5- Nitrosalicylaldehyde reagent

The 5-nitrosalicylaldehyde reagent is prepared as follows. Add 0-5 g. of 5-nitrosalicylaldehyde (m.p. 124-125°) to 15 ml. of pure trietlianolamine and 25 ml. of water shake imtil dissolved. Then introduce 0-5 g. of crystallised nickel chloride dissolved in a few ml. of water, and dilute to 100 ml. with water. If the triethanolamine contains some ethanolamine (thus causing a precipitate), it may be necessary to add a further 0 5 g. of the aldehyde and to filter off the resulting precipitate. The reagent is stable for long periods. 

Nitrosalicylaldehyde reagent test. This test is based upon the fact that 5-nitro-salicylaldehyde and nickel ions when added to a primary amine produce an immediate precipitate of the nickel derivative of the Schiffs base. 

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