Bromothymol blue

Other Names Bromothymol blue Phenol, 4,4 -(3H-2,l-benzoxathiol-3-ylidene)i w[2-bromo-3-methyl-6-(l-methylethyl)-, S,S-dioxide Thymol, 6,6 -(3H-2,l-benzoxathiol-3-ylidene)i [2-bromo-, S,S-dioxide 3H-2,l-Benzoxathiole, phenol deriv. 3,3 -Dibromothymolsulfonphthalein 3,3 -DibromothymoIsulfophthalein Bromthymol blue Dibromothymolsulfophthalein NSC 7819 CA Index Name Phenol, 4,4 -( 1,1 -dioxido-3H-2,1 -benzoxathiol-3-ylidene)fcis[2-bromo-3-methyl-6-(l-methylethyl)-CAS Registry Number 76-59-5 Merck Index Number 1445 Chemical Structure 

Chemical/Dye Class Sulfonephthalein Molecular Formula C27H28Bf205S Molecular Weight 624.38 pH Range 6.0-7.6 

Physical Form Light pink or cream colored powder 

Solubility Sparingly soluble in water, benzene soluble in ethanol, ether insoluble in petroleum ether UV-Visible ( imax) 420 nm, 435 nm, 620 nm Melting Point 201°C 

Boiling Point (Calcd.) 614.3 55.0°C Pressure 760 Torr Synthesis Synthetic methods  

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Standardization—External standards, standard additions, and internal standards are a common feature of many quantitative analyses. Suggested experiments using these standardization methods are found in later chapters. A good project experiment for introducing external standardization, standard additions, and the importance of the sample s matrix is to explore the effect of pH on the quantitative analysis of an acid-base indicator. Using bromothymol blue as an example, external standards can be prepared in a pH 9 buffer and used to analyze samples buffered to different pHs in the range of 6-10. Results can be compared with those obtained using a standard addition. 

Titration curve for 50.00 ml of 0.100 M CH3COOH with 0.100 M NaOH showing the range of pHs and volumes of titrant over which the indicators bromothymol blue and phenolphthalein are expected to change color. 

The purity of a pharmaceutical preparation of sulfanilamide, C6H4N2O2S, can be determined by oxidizing the sulfur to SO2 and bubbling the SO2 through H2O2 to produce H2SO4. The acid is then titrated with a standard solution of NaOH to the bromothymol blue end point, where both of sulfuric acid s acidic protons have been neutralized. Calculate the purity of the preparation, given that a 0.5136-g sample required 48.13 mL of 0.1251 M NaOH. 

Ultraviolet/visible absorption spectrum for bromothymol blue. 

For crystal sulfamic acid assay, a simplified procedure of neutralization titration with sodium hydroxide solution may be used. At the end point, Bromothymol Blue (BTB) indicator changes color from yellow to yellowish green. A 1-mL solution of l/2NNaOH is equivalent to 0.0485 g of sulfamic acid. 

PHOTOMETRIC DETERMINATION OF ACIDIC IMPURITIES IN OILS AND ORGANIC LIQUIDS WITH THE USE OF THE ION PAIR OF TRINONYLOCTADECYLAMMONIUM AND BROMOTHYMOL BLUE AS THE COLORED REAGENT... 

In this work we studied the interaction of the ion pair Bromothymol Blue (BTB-trinonyloctadecylammonium (TNODA) with organic acids in toluene and its mixtures with different solvents and proposed the method for determination of carboxylic acids in solvents, oils, and other chemicals. 

Bromothymol blue or commercial universal indicator pH paper (graduated in 0.2-pH units) may be used as external indicators. 

Bromothymol blue (6.0...7.6) acid lipids, cholesterol glucuronides and gangliosides [241] aryloxybutanolamine derivatives [242] norfenfluramine derivatives [243] ethylamphetamines [244] in volatile mineral oil hydrocarbons [245] phospholipids [91]... 

Sulphonphthaleins. These indicators are usually supplied in the acid form. They are rendered water-soluble by adding sufficient sodium hydroxide to neutralise the sulphonic acid group. One gram of the indicator is triturated in a clean glass mortar with the appropriate quantity of 0.1 M sodium hydroxide solution, and then diluted with water to 1 L. The following volumes of 0.1 M sodium hydroxide are required for 1 g of the indicators bromophenol blue, 15.0 mL bromocresol green, 14.4 mL bromocresol purple, 18.6 mL chlorophenol red, 23.6 mL bromothymol blue, 16.0 mL phenol red, 28.4 mL thymol blue, 21.5 mL cresol red, 26.2 mL metacresol purple, 26.2 mL. 

Another recipe for a universal indicator is as follows 0.05 g of methyl orange, 0.15 g of methyl red, 0.3 g of bromothymol blue, and 0.35 g of phenolphthalein in 1 L of 66 per cent ethanol. The colour changes are pH up to 3, red pH 4, orange-red pH 5, orange pH 6, yellow pH 7, yellowish-green pH 8, greenish-blue pH 9, blue pH 10, violet pH 11, reddish-violet. Several universal indicators are available commercially as solutions and as test papers. 

With 0.01M solutions, the ideal pH range is still further limited to 5.5-8.5 such indicators as methyl red, bromothymol blue, or phenol red will be suitable. The titration error for methyl orange will be 1-2 per cent. 

Bromothymol blue reagent 45 Brucine 60, 67, 315, 316 Bufotenine 380 Bunitrolol 429... 

Place about 10 mL of water in a 25-mL beaker. Add a few grains of solid bromothymol blue. Stir until the bromothymol blue has dissolved. 

The indicator bromothymol blue is green in a neutral solution, yellow in an acidic solution, and blue in a basic solution. Record in Data Table 1 whether the electrolyte was acidic, neutral, or basic at each electrode. 

The sol-gel co-immobilization of a non-fluorescent blue indicator bromothymol blue (BTB) with an europium (Ill)-complex intense antenna mediated lanthanide dye represents a new scheme for the fluorescence analysis38. Luminescence spectra of europium (Ill)-complex shown in Figure 12 were found to be independent of pH changes in the range 1-10. Therefore, BTB, a non-fluorescent pH indicator with alkaline absorption maximum close to main europium emission band was added to the sol-gel mixture to shield reversibly the emission of the europium (Ill)-complex at different pH s without quenching of the antenna function. 

Figure 13 shows pH response of bromothymol blue (BTB) as coimmobilized non fluorescent pH indicator detect by fluorescence. 

The way of enzyme entrapment has been described79 proposing the application of sol-gel matrices. The optodes of urea sensor were prepared by the sol-gel method and were stored in a refrigerator. As the pH sensitive dye the bromothymol blue was used. Since it is best acting in pH range 6 to 7.6, the pH of sol-gel bulks obtained in the experiment was chosen as pH 6. Before measurements, the optodes were incubated in the temperature 36.6°C. 

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