Bromophenol blue - wikipedia Bromophenol blue Bromophenol blue Names IUPAC name 4, 4 ′ - ( 1, 1 - dioxido - 3H - 2, 1 - benzoxathiole - 3, 3 - diyl ) bis ( 2, 6 - dibromophenol ) Identifiers CAS Number 115 - 39 - 9 3D model ( JSmol ) Interactive image ChEBI CHEBI : 59424 ChEMBL ChEMBL2103765 ChemSpider 7973 ECHA InfoCard 100.003. 715 PubChem CID 8272 InChI InChI = 1S / C19H10Br4O5S / c20 - 12 - 5 - 9 ( 6 - 13 ( 21 ) 17 ( 12 ) 24 ) 19 ( 10 - 7 - 14 ( 22 ) 18 ( 25 ) 15 ( 23 ) 8 - 10 ) 11 - 3 - 1 - 2 - 4 - 16 ( 11 ) 29 ( 26, 27 ) 28 - 19 / h1 - 8, 24 - 25H Key : UDSAIICHUKSCKT - UHFFFAOYSA - N InChI = 1 / C19H10Br4O5S / c20 - 12 - 5 - 9 ( 6 - 13 ( 21 ) 17 ( 12 ) 24 ) 19 ( 10 - 7 - 14 ( 22 ) 18 ( 25 ) 15 ( 23 ) 8 - 10 ) 11 - 3 - 1 - 2 - 4 - 16 ( 11 ) 29 ( 26, 27 ) 28 - 19 / h1 - 8, 24 - 25H Key : UDSAIICHUKSCKT - UHFFFAOYAE SMILES Brc1cc ( cc ( Br ) c1O ) C3 ( OS ( = O ) ( = O ) c2ccccc23 ) c4cc ( Br ) c ( O ) c ( Br ) c4 Properties Chemical formula C H Br O S Molar mass 669.96 g mol Odor odorless Density 2.2 g / mL Melting point 273 ° C ( 523 ° F ; 546 K ) Boiling point 279 ° C ( 534 ° F ; 552 K ) Except where otherwise noted, data are given for materials in their standard state ( at 25 ° C ( 77 ° F ), 100 kPa ). N verify ( what is ? ) Infobox references Bromophenol blue ( 3 ′, 3 '', 5 ′, 5 '' - tetrabromophenolsulfonphthalein, BPB, albutest ) is used as a pH indicator, a color marker, and a dye. It can be prepared by slowly adding excess bromine to a hot solution of phenolsulfonphthalein in glacial acetic acid. Contents 1 Acid -- base indicator 2 Color marker 3 Dye 4 External links 5 References Acid -- base indicator Bromophenol blue ( pH indicator ) below pH 3.0 above pH 4.6 3.0 ⇌ 4.6 As an acid -- base indicator, its useful range lies between pH 3.0 and 4.6. It changes from yellow at pH 3.0 to blue at pH 4.6 ; this reaction is reversible. Bromophenol blue is structurally related to phenolphthalein ( a popular indicator ). Color marker Bromophenol blue is also used as a color marker to monitor the process of agarose gel electrophoresis and polyacrylamide gel electrophoresis. Since bromophenol blue carries a slight negative charge at moderate pH, it will migrate in the same direction as DNA or protein in a gel ; the rate at which it migrates varies according to gel density and buffer composition, but in a typical 1 % agarose gel in a 1X TAE buffer or TBE buffer, bromophenol blue migrates at the same rate as a DNA fragment of about 300 base pairs, in 2 % agarose as 150 bp. Xylene cyanol and orange G may also be used for this purpose. Dye Bromophenol blue is also used as a dye. At neutral pH, the dye absorbs red light most strongly and transmits blue light. Solutions of the dye, therefore, are blue. At low pH, the dye absorbs ultraviolet and blue light most strongly and appears yellow in solution. In solution at pH 3.6 ( in the middle of the transition range of this pH indicator ) obtained by dissolution in water without any pH adjustment, bromophenol blue has a characteristic green red color, where the apparent color shifts depending on the concentration and / or path length through which the solution is observed. This phenomenon is called dichromatic color. Bromophenol blue is the substance with the highest known value of Kreft 's dichromaticity index. This means it has the largest change in color hue, when the thickness or concentration of observed sample increases or decreases. External links Bromophenol blue at OpenWetWare References Jump up ^ Santa Cruz Biotechnology, Inc. Bromophenol Blue ( CAS 115 - 39 - 9 ) Properties. https://www.scbt.com/scbt/product/bromophenol-blue-115-39-9 Jump up ^ Reaxys. Bromophenol blue ( 115 - 39 - 9 ) Chemical Names and Synonyms. Jump up ^ PubChem Compound. Bromphenol Blue - Compound Summary. https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=8272&loc=ec_rcs Jump up ^ PubChem Compound. Bromphenol Blue - Use and Manufacturing. https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=8272&loc=ec_rcs Jump up ^ http://www.sigmaaldrich.com/Graphics/COfAInfo/SigmaSAPQM/SPEC/B0/B0126/B0126-BULK________SIAL_____.pdf Jump up ^ `` Agarose gel electrophoresis ( basic method ) ''. Retrieved 2008 - 04 - 07. Jump up ^ Kreft S, Kreft M ( 2007 ). `` Physicochemical and physiological basis of dichromatic colour ''. Naturwissenschaften. 94 ( 11 ) : 935 -- 9. Bibcode : 2007NW... 94... 935K. doi : 10.1007 / s00114 - 007 - 0272 - 9. PMID 17534588. Jump up ^ Kreft S, Kreft M. ( 2009 ). `` Quantification of dichromatism : a characteristic of color in transparent materials ''. Journal of the Optical Society of America A. 26 ( 7 ) : 1576 -- 1581. Bibcode : 2009JOSAA... 26.1576 K. doi : 10.1364 / JOSAA. 26.001576. PMID 19568292. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Bromophenol_blue&oldid=825670207 '' Categories : PH indicators Triarylmethane dyes Phenol dyes Bromoarenes Benzoxathioles Hidden categories : Articles without KEGG source Articles without UNII source Articles with changed EBI identifier ECHA InfoCard ID from Wikidata Articles containing unverified chemical infoboxes Talk Contents About Wikipedia Deutsch Español Esperanto Français हिन्दी Italiano Nederlands 日本 語 Polski Português Русский Српски / srpski Srpskohrvatski / српскохрватски Suomi Tiếng Việt 中文 7 more Edit links This page was last edited on 14 February 2018, at 18 : 29. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what is the purpose of the bromophenol blue dye in the samples
Answer: a pH indicator; as a pH indicator