Carboxylic, aromatic, acids nitrosamines

Gas chromatography has been applied to the determination of a wide range of organic compounds in trade effluents including the following types of compounds which are reviewed in Table 15.15 aromatic hydrocarbons, carboxylic acids aldehydes, non ionic surfactants (alkyl ethoxylated type) phenols monosaccharides chlorinated aliphatics and haloforms polychlorobiphenyls chlorlignosulphonates aliphatic and aromatic amines benzidine chloroanilines chloronitroanilines nitrocompounds nitrosamines dimethylformamide diethanolamine nitriloacetic acid pyridine pyridazinones substituted pyrrolidones alkyl hydantoins alkyl sulphides dialkyl suphides dithiocaibamate insecticides triazine herbicides and miscellaneous organic compounds. 

Formulations usually contain a combination of different anodic and cathodic inhibitors. Commonly used are ortho- and polyphosphates, phosphonates, tannins, lignins, benzoates, silicates, chromates, molybdates, nitrites, nitrates, zinc salts, aromatic azoles, carboxylic acids, amides, amines, soluble oils, and oxygen scavengers, such as hydrazine and sulfites [3, 46]. Some of these substances (e.g. silicates) are employed predominantly in synergy with other inhibitors, whereas in other cases the combination of inhibitors may have adverse effects (e.g. nitrites and organic amines or amides may form carcinogenic nitrosamines at elevated temperatures). 

---