This article describes the method of determining trace metals in engine oil using the GTA-95 graphite tube atomizer. It points out that the analysis of oil samples using flame atomic absorption presents problems not encountered with aqueous samples. Electrothermal atomization has several advantages over flame methods, including the use of various diluting or extracting solvents, microlitre sample consumption, greater sensitivity, complete destruction of the sample matrix, and automatic standard preparation. The article also mentions the difficulties that may be encountered in preparing standards in oil.
The document describes a method for analyzing trace metals in engine oil samples dissolved in diisobutylketone (DISK). It highlights the advantages of electrothermal atomization over flame methods and addresses specific challenges with volatile elements like lead.
A key focus is the use of a pyrolytic graphite platform to prevent the loss of lead during ashing, which occurs when samples are dispensed directly onto the tube wall. The note provides instrumental requirements, standard preparation guidelines, and detailed temperature programs for determining lead using this platform.
| Analyzable Elements | Al, Cr, Cu, Ni, Pb and V |
|---|---|
| Solvent for Dilution | diisobutylketone (DISK) |
| Instrument Model | Agilent GTA-95 |
Lead loss is overcome by using a Pyrolytic Graphite Platform inserted into the furnace, which allows direct determination without lengthy acid digestion.
The pyrolytic graphite platform can reproducibly accommodate up to 40 µL of diluted sample.
An ash temperature of 500 °C (steps 3 to 5) was found to be optimum when using the platform.