USP 35Chemical Tests / 〈197〉 Spectrophotometric Identification Tests 133
Tartrate—Dissolve a few mg of a tartrate salt in 2 drops graphic chamber with the bottom edge touching the Devel-of sodium metaperiodate solution (1 in 20). Add a drop of oping Solvent . When the solvent front has rin about 101N sulfuric acid, and after 5 minutes add a few drops of cm, remove the sheet from the chamber, and expo the sulfurous acid followed by a few drops of fuchsin–sulfurous sheet to ammonia vapor. Examine the chromatogram under acid TS: a reddish-pink color is produced within 15 minutes.long-wavelength UV light. Record the positions of the major yellow fluorescent spots: the R F value of the principal spot Thiocyanate—With ferric chloride TS, solutions of thiocy-obtained from the Test Solution and from the Mixed Test anates yield a red color that is not destroyed by moderately Solution corresponds to that obtained from the Standard concentrated mineral acids.
Solution .
Thiosulfate—With hydrochloric acid, solutions of thiosul-fates yield a white precipitate that soon turns yellow, and sulfur dioxide, which blackens filter paper moistened with METHOD II
mercurous nitrate TS. The addition of ferric chloride TS to solutions of thiosulfates produces a dark violet color that Resolution Solution—Unless otherwi directed in the quickly disappears.
individual monograph, prepare a solution in methanol con-Zinc—In the prence of sodium acetate, solutions of taining 0.5 mg each of USP Chlortetracycline Hydrochloride zinc salts yield a white precipitate with hydrogen sulfide.RS, USP Doxycycline Hyclate RS, USP Oxytetracycline RS,This precipitate is insoluble in acetic acid, but is dissolved by and USP Tetracycline Hydrochloride RS per mL.
3N hydrochloric acid. Ammonium sulfide TS produces a Developing Solvent—Prepare a mixture of 0.5 M oxalic similar precipitate in neutral and in alkaline solutions. With acid, previously adjusted with ammonium hydroxide to a potassium ferrocyanide TS, zinc salts in solution yield a pH of 2.0, acetonitrile, and methanol (80:20:20).
white precipitate that is insoluble in 3N hydrochloric acid.
Chromatographic Plate—U a suitable thin-layer chro-matographic plate (e Thin-layer Chromatography under Chromatography 〈621〉) coated with a 0.25-mm layer of octylsilanized chromatographic silica gel mixture. Activate the plate by heating it at 130° for 20 minutes, allow to cool, and u while still warm.
Procedure—Separately apply 1 µL each of the Standard 〈193〉 IDENTIFICATION—
Solution , the Test Solution , and the Resolution Solution to the Chromatographic Plate . Allow the spots to dry, and develop TETRACYCLINES
the chromatogram in the Developing Solvent until the sol-vent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber,The following chromatographic procedures are provided mark the solvent front, and allow to air-dry. Expo the to confirm the identity of Pharmacopeial drug substances plate to ammonia vapors for 5 minutes, and promptly lo-that are of the tetracycline type, such as doxycycline, oxy-cate the spots on the plate by viewing under long-wave-tetracycline, and tetracycline, and to confirm the identity of length UV light: the chromatogram of the Resolution Solution such compounds in their respective Pharmacopeial dosage shows clearly parated spots, and the principal spot ob-forms. Two procedures are provided, one bad on paper tained from the Test Solution corresponds in R F value, inten-chromatography (Method I ) and the other on thin-layer sity, and appearance to that obtained from the Standard chromatography (Method II ). Method I is to be ud unless Solution .
英语在现翻译otherwi directed in the individual monograph.
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Standard Solution—Unless otherwi directed in the in-dividual monograph, dissolve the USP Refer
ence Standard for the drug substance being identified in the same solvent and at the same concentration as for the Test Solution .Test Solution—Prepare as directed in the individual monograph.
〈197〉 SPECTROPHOTOMETRIC
IDENTIFICATION TESTS
METHOD I
pH 3.5 Buffer—Dissolve 13.4 g of anhydrous citric acid Spectrophotometric tests contribute meaningfully toward and 16.3 g of dibasic sodium phosphate in 1000 mL of the identification of many compendial chemical substances.water, and mix.
The test procedures that follow are applicable to substances Developing Solvent—On the day of u, mix 10
that absorb IR and/or UV radiation (e Spectrophotometry volumes of chloroform, 20 volumes of nitromethane, and 3and Light-Scattering 〈851〉).
volumes of pyridine.感叹句练习
盛传
The IR absorption spectrum of a substance, compared Mixed Test Solution—Mix equal volumes of the Stan-with that obtained concomitantly for the corresponding USP dard Solution and the Test Solution .
Reference Standard, provides perhaps the most conclusive evidence of the identity of the substance that can be real-Chromatographic Sheet—Draw a spotting line 2.5 cm ized from any single test. The UV absorption spectrum, on from one edge of a 20-cm × 20-cm sheet of filter paper the other hand, does not exhibit a high degree of specific-(Whatman No. 1, or equivalent). Impregnate the sheet with ity. Conformance with both IR absorption and UV absorp-pH 3.5 Buffer by passing it through a trough filled with pH tion test specifications, as called for in a large proportion of 3.5 Buffer , and remove the excess solvent by firmly pressing compendial monographs, leaves little doubt, if any, regard-the sheet between nonfluorescent blotting papers.
ing the identity of the specimen under examination.
托福听力的弦外之音Procedure—To a suitable chromatographic chamber,prepared for ascending chromatography (e Chromatogra-phy 〈621〉) add Developing Solvent to a depth of 0.6 cm.
INFRARED ABSORPTION
Apply at 1.5-cm intervals 2 µL each of the Standard Solution ,the Test Solution , and the Mixed Test Solution to the spotting Seven methods are indicated for the preparation of previ-line of the Chromatographic Sheet . Allow the sheet to dry ously dried test specimens and Reference Standards for anal-take a break
partially, and while still damp place it in the chromato-
134〈197〉 Spectrophotometric Identification Tests / Chemical Tests
USP 35
ysis. The reference 〈197K 〉 in a monograph signifies that the and minima at the same wavelengths and absorptivities substance under examination is mixed intimately with po-and/or absorbance ratios are within specified limits.
tassium bromide. The reference 〈197M 〉 in a monograph sig-nifies that the substance under examination is finely ground and disperd in mineral oil. The reference 〈197F 〉 in a mon-ograph signifies that the substance under examination is suspended neat between suitable (for example, sodium
chloride or potassium bromide) plates. The reference 〈197S 〉signifies that a solution of designated concentration is pre-〈201〉 THIN-LAYER pared in the solvent specified in the individual monograph,and the solution is examined in 0.1-mm cells unless a differ-CHROMATOGRAPHIC ent cell path length is specified in the individual mono-graph. The reference 〈197A 〉 signifies that the substance IDENTIFICATION TEST
under examination is intimately in contact with an internal reflection element for attenuated total reflectance (ATR)analysis. The reference 〈197E 〉 signifies that the substance under examination is presd as a thin sample against a suitable plate for IR microscopic analysis. The reference GENERAL PROCEDURE
〈197D 〉 in a monograph signifies that the substance under examination is mixed intimately with an IR-transparent ma-The following procedure is applicable as an aid in verify-terial and transferred to a sample container for diffu reflec-ing the identities of many compendial drug substances as tion (DR) analysis. The ATR 〈197A 〉 and the 〈197E 〉 tech-such and in their respective dosage forms.
niques can be ud as alternative methods for 〈197K 〉,Prepare a test solution as directed in the individual mono-〈197M 〉, 〈197F 〉, and 〈197S 〉 where testing is performed
graph. On a line parallel to and about 2 cm from the edge qualitatively and the Reference Standard spectra are similarly of a suitable thin-layer chromatographic plate, coated with a obtained.declarations
0.25-mm layer of chromatographic silica gel mixture (e Record the spectra of the test specimen and the corre-Chromatography 〈621〉) apply 10 µL of this solution and 10sponding USP Reference Standard over the range from µL of a Standard solution prepared from the USP Reference about 2.6 µm to 15 µm (3800 cm –1 to 650 cm –1) unless Standard for the drug substance being identified, in the
otherwi specified in the individual monograph. The IR ab-same solvent and at the same concentration as the test solu-sorption spectrum of the preparation of the test specimen,tion, unless otherwi directed in the individual monograph.previously dried under conditions specified for the corre-Allow the spots to dry, and develop the chromatogram in a sponding Reference Standard unless otherwi specified, or solvent system consisting of a mixture of chloroform, meth-unless the Reference Standard is to be ud without drying,anol, and water (180:15:1), unless otherwi directed in the exhibits maxima only at the same wavelengths as that of a individual monograph, until the solvent front has moved similar preparation of the corresponding USP Reference about three-fourths of the length of the plate. Remove the Standard.
