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usp中缓冲溶液和标准溶液的详细配制方法BUFFERSOLUTIONSThesuc__ssfulcompletionof__nyPhar__copeialtestsandassaysrequiresadjustmenttoor__intenan__ofaspecifiedpHbytheadditionofbuffersolutions.InpHmeasurementsstandardbuffersolutionsarerequiredforreferen__purposes.Forconvenien__thepreparationofthesesolutionsisinsomeinstan__sdescribedinthesectionsinwhichtheiruseisspecified;i.e.fiveseparatephosphatebuffersaredescribedunderAntibiotics--MicrobialAssays81andseveralmis__llaneoussingle-purposesolutionsaredescribedintheindividualmonographs.Asolutionissaidtobebufferedifitresistschangesintheactivityofanionontheadditionofsubstan__sthatareexpectedtochangetheactivityofthation.Buffersaresubstan__sorcombinationsofsubstan__sthatimpartthisresistan__toasolution.Bufferedsolutionsaresystemsinwhichtheionisinequilibriumwithsubstan__scapableofremovingorreleasingtheion.Buffercapacityreferstotheamountof__terialthat__ybeaddedtoasolutionwithoutcausingasignificantchangeinionactivity.Itisdefinedastheratioofacidorbaseaddedingram-equivalentsperlitertothechangeinpHinpHunits.Thecapacityofabufferedsolutionisadjustedtotheconditionsofuseusuallybyadjustmentofthecon__ntrationsofbuffersubstan__s.Buffersareusedtoestablishand__intainanionactivitywithinnarrowlimits.Themostcommonsystemsareusedtoestablishhydrogen-ionactivityforthecalibrationofpHmetersinthepreparationofdosageformsthatapproachisotonicityin____yticalpro__duresandto__intainstabilityofvariousdosageforms.Buffersusedinphysiologicalsystemsarecarefullychosensoasnottointerferewithphar__cologicalactivityofthemedicamentornor__lfunctionoftheorgani__.Itisessentialthatbuffersusedinchemical____ysisbecompatiblewiththesubstan__determinedandthereagentsused.STANDARDBUFFERSOLUTIONS--StandardsolutionsofdefinitepHarereadily__ailableinbuffersolutionspreparedfromtheappropriatereagents.Inadditionbuffersolutionsbuffertabletsandbuffersolids__ybeobtainedfromcommercialsour__sinconvenientprepackagedform.Suchpreparationsare__ailablefortheentireworkingrangeinphar____utical____ysisbutarenotrecommendedforpHmeterstandardizationseepH
791.TherequiredreagentsaredescribedinthesectionReagents.Previouslydrythecrystallinereagentsex__pttheboricacidat110degreesto120degreesfor1hour.NOTE--Wherewaterisspecifiedforsolutionordilutionoftestsubstan__sinpHdeterminationsusecarbondioxide-freewater.StorethepreparedsolutionsinchemicallyresistanttightcontainerssuchasTypeIglassbottles.Usethesolutionswithin3months.StandardbuffersolutionsforvariousrangesbetweenpH
1.2and
10.0__ybepreparedbyappropriatecombinationsof
0.2Msolutionsdescribedhereinusedintheproportionsshownintheaccompanyingtable.Thevolumesshowninthetablearefor200mLofbuffersolution.
1.HydrochloricAcid
0.2MandSodiumHydroxide
0.2M--PrepareandstandardizeasdirectedunderVolumetricSolutions.
2.PotassiumBiphthalate
0.2M--Dissolve
40.85gofpotassiumbiphthalate[KHC
[6]H
[4]COO
[2]]inwateranddilutewithwaterto1000mL.
3.PotassiumPhosphateMonobasic
0.2M--Dissolve
27.22gofmonobasicpotassiumphosphateKH
[2]PO
[4]inwateranddilutewithwaterto1000mL.
4.BoricAcidandPotassiumChloride
0.2M--Dissolve
12.37gofboricacidH
[3]BO
[3]and
14.91gofpotassiumchlorideKClinwateranddilutewithwaterto1000mL.
5.PotassiumChloride
0.2M--Dissolve
14.91gofpotassiumchlorideKClinwateranddilutewithwaterto1000mL.
6.A__ticAcid2N--PrepareandstandardizeasdirectedunderVolumetricSolutions.CompositionofStandardBufferSolutionsSeeGraphicG-1097------------------------------------------------------------------------HydrochloricAcidBufferPla__50mLofthepotassiumchloridesolutionina200-mLvolumetricflaskaddthespecifiedvolumeofthehydrochloricacidsolutionthenaddwatertovolume.pH
1.
21.
31.
41.
51.
61.
71.
81.
92.
02.
12.2HClmL
85.
067.
253.
241.
432.
426.
020.
416.
213.
010.
27.8AcidPhthalateBufferPla__50mLofthepotassiumbiphthalatesolutionina200-mLvolumetricflaskaddthespecifiedvolumeofthehydrochloricacidsolutionthenaddwatertovolume.pH
2.
22.
42.
62.
83.
03.
23.
43.
63.
84.0HClmL
49.
542.
235.
428.
922.
315.
710.
46.
32.
90.1NeutralizedPhthalateBufferPla__50mLofthepotassiumbiphthalatesolutionina200-mLvolumetricflaskaddthespecifiedvolumeofthesodiumhydroxidesolutionthenaddwatertovolume.pH
4.
24.
44.
64.
85.
05.
25.
45.
65.8NaOHmL
3.
06.
611.
116.
522.
628.
834.
138.
842.3PhosphateBufferPla__50mLofthemonobasicpotassiumphosphatesolutionina200-mLvolumetricflaskaddthespecifiedvolumeofthesodiumhydroxidesolutionthenaddwatertovolume.pH
5.
86.
06.
26.
46.
66.
87.
07.
27.
47.
67.
88.0NaOHmL
3.
65.
68.
111.
616.
422.
429.
134.
739.
142.
444.
546.1AlkalineBorateBufferPla__50mLoftheboricacidandpotassiumchloridesolutionina200-mLvolumetricflaskaddthespecifiedvolumeofthesodiumhydroxidesolutionthenaddwatertovolume.pH
8.
08.
28.
48.
68.
89.
09.
29.
49.
69.
810.0NaOHmL
3.
96.
08.
611.
815.
820.
826.
432.
136.
940.
643.7A__tateBufferPla__thespecifiedamountofsodiuma__tateNaC
[2]H
[3]O
[2].3H
[2]Oina1000-mLvolumetricflaskaddthespecifiedvolumeofthea__ticacidsolutionthenaddwatertovolumeandmix.pH
4.
14.
34.
54.
74.
95.
15.
25.
35.
45.5pHmeasured
4.
104.
294.
514.
704.
905.
115.
185.
305.
405.48NaC
[2]H
[3]O
[2].
1.
501.
992.
993.
594.
345.
085.
235.
615.
765.983H
[2]OgCH
[3]COOHmL
19.
517.
714.
011.
89.
16.
35.
84.
43.
83.0。