Sodium bisulfite developing agents

YeUowing of wool can occur during dyeing, depending on pH, temperature and time, and chlorinated wools ate especially sensitive. Bleaching agents that can be added to the dyebath have been developed based on sodium bisulfite and hydroxylamine sulfate (108). Addition of hydrogen peroxide to the dyebath after exhaustion can also be effective. 

Sodium bisulfite is often preferred in pyro developers and in Phenidone concentrates (Appendix 3 Pharmacopoeia Phenidone). Sodium bisulfite3 is often used in formulas that are divided into two solutions, as its weak acidity helps to inhibit the oxidation of the concentrated developing agent. When carbonate, contained in the B solution, is added to make a working solution, the bisulfite is immediately broken down into sulfite and bicarbonate, producing a useful buffering effect. 

NOTE 1 To help preserve the developing agents in Solution A, measure out the sodium bisulfite first and add a pinch to the water before the metol. Set the remainder of the bisulfite aside and add it in proper sequence. 

Epinephrine. Epinephrine (Adrenalin) finds use in a number of situations because of its potent stimulatory effects on both a- and /3-adrcncrgic receptors. Like the other catecholamines, epinephrine is light sensitive and easily oxidized on exposure to air because of the catechol ring system. The development of a pink to brown color indicates oxidative breakdown. To minimize oxidation, solutions of the drug are. stabilized by the addition of reducing agents such as sodium bisulfite. As the free amine, it is used in aqueous solution for inhalation. Like other amines, it forms salts with acids, for example, those now used include the hydrochloride and the bitartratc. Epinephrine is destroyed readily in alkaline solutions and by metals (c.g.. Cu, Fe, Zn), weak... 

Potassium metabisulfite (potassium pyrosulfite) is used as an antifermenting agent in breweries and wineries, and to bleach straw. Sodium bisulfite (sodium acid sulfite) is mainly used in pharmaceutical products, as disinfectant or bleach, and in the dye industry. Sodium sulfite is used in photographic developers, for fixing prints, bleaching textile fibers, and as a preservative in the food industry. 

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