Issue 9, 2022

Ultra-trace Hg determination in crude oils by CV-ICP-MS: overcoming the limitations of sample preparation to determine sub-ppb levels

Abstract

A method was developed to determine Hg in crude oil at sub-ppb levels by cold vapor generation inductively coupled plasma mass spectrometry (CV-ICP-MS) after wet digestion in a microwave-assisted system with a pressurized cavity. Operational parameters for crude oil digestion were optimized, such as sample mass, nitric acid volume, digestion temperature, and the heating program, overcoming the current limitations of closed vessel digestion for this type of sample. The accuracy of the proposed method was evaluated by spike recovery experiments and using standard reference materials (SRMs) of crude oil (NIST SRM 2722) and residual fuel oil (NIST SRM 1634c). The optimized conditions (8 mL of concentrated HNO3, 270 °C, and a heating program of 85 min plus 20 min for cooling) led to complete digestion of up to 1.2 g of crude oil (API gravity ranging from 9.5 to 28.8). The carbon concentration and residual acidity in digests were about 3500 mg L−1 and 10%, respectively, which were considered suitable for CV-ICP-MS analyses. In addition, Hg recoveries ranged from 92 to 105% for all samples and both SRMs. By overcoming the limitations for digestion of a relatively higher sample mass of crude oil (1.2 g), the proposed method enabled us to obtain a very low limit of detection (0.16 ng g−1). It is important to mention that this study reports the highest sample mass of crude oil feasible to be digested using closed vessels, thus contributing to determine sub-ppb Hg levels, as required by the industry.

Graphical abstract: Ultra-trace Hg determination in crude oils by CV-ICP-MS: overcoming the limitations of sample preparation to determine sub-ppb levels

Supplementary files

Article information

Article type
Technical Note
Submitted
17 мај 2022
Accepted
27 јул. 2022
First published
17 авг. 2022

J. Anal. At. Spectrom., 2022,37, 1799-1805

Ultra-trace Hg determination in crude oils by CV-ICP-MS: overcoming the limitations of sample preparation to determine sub-ppb levels

G. T. Druzian, M. S. Nascimento, R. S. Picoloto, M. F. Mesko, E. M. M. Flores and P. A. Mello, J. Anal. At. Spectrom., 2022, 37, 1799 DOI: 10.1039/D2JA00169A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements