SYMPOSIA PAPER Published: 01 January 1958

8-Hydroxyquinaldine Extractions Applied to the Analysis of Metals


The new analytical reagent, 8-hydroxyquinaldine, reacts with many of the metal ions commonly encountered in analysis. The extraction behavior of 8-hydroxyquinaldine with some of these ions has been studied and has been applied in new methods for the determination of various elements in metallurgical products.

Of particular interest is the development of a new method for the determination of aluminum. Although 8-hydroxyquinaldine does not react with aluminum, it does react with many of the metal ions which normally interfere in the determination of aluminum. This property is utilized, after mercury cathode electrolysis, to eliminate small amounts of iron, copper, manganese, titanium, and other elements prior to the chloroform extraction and spectrophotometric measurement of aluminum 8-hydroxyquinolinate. For certain alloys which contain more than 0.1 per cent of aluminum, direct application of 8-hydroxyquinaldine can be made to eliminate inteferences.

This paper also includes a discussion of a new, rapid, and widely applicable spectrophotometric method for lead. This method consists of an initial extraction of lead by 8-hydroxyquinaldine from an alkaline cyanide-hydrogen peroxide medium. After an intervening extraction at pH 5 to eliminate traces of coextracted interferences, the lead 8-hydroxyquinaldinate is reextracted from a solution at pH 9.5. This method has been satisfactorily applied to a variety of standard alloys.

Author Information

Hynek, RJ
Experimental and Consulting Chemistry Laboratory, Allis-Chalmers Manufacturing Co., Milwaukee, Wis.
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Developed by Committee: E03
Pages: 36–42
DOI: 10.1520/STP39524S
ISBN-EB: 978-0-8031-5620-3
ISBN-13: 978-0-8031-5619-7