The need for a rapid and reliable method for the determination of residual solvents has become significant due to the toxicity of residual solvents in drug substances and drug products 1. The determination of residual solvents in drug substances, excipients or drug products is known to be one of the most difficult and demanding analytical tasks in the pharmaceutical industry.
Bromate Solutions of bromates acidified with nitric acid 1 in 20yield a white, crystalline precipitate with the addition of 2 or 3 drops of silver nitrate TS, which dissolves by heating. A pale yellow precipitate is produced with the addition of 1 drop of sodium nitrite TS.
Solutions of bromates acidified with nitric acid 1 in 20produce a yellow to reddish brown colour with the addition of 5 or 6 drops of sodium nitrite TS.
With the addition of 1 ml of chloroform and stirring, the chloroform layer becomes a yellow to reddish brown colour. Bromide Free bromine is liberated from solutions of bromides upon the addition of chlorine TS, dropwise.
When shaken with chloroform, the bromine dissolves, colouring the chloroform red to reddish brown. A yellowish white precipitate, which is insoluble in nitric acid and slightly soluble in ammonia TS, is produced when solutions of bromides are treated with silver nitrate TS.
Calcium Insoluble oxalate salts are formed when solutions of calcium salts are treated in the following manner: A white precipitate of calcium oxalate forms upon the addition of ammonium oxalate TS. This precipitate is insoluble in acetic acid but dissolves in hydrochloric acid.
Calcium salts moistened with hydrochloric acid impart a transient yellowish red colour to a non-luminous flame. Carbonate Carbonates and bicarbonates effervesce with acids, yielding a colourless gas carbon dioxide which produces a white precipitate immediately when passed into calcium hydroxide TS.
Cold solutions of soluble carbonates are coloured red by phenolphthalein TS, whereas solutions of bicarbonates remain unchanged or are slightly changed.
Chloride Solutions of chlorides yield with silver nitrate TS a white, curdy precipitate which is insoluble in nitric acid but soluble in a slight excess of ammonia TS.
Chlorine, recognizable by its distinctive odour, is evolved when solutions of chloride are warmed with potassium permanganate and dilute sulfuric acid TS.
Copper When solutions of cupric compounds are acidified with hydrochloric acid, a red film of metallic copper is deposited upon a bright untarnished surface of metallic iron. An excess of ammonia TS, added to a solution of a cupric salt, produces first a bluish precipitate and then a deep blue-coloured solution.
Solutions of cupric salts yield with potassium ferrocyanide TS a reddish brown precipitate, insoluble in dilute acids.
Ferric salts Potassium ferrocyanide TS produces a dark blue precipitate in acid solutions of ferric salts. With an excess of sodium hydroxide TS, a reddish brown precipitate is formed. Solutions of ferric salts produce with ammonium thiocyanate TS a deep red colour which is not destroyed by dilute mineral acids.
A dark blue precipitate is formed. Ferrous salts Potassium ferricyanide TS produces a dark blue precipitate in solutions of ferrous salts. This precipitate, which is insoluble in dilute hydrochloric acid, is decomposed by sodium hydroxide TS.
Solutions of ferrous salts yield with sodium hydroxide TS a greenish white precipitate, the colour rapidly changing to green and then to brown when shaken. Iodide Solutions of iodides, upon the addition of chlorine TS, dropwise, liberate iodine which colours the solution yellow to red.
Chloroform is coloured violet when shaken with this solution. The iodine thus liberated gives a blue colour with starch TS. Silver nitrate TS produces in solutions of iodides a yellow, curdy precipitate which is insoluble in nitric acid and in ammonia TS.
Iron Solutions of ferrous and ferric compounds yield a black precipitate with ammonium sulfide TS. This precipitate is dissolved by cold dilute hydrochloric acid TS with evolution of hydrogen sulfide.QUANTITATIVE DETERMINATION OF ETHANOL IN WINE BY GAS CHROMATOGRAPHY B.
STACKLER and E. N. CHRISTENSEN Presented at the Annual Meeting of the American Society of Enologists, June 21, , San Diego, California. Gas chromatographic determination of water in natural products by reaction with 2,2-dimethoxypropane.
Nouri Y. Mary.
Abstract: Analysis of ethanol and water in consumer products is important in a variety of processes and often is mandated by regulating agencies.
A method for the simultaneous quantitation of ethanol and water that is simple. The conditions depends on the column type, length, etc., but in generally, if you inject pure ethanol onto the column you will see the retention . Quantitative Analysis by Gas Chromatography: Determination of an Equilibrium constant Introduction: Chromatography is often used for quantification analytes.
In this experiment the reaction between ethyl methanol in one and methyl acetate and ethanol will be the other. At equilibrium the concentrations of.
QUANTITATIVE DETERMINATION OF ETHANOL IN WINE BY GAS CHROMATOGRAPHY B. STACKLER and E. N. CHRISTENSEN Presented at the Annual Meeting of the American Society of Enologists, June 21, , San Diego, California.
Gas chromatographic determinations of ethanol, methanol, and acetone have been reported in one study with suboptimal accuracy and 1-propanol as internal standard. 11 Since 1-propanol can be found in the post-mortem blood sample, alternative internal standards have been recommended.
12 We present an easy and rapid GC method .