Issue 4, 2023

Fluorine-selective post-plasma chemical ionization for enhanced elemental detection of fluorochemicals

Abstract

Elemental analysis of fluorochemicals has received renewed attention in recent years stemming from the increased use of fluorinated compounds. However, fundamental drawbacks of in-plasma ionization have hindered ICPMS applications in this area. Recently, we have introduced post-ICP chemical ionization for BaF+ formation using Ba-containing reagent ions supplied by nanospray, leading to major improvements in F detection sensitivity. Here, we present further insights into this post-plasma chemical ionization. First, we examine the effect of oxygen introduced into the plasma (a necessity for organic solvent introduction) on BaF+ ion formation. The results indicate that excess plasma oxygen leads to abundant HNO3 in the post-plasma flow, shifting ionization reactions toward BaNO3+ formation and suppressing BaF+ sensitivity. To amend this, we utilize reagent ions with other metal centers to impart selectivity toward F detection. Our investigations show that robustness of F detection in the presence of abundant HNO3 improves in the order Al3+ ≈ Sc3+ > La3+ > Mg2+ > Ba2+ as the metal center in the reagent ions, consistent with the stronger metal–F bond in the series. Sc-based ionization resulting in ScNO3F+ shows the best balance between sensitivity and robustness in the presence of nitric acid. Similarly, this ion shows an improved tolerance relative to BaF+ for a Cl-containing matrix where HCl interferes with ionization. Finally, we demonstrate a unique feature of post-plasma chemical ionization for real-time flagging of matrix effects via monitoring reagent ions. These findings provide significant improvements of post-plasma chemical ionization for elemental F analysis, particularly for online chromatographic detection where solvent gradients are utilized.

Graphical abstract: Fluorine-selective post-plasma chemical ionization for enhanced elemental detection of fluorochemicals

Supplementary files

Article information

Article type
Paper
Submitted
27 12月 2022
Accepted
30 1月 2023
First published
08 2月 2023

J. Anal. At. Spectrom., 2023,38, 854-864

Author version available

Fluorine-selective post-plasma chemical ionization for enhanced elemental detection of fluorochemicals

J. L. Tanen, S. R. White, D. Ha and K. Jorabchi, J. Anal. At. Spectrom., 2023, 38, 854 DOI: 10.1039/D2JA00430E

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