Microwave Acid Digestion of Crude Oil Samples Using a New High Performance Vessel

Introduction

The analysis of metals in crude oil prior to refining is of vital importance to the oil refining industry. V and Ni, for example, can act as catalyst poisons affecting the distillation process while toxic elements such as As and Se must be monitored due to environmental concerns. Traditionally, microwave digestion systems have been limited to smaller sample sizes due to the amount of NO_x gases produced in the digestion process.

This application note will focus on the use of the CEM MARS 6 microwave digestion system using a recently introduced high performance vessel to better handle the gaseous digestion byproducts. A mix of crude oil samples and NIST 1634c (Trace Metals in Fuel Oil) will be prepared and analyzed for As, V and Ni. A One Touch Method™ was created with a target temperature of 240 °C and a 20 min hold.