Identification of Components of Commercial Alkylsalicylaldoxime Based Reagents by GC–MS

Abstract

A simple gas chromatographic-mass spectrometric (GC–MS) method for the identification of components present in alkylsalicylaldoximes based metal extractants LIX860, LIX622, LIX622N, Acorga PT5050 and Acorga P5100 is described. These reagents have been developed for removing copper in hydrometallurgical processes. The extractants were analyzed by GC–MS in the Full Scan mode without any derivatization step. 5-Nonylsalicylaldoxime in the extractants LIX622N, Acorga PT5050 and Acorga P5100 and 5-dodecylsalicylaldoxime in the extractants LIX622 and LIX860 were found to be present as a mixture of alkyl isomeric compounds. The extractant Acorga P5100 also contains a large amount of p-nonylphenol isomers whereas LIX622, LIX622N and Acorga PT5050 contain tridecyl alcohol isomers. In addition, the presence of small amounts of alkylphenol isomers was detected in all LIX reagents. The GC–MS study has revealed that the major fragmentation ions of the alkylsalicylaldoximes can be classified into two types: the molecular ion less C _n H_2n+1 and the molecular ion less C _n H_2n+1 and water. Cleavage of the benzylic bond predominates, resulting in the base peak. The identified compounds have been classified in different types that show different base peaks and the possible structures of the alkyl groups based on the substitution of the alpha-carbon are proposed.