Rapid determination of zinc, calcium and lead in lubricating oil additives

• Published in: BUNSEKI KAGAKU Vol. 9; no. 6; pp. 486 - 489
• Main Authors: KITAMURA, Tetsuo, HASHIMOTO, Naotake
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo The Japan Society for Analytical Chemistry 1960; Japan Science and Technology Agency
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.9.486

A direct EDTA titration method using benzenemethylcellosolve-sample mixture has been developed by the authors for the determination of zinc, lead and calcium singly or in combination, in lube additives and blended oils. Namely, in case of single metals, zinc and lead are determined directly by titration with a standard solution of EDTA using EBT as an indicator, after a sample is dissolved in a benzenemethylcellosolve solvent. To determine calcium, conc. hydrochloric acid is added to the sample-solvent mixture and heated on a steam bath for about 5 minutes. After cooled, a measured excess of EDTA is added and pH adjusted to 910 with conc. ammonium hydroxide, then the excess of EDTA is titrated with a standard solution of magnesium chloride. For determinations of these metals in combination, the method is also successfully applicable using some supplemental procedures such as maskings, pH or indicator selections. However, this method can not be used for the determination of barium which also interferes with calcium determination. The method is rapid and has accuracies nearly comparable to those obtained by conventional gravimetric or ashing-EDTA titration methods.