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Simultaneous liquid–liquid extraction of dibenzyl disulfide, 2,6‐di‐ tert ‐butyl‐ p ‐cresol, and 1,2,3‐benzotriazole from power transformer oil prior to GC and HPLC determination
Author(s) -
Jaber Abdul Muttaleb Yousef,
Mehanemr Ahmed,
Abulkibash Abdalla Mahmoud
Publication year - 2012
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201100505
Subject(s) - chromatography , chemistry , mineral oil , detection limit , transformer oil , high performance liquid chromatography , benzotriazole , hexane , gas chromatography , analytical chemistry (journal) , transformer , organic chemistry , physics , quantum mechanics , voltage
2,6‐Di‐ tert ‐butyl‐ p ‐cresol ( DBPC ), dibenzyl disulfide ( DBDS ), and 1,2,3‐benzotriazole ( BTA ) are additives that may be found concomitantly in the oil matrix of power transformer. DBPC and DBDS act as antioxidants while, BTA is a corrosion inhibitor that protects copper conductors inside the transformer unit from corrosion. A powerful analytical method is, therefore, required to determine these additives at trace levels in the transformer oil. This work describes a unique single liquid–liquid extraction pretreatment step prior to the determination of the components by gas chromatography ( GC ) and high‐performance liquid chromatography ( HPLC ) techniques. The optimum volume ratio used in the pretreatment step was determined as 5:2:5 for mineral oil/ n ‐hexane/acetonitrile, respectively. Relatively, the method is simple and quick with a minimal use of solvents. Analytical results indicate that the method is relatively sensitive, accurate, and precise for each of the three components in fresh and used mineral oil. The calibration curves for the three components demonstrate a significant increase in sensitivities. Detection limits found were, 100 mg L −1 (0.01% w/v), 0.80 mg L −1 , and 2.04 mg L −1 for DBPC , DBDS , and BTA , respectively. The Student's t values determined at 95% confidence level indicate that there is no significant difference between the experimental means obtained by this method and the standard method for each component.