plate from the developing chamber, mark the solvent front,Differences that may be obrved in the spectra so ob-and allow the solvent to evaporate. Unless otherwi di-tained sometimes are attributed to the prence of poly-rected in the individual monograph, locate the spots on the morphs, which are not always acceptable (e Procedure plate by examination under short-wavelength UV light. The under Spectrophotometry and Light-Scattering 〈851〉). Unless R F value of the principal spot obtained from the test solution otherwi directed in the individual monograph, therefore,corresponds to that obtained from the Standard solution.
continue as follows. If a difference appears in the IR spectra of the analyte and the standard, dissolve equal portions of the test specimen and the Reference Standard in equal
PROCEDURE FOR BACITRACIN, NEOMYCIN,
钱英文volumes of a suitable solvent, evaporate the solution to dry-AND POLYMYXIN B
anosaness in similar containers under identical conditions, and re-peat the test on the residues.
The following thin-layer chromatographic procedure is ap-plicable as an aid in verifying the identities of bacitracin,neomycin, and polymyxin B active ingredients and in dos-ULTRAVIOLET ABSORPTION
age forms when prent singly and in two- and three-com-ponent mixtures. The reference 〈201BNP 〉 in a monograph The reference 〈197U 〉 in a monograph signifies that a test signifies that this procedure is intended.
solution and a Standard solution are examined spectropho-Prepare a Test Solution as follows, unless otherwi di-tometrically, in 1-cm cells, over the spectral range from 200rected in the 400 nm unless otherwi specified in the individual monograph.
Test Solution —
prefer的用法Dissolve a portion of the substance under examination in FOR DRUG SUBSTANCES —Dissolve a portion of Bacitracin,the designated Medium to obtain a test solution having the Bacitracin Zinc, Neomycin Sulfate, or Polymyxin B Sulfate in concentration specified in the monograph for Solution. Simi-0.1 N hydrochloric acid to obtain a solution containing larly prepare a Standard solution containing the correspond-about 500 USP Bacitracin Units per mL, 3.5 mg of neomy-ing USP Reference Standard.
cin (ba) per mL, or 10,000 USP Polymyxin B Units per mL.Record and compare the spectra concomitantly obtained FOR SOLUTIONS —Where the Solution contains neomycin for the test solu
tion and the Standard solution. Calculate and polymyxin B, dilute a portion of it with 0.1 N hydro-absorptivities and/or absorbance ratios where the criteria chloric acid to obtain a solution containing the equivalent of are included in an individual monograph. Unless otherwi about 3.5 mg of neomycin (ba) per mL. Where the Solu-specified, absorbances indicated for the calculations are tion contains polymyxin B but not neomycin, dilute a por-tho measured at the maximum absorbance at about the tion of it with 0.1 N hydrochloric acid to obtain a solution wavelength specified in the individual monograph. Where containing about 10,000 USP Polymyxin B Units per mL.the absorbance is to be measured at about the specified FOR CREAMS , LOTIONS , AND OINTMENTS —Where the Cream,wavelength other than that of maximum absorbance, the Lotion, or Ointment contains Bacitracin or Bacitracin Zinc,abbreviations (min) and (sh) are ud to indicate a mini-transfer a portion of it equivalent to about 500 USP Bacitra-mum and shoulder, respectively, in an absorption spectrum.cin Units, to a 15-mL centrifuge tube. Where the Cream,The requirements are met if the UV absorption spectra of Lotion, or Ointment contains neomycin, but not Bacitracin
the test solution and the Standard solution exhibit maxima
