Novel Approach to the Elemental Analysis of Crude and Diesel Oil

Abstract

A novel approach to the elemental analysis of crude and diesel oil permitted preconcentration of trace elements is presented. An oil sample is continuously pumped through the rotating coil column as a mobile phase while an aqueous nitric acid solution is retained as a stationary phase. Two phases are kept well mixed and agitated but there is no emulsion on the interface at chosen conditions. Preliminary investigation of features of stationary phase retention of two-phase liquid systems (oil/oil products-aqueous solution) in rotating coil column has been shown. Special features of CCC give an opportunity to vary the volume of oil samples to be analyzed from 10 mL to 1 L or more. Trace metals are preconcentrated into 10 mL of stationary aqueous acidic phase which pumped out of the column for analysis can be easily determined with inductively coupled plasma mass spectrometry (ICP-MS) without additional sample preparation. Optimal concentration in the stationary phase of nitric acid for preconcentration of elements from oil by CCC has been investigated. Combination of CCC with ICP-MS gives the possibility to develop a rapid, reliable and accurate method of trace metal including rare earth elements (REE) determination in crude oils and oil products. Combination of preconcentration method by CCC and highly sensitive determination method (ICP-MS) for quantitative detection of the trace elements (without any additional sample preparation) has been suggested for the first time.