Determination Of Trace Elements In Petroleum And Its Products By Microwave Digestion-MPT-AES

In this paper,microwave digestion technology was used to treat crude oil,diesel oil and jet fuel samples,and the determination of trace elements in these three samples by microwave plasma torch atomic emission spectrometry?MPT-AES?was studied.The effects of the analytical spectral line wavelength,carrier gas flow rate,working gas flow rate and microwave forward power of MPT spectrometer on the atomic emission intensity of elements were investigated.The preliminary working conditions for the determination of lead,copper,manganese,zinc,nickel,vanadium and calcium were obtained.The acid effect and the interference of coexisting ions on the determination of elements were further analyzed.For manganese element which is easily disturbed by coexisting ions,lanthanum chloride sensitizer is added to increase its coexisting ion allowance.After optimizing the experimental conditions,the optimum working conditions for the determination of metal elements were obtained.The working curve,detection limit,precision and linear range of the metal ions to be measured were measured under the optimum working conditions.The detection limits of lead of copper,manganese,zinc,nickel,vanadium and calcium elements were25.30 ng·mL^-1,4.27 ng·mL^-1,4.27 ng·mL^-1,10.84 ng·mL^-1,3.09 ng·mL^-1,3.61 ng·mL^-1,3.61 ng·mL^-1,14.26 ng·mL^-1,14.26 ng·mL^-1,12.15ng·mL^-1,12.15 ng·mL^-1.The linearity range of these metal elements were0.07⁵0?g·mL^-1?0.01⁷0?g·mL^-1?0.03³0?g·mL^-1?0.02¹6?g·mL^-1?0.04⁴0?g·mL^-1?0.04¹0?g·mL^-1,respectively.After comprehensive consideration,microwave digestion was used to pretreat crude oil,diesel oil and jet fuel samples,Orthogonal test was arranged to determine the optimum microwave digestion conditions for the samples to be tested.The accuracy of microwave digestion-MPT-AES method for determination of trace elements in petrochemical products was verified by standard addition recovery test.The results showed that the recoveries of the elements to be determined were in the range of 92.50%¹08.00%,and the accuracy of the method was high.After a series of research and experiments,a new technology for the determination of trace elements in crude oil,diesel oil and jet fuel with traits of safety,convenience,low operating cost and high accuracy has been established.The new method opens up a new way for the determination of trace elements in petroleum and its products.