 280.The area of the C11H22O2peak is not less than 98.5%of the total peak area.
Methyl Caprylate, C9H18O2—158.24—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 130and programmed to rise 10per minute to 280.The area of the C9H18O2peak is not less than 98.5%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 130and programmed to rise 10per minute to 280.The area of the C9H18O2peak is not less than 98.5%of the total peak area.
Methyl Carbamate C2H5NO2—75.07—White crystals.Freely soluble in water.
Methyl Chloroform (Methylchloroform;1,1,1-Trichloroethane), CH3CCl3—133.40—Use ACSreagent grade.
5,5¢-Methylenedisalicylic Acid (3,3¢-Methylene-bis[6-hydroxybenzoic Acid]), C15H12O6—288.25—Use a suitable grade.
Methyl Erucate, C23H44O2—352.59—Colorless liquid.
Methyl Ethyl Ketone, CH3COC2H5—72.11—Use ACSreagent grade 2-butanone.
Methyl Green, C27H35N3BrCl·ZnCl2—653.24[7114-03-6]—Use a suitable grade.
Methyl Heptadecanoate, C18H36O2—284.48—White,crystalline flakes.
Assay—
Inject an appropriate specimen into a gas chromatograph (see Chromatography á621ñ)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 180and programmed to rise 4per minute to 220.The area of the C18H36O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 220;the column temperature is maintained at 180and programmed to rise 4per minute to 220.The area of the C18H36O2peak is not less than 99%of the total peak area.
Methyl Iodide, CH3I—141.94—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.
Assay—
Add 1mLto a 100-mLvolumetric flask tared with 10mLof alcohol.Weigh again,add alcohol to volume,and mix.Pipet 20mLinto a glass-stoppered flask,and add 50.0mLof 0.1Nsilver nitrate VSand 2mLof nitric acid.Insert the stopper immediately,shake frequently during 2hours,and allow to stand in the dark overnight.Shake again during 2hours,then add 50mLof water and 3mLof ferric ammonium sulfate,and titrate the excess silver nitrate with 0.1Nammonium thiocyanate VS.Each mLof 0.1Nsilver nitrate is equivalent to 14.19mg of CH3I:not less than 98.5%is found.
Boiling range(Reagent test)—
Distill 50mLinto a chilled,partly closed receiver:not less than 48mLdistils between 41.5and 43.
and 43.
Density:
between 2.270and 2.285.
Residue on evaporation—
Evaporate 4mL(10g)on a steam bath,and dry the residue at 105for 1hour:the residue weighs not more than 1mg (0.01%).
for 1hour:the residue weighs not more than 1mg (0.01%).
Acidity—
Shake 3mLwith 5mLof water for 30seconds,and immediately draw off the lower layer:the aqueous layer is neutral to litmus and when 1mLof silver nitrate TSis added,it shows not more than a slight opalescence.
Methyl Isobutyl Ketone —See 4-Methyl-2-pentanone.
Methyl Laurate, C13H26O2—214.34—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 180and programmed to rise 10per minute to 280.The area of the C13H26O2peak is not less than 99.45%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 180and programmed to rise 10per minute to 280.The area of the C13H26O2peak is not less than 99.45%of the total peak area.
Methyl Lignocerate, C25H50O2—382.66—White crystals.
Methyl Linoleate, C19H34O2—294.47—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 200and programmed to rise 10per minute to 300.The area of the C19H34O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 200and programmed to rise 10per minute to 300.The area of the C19H34O2peak is not less than 99%of the total peak area.
Methyl Linolenate, C19H32O2—292.46—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 180and programmed to rise 10per minute to 280.The area of the C19H32O3peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 180and programmed to rise 10per minute to 280.The area of the C19H32O3peak is not less than 99%of the total peak area.
Refractive index á831ñ:
between 1.469and 1.473at 20.
.
Methyl Methacrylate —Use a suitable grade.
Methyl Myristate, C15H30O2—242.40—Colorless liquid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 200and programmed to rise 10per minute to 300.The area of the C15H30O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 200and programmed to rise 10per minute to 300.The area of the C15H30O2peak is not less than 99%of the total peak area.
Refractive index á831ñ:
between 1.434and 1.438at 20.
.
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.
Melting range á741ñ:
between 59and 63,but the range between beginning and end of melting does not exceed 2.
and 63,but the range between beginning and end of melting does not exceed 2.
Methyl Oleate, C19H36O2—296.49—Colorless liquid.
Assay—
Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography á621ñ)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 230and programmed to rise 10per minute to 280.The area of the C19H36O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 230and programmed to rise 10per minute to 280.The area of the C19H36O2peak is not less than 99%of the total peak area.
Refractive index á831ñ:
1.452at 20.
.
Methyl Palmitate, C17H34O2—270.45—White solid.
Assay—
Inject an appropriate volume into a gas chromatograph (see Chromatography á621ñ)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 200and programmed to rise 10per minute to 300.The area of the C17H34O2peak is not less than 96.5%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained at 200and programmed to rise 10per minute to 300.The area of the C17H34O2peak is not less than 96.5%of the total peak area.
