Authors: Miguel del Nogal Sánchez Paul Glanzer José Luis Pérez Pavón Carmelo García Pinto Bernardo Moreno Cordero
Publish Date: 2010/10/13
Volume: 398, Issue: 7-8, Pages: 3215-3224
Abstract
A sensitive method is presented to determine antioxidants 2 3 and 4tertbutylphenol 26ditertbutylphenol 3tertbutyl4hydroxyanisol 26ditertbutyl4methylphenol 1naphthol and diphenylamine in new and used lubricant oil samples Research was carried out on a GC device equipped with a headspace sampler a programmed temperature vaporizer and an MS detector unit The proposed method does not require sample treatment prior to analyses hence eliminating possible errors occurring in this step Sample preparation is reduced when placing the oil sample 20 g in the vial and adding propyl acetate 20 μL Solvent vent injection mode permits a preconcentration of the compounds of interest in the liner filled with TenaxTA® while venting other species present in the headspace Thereby both the life of the liner and the capillary column is prolonged and unnecessary contamination of the detector unit is avoided Calibration was performed by adding different concentrations of analytes to a new oil which did not contain any of the studied compounds Limits of detection as low as 057 μg/L 2tertbutylphenol with a precision lower or equal to 53 were achieved Prediction of the antioxidants in new oil samples of different viscosities 5W40 10W40 and 15W40 was accomplished with the previous calibration and the results were highly satisfactory To determine antioxidants in used engine oils standard addition method was used due to the matrix effect
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