Лако-красочные материалы — производство

Besides their major use in pressure-sensitive, thermal, and photographic recording materials, triphenylmethane leuco dyes are extensively used in biological and analytical applications. They are used for detection of hydrogen peroxide in medical diagnostic kits (e. g., glucose determination, by glucose oxidase), in biotechnology process control,124,125 in analysis of biological fluids, and in wastewater treatment plants.126

The color formation property is also used for detection of carboxylic acids,102 anionic surfactants by spectrophotometric method127 in the 0­1500 ppm range. This procedure is suitable for automation. Triphenyl- methane carbinol bases and leuco cyanides have found use in making photoresponsive polymers. UV irradiation of polymers containing triphenylmethane leuco bases produces intensely colored cations through photodissociation followed by recombination of the cation with counterions on heating. This property can be used to produce reversible photomechani­cal transfer material.128 An acrylamide gel with a triphenylmethane nitrile shows reversible photostimulated dilation effect.129 When irradiated, dye cation is formed allowing creation of osmotic pressure differentials, causing swelling of gel. When in the dark, the gel deswells to its initial size due to the re-formation of the leuco nitrile.

Hexa(hydroxyethyl)pararosaniline nitrile has been used in a chemical radiochromic dosimeter.130 Ferricyanide oxidation of leuco Crystal Violet to Crystal Violet dye finds use in detection of various heavy metals131 at trace quantities. Oxidation of leuco triphenylmethanes by chloramine-T is catalyzed by iodide and therefore is used for detection of iodide.132 On the other hand, the inhibition of the catalytic effect of iodide by some ions can be used for determining traces of Ag(I), Hg(II), Pd(II). In addition, the triphenylmethane leuco dyes, phenolphthalein or phenol red are used extensively as indicators in calorimetric and titrimetric determinations.