Determination of Silicon, Iron, and Vanadium in Petroleum Coke by Microwave Digestion-Microwave Plasma Torch Atomic Emission Spectrometry

Abstract

Using microwave plasma torch (MPT) as an excitation light source, argon as support gas, the sample solution was introduced into plasma by pneumatic nebulization system. The determination of silicon, iron, and vanadium in petroleum coke by microwave plasma torch atomic emission spectrometry (MPT-AES) was studied. The experimental conditions were optimized and chosen. The effects of coexistent ions on silicon, iron, and vanadium emission signal were investigated in detail. The detection limits for silicon, iron, and vanadium were 0.040 μg/mL, 0.022 μg/mL, and 0.052 μg/mL, respectively. Linear dynamic ranges were 0.2–6 μg/mL, 0.1–100 μg/mL, and 0.2–100 μg/mL, respectively. The addition recoveries were in the range of 95.8%–105.0%. Petroleum coke samples were digested in the sealed vessel by a microwave digestion system. The optimum parameters for microwave digestion were studied and selected. The method of microwave digestion is a useful, time-saving technique and can reduce total sample preparation time. The result shows that the method is effective in detecting silicon, iron, and vanadium in petroleum coke and has the advantages of accuracy, easy operation, high automation, and low operation cost.

Keywords:

• iron
• microwave digestion
• microwave plasma torch atomic emission spectrometry
• petroleum coke
• silicon
• vanadium

ACKNOWLEDGMENTS

We wish to thank the authors and peer reviewers for their timely contributions to this article. We would also like to thank the editors, Dr. James and his colleagues, for their support.