Determination of phosphorus and zinc in lubricating oil additives
Tóm tắt
Methods are described for the semimicro-determination of phosphorus and zinc in lubricating oil additives, after combustion in a 1-litre flask filled with oxygen. The phosphorus method is based upon conversion of phosphate into yellow phosphovanadomolybdate and spectrophotometric measurement of its absorbance at 460 nm. Zinc is determined polarographically after conversion into the tetrahydroxozincate ion which yields, upon reduction at the D.M.E., a well-developed wave at a starting potential of −1,10 V vs. S. C. E. A variety of oil additive samples, with low phosphorus (ca. 1.0%) and zinc (1–2.5%) contents, was analysed satisfactorily.
Tài liệu tham khảo
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