Methyl Stearate, C19H38O2—298.50—Off-white,crystalline solid.
Assay—
Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography á621ñ)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 200and programmed to rise 10per minute to 300.The area of the C19H38O2peak is not less than 99%of the total peak area.
;the detector temperature is maintained at 300;the column temperature is maintained 200and programmed to rise 10per minute to 300.The area of the C19H38O2peak is not less than 99%of the total peak area.
Methyl Sulfoxide (Dimethyl Sulfoxide), (CH3)2SO—78.13—Use ACSreagent grade.
Methylamine,40Percent in Water, CH5N—31.06—Colorless liquid.
Assay—
Using a syringe,transfer about 0.5mLof a well-shaken specimen to 100mLof 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 0.5Nhydrochloric acid VS,determining the endpoint potentiometrically,using a silver-silver chloride pHelectrode and a calomel reference electrode.Perform a blank determination,and make any necessary correction.Each mLof 0.5Nhydrochloric acid is equivalent to 15.53mg of CH5N:between 39.0%and 41.0%is found.
Refractive index á831ñ:
between 1.3680and 1.3710,at 20.
.
p-Methylaminophenol Sulfate, (p-CH3NHC6H4OH)2·H2SO4—344.38—Use ACSreagent grade.
4-Methylbenzophenone, C14H12O—196.25[134-84-9]—Use a suitable grade.
Add the following:
Methylbenzothiazolone Hydrazone Hydrochloride,
C8H10CIN3S·H2O—233.7—An almost white or yellowish,crystalline powder.
Melting point á741ñ:
about 270.
.
Suitability for determination of adehydes—
To 2mLof aldehyde-free methanol add 60µLof a 1g per Lsolution of propionaldehyde in aldehyde-free methanol and 5mLof a 4g per Lsolution of methylbenzothiazolone hydrazone hydrochloride.Mix,and allow to stand for 30minutes.Prepare a blank,omitting the propionaldehyde solution.Add 25.0mLof a 2g per Lsolution of ferric chloride to the test solution and to the blank,dilute with acetone to 100.0mL,and mix.The absorbance of the test solution,measured at 660nm using the blank as compensation liquid,is not less than 0.62.USP28
USP28
(S)-(-)-a-Methylbenzyl Isocyanate C9H9NO—147.18[14649-03-7]—Use a suitable grade.
Methylene Blue, C16H18ClN3S·3H2O—373.90—Dark green crystals or a crystalline powder,having a bronze-like luster.One g dissolves in about 25mLof water and in about 65mLof alcohol.Soluble in chloroform.
Absorptivity ratio—
The ratio of its absorptivity (see Spectrophotometry and Light-scattering á851ñ)at 635nm to that at 665nm,measured in a dilute solution of the dye in diluted alcohol,is between 0.56and 0.62.
Residue on ignition(Reagent test)—
Ignite 1g with 0.5mLof sulfuric acid:the residue weighs not more than 10mg (1%).
Loss on drying á731ñ—
Dry it at 105for 18hours:it loses not more than 15.0%of its weight.
for 18hours:it loses not more than 15.0%of its weight.
Methylene Chloride (Dichloromethane), CH2Cl2—84.93—Use ACSreagent grade Dichloromethane.
3-O-Methylestrone, C19H24O2—284.39—Use a suitable grade.
[NOTE—Commercially available as catalog number 1883-5from Research Plus,Inc.,P.O.Box 324,Bayonne,NJ07002,fax number 908-754-2901,Web site:www.researchplus.com.]
2-Methyl-5-nitroimidazole, C4H4N3O2—127.10[88052-22-2]—Use a suitable grade.
4-Methyl-2-pentanone (Methyl Isobutyl Ketone), (CH3)2CHCH2COCH3—100.16—Use ACSreagent grade.
2-Methyl-2-propyl-1,3-propanediol, C7H16O2—132.20—White crystals,melting at about 58
.
N-Methylpyrrolidine (1-Methylpyrrolidine), C4H8NCH3—85.15[120-94-5]—Use ACSreagent grade.
Methyl Yellow (p-Dimethylaminoazobenzene), C14H15N3—225.3[60-11-7]—Use a suitable grade.
Mineral Acid —Use Hydrochloric Acid or Sulfuric Acid.
Molybdic Acid (85Percent Molybdic Acid) —Use ACSreagent grade.
Monobasic Potassium Phosphate —See Potassium Phosphate,Monobasic.
Monobasic Sodium Phosphate —See Sodium Phosphate,Monobasic.
Monochloroacetic Acid,(Chloroacetic Acid,Chloroethanoic Acid) CH2ClCOOH—94.50—Use ACSreagent grade.
Monoethanolamine,(2-Aminoethanol) C2H7NO—61.08—Use ACSreagent grade.
Morpholine (Tetrahydro-1,4-oxazine), C4H9NO—87.12—Use ACSreagent grade.