Chlorophenol red

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. 

The pH change can be monitored using a colorimetric pH indicator dye such as chlorophenol red,22 phenol red or bromothymol blue41. 

Xavier M.P., Vallejo B., Marazuela M.D., Moreno-Bondi M.C., Baldini F., Falai A., Fiber optic monitoring of carbamate pesticides using porous glass with covalently bound chlorophenol red, Biosens. Bioelectron., 2000 14 895-905. 

Spectrophotometry (or colorimetry) has been used to measure chlorine dioxide in water using indicators that change colors when oxidized by chlorine dioxide. Spectrophotometric analyzers determine the concentration of chlorine dioxide by measuring the optical absorbance of the indicator in the sample solution. The absorbance is proportional to the concentration of the chlorine dioxide in water. Indicators used for this technique include jV,jV-diethyl-p-phenylenediamine, chlorophenol red, and methylene blue (APHA 1998 Fletcher and Hemming 1985 Quentel et al. 1994 Sweetin et al. 1996). For example, chlorophenol red selectively reacts with chlorine dioxide at pH 7 with a detection limit of 0.12 mg/L. The interferences from chlorine may be reduced by the addition of oxalic acid, sodium cyclamate, or thioacetamide (Sweetin et al. 1996). 

Sweetin DL, Sullivan E, Gordon G. 1996. The use of chlorophenol red for the selective determination of chlorine dioxide in drinking water. Talanta 43 103-108. 

Cresol red Crystal Violet Malachite Green Methanil Yellow Thymol Blue Orange IV -2,4-Dinitrophenol -Erythrosin, Na2 salt -Dimethyl Yellow Cl 11020 Bromophenol Blue Congo Red Cl 22120 Methyl Orange Bromocresol Green Alizarin Red S Cl 42750 Methyl Red Cl 13020 -Bromocresol Purple Chlorophenol Red p-Nitrophenol Alizarin Bromothymol Blue Brillant Yellow Phenol Red Neutral Red Cl 50040 -m-NItrophenol -Cresol Red Metacresol Purple Phenolphthalein -Thymolphthalein -P-Naphthyl Violet Alizarin Yellow R 2,4,6-T rinitrotoluene... 

Chlorophenol Red [4430-20-0] M 423.3, Xmax573nm. Crystd from glacial acetic acid. 

To determine the level of fusion between effector and target cells, 25 pi of 2% (v/v) Tween-20 was added to each well, mixed by pipetting, frozen, and thawed twice to facilitate cell lysis. Then 25 pi of lysate was transferred to a 96-well half-area plate and 25 pi of substrate solution-3-gal (8 mM chlorophenol red-/3-D-galactopiranoside, 60 mM Na2HP04 H20, 40 mM NaH2P04 H20, 10 mM KC1, 1 mM MgS04 H20, 50 mM... 

When silicotungstic acid is titrated with a base using methyl orange or chlorophenol red as the indicator, an end point is obtained when four equivalents have been added. The end point with chlorophenol is sharper because this indicator does not form a precipitate with the acid.4 When the acid is titrated using phenolphthalein as the indicator, the end point is not permanent. However, when the titration is carried out in a hot solution, an end point is reached when twenty-four equivalents of base have been added. The end products are sodium tungstate and silicic acid. 

Chlorine dioxide is determined from its absorbance as the coloured product (Xmax = 490 nm) of its reaction with tyrosine [48]. Chlorine dioxide has been found to reduce the absorbance of Acid Chrome Violet K [49]. Spectrophotometric methods of determining CIO2 with the use of Chlorophenol Red have been proposed [50,51]. A scheme for analysing mixtures of Cf, CIO, CIO2, ClO.i, CIO4 , and CIO2 using spectrophotometric and other methods has been devised [52]. 

Determination of replaceable hydrogen in an unknown acid. If the unknown is a weak acid (e.g., KHP, acetic acid, or vinegar) you will be instructed to use phenolphthalein indicator (color change same as above). If it is a strong acid, you may use another indicator, such as chlorophenol red (color change from yellow to violet). 

Methyl red Methyl red sodium salt Chlorophenol red Hematoxylin Litmus extra pure Bromophenol red Bromocresol purple 4-Nitrophenol Bromoxylenol blue Alizarin 4.4 t- V ... 

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