Determination of Halogens and Sulphur in Complex Matrices - - Chromatography Online
Determination of Halogens and Sulphur in Complex Matrices

The Column
Volume 12, Issue 10, pp. 1217

Photo Credit: Martin Diebel/Getty Images
This article presents a method that combines combustion digestion and ion chromatography into a single analysis (combustion ion chromatography [CIC]) making it possible to detect halogens and sulphur in complex matrices. The method is suitable for use in a wide range of application areas.

Table 1: A selection of international standards that recommend combustion ion chromatography as a means of determining the halogen and sulphur content in flammable samples.
There are a number of different methods available to determine fluorine, chlorine, bromine, iodine, and sulphur in flammable substances. The majority of these are based on independent analysis steps, beginning with sample digestion using high-temperature combustion followed by halogen and sulphur analysis. As an alternative, combustion digestion coupled with ion chromatography (CIC) combines sample digestion and analysis in one step. CIC can be performed on a wide range of sample types regardless of whether solid, liquid, or gas. The only condition is that the sample has to be flammable. In addition to the halogen and sulphur analysis processes discussed in this article, which are used in the plastics, power generation, petroleum, and fuel industries, CIC is also suitable for samples from the pharmaceutical, environmental, and food sector. It is for these advantages that many international standards refer to CIC when determining the presence of halogens and sulphur in complex matrices (Table 1).

CIC Method Principles

Figure 1: Effect of 90 mg/L hydrogen peroxide in the absorption solution. Red: once with in-line matrix elimination; Black: once without.
Combustion: Combustion takes place in the presence of steam, which ensures that the gaseous halogen and sulphur compounds (HX, X2, SOx) are quantitatively collected by the absorption solution. Adding hydrogen peroxide to the absorption solution (for example, 90 mg/L) ensures that all sulphur compounds are present in the form of sulphate, which is necessary for ion chromatographic detection. However, when hydrogen peroxide is added as an oxidizing agent it can result in various interference peaks that overlay the fluoride peak. With in-line matrix elimination, these interferences disappear and the fluoride peak can be evaluated again (Figure 1).

An optical sensor in the pyrolysis oven indicates the progression of the combustion and regulates the feed of the sample boat. This ensures complete combustion by similarly reducing the sample's oven dwell time.

Instrumentation: The combustion unit is from Analytica Jena, while the liquid handling and IC are from Metrohm. The software used was MagIC Net from Metrohm.


blog comments powered by Disqus
LCGC E-mail Newsletters
Global E-newsletters subscribe here:



Column Watch: Ron Majors, established authority on new column technologies, keeps readers up-to-date with new sample preparation trends in all branches of chromatography and reviews developments. LATEST: When Bad Things Happen to Good Food: Applications of HPLC to Detect Food Adulteration

Perspectives in Modern HPLC: Michael W. Dong is a senior scientist in Small Molecule Drug Discovery at Genentech in South San Francisco, California. He is responsible for new technologies, automation, and supporting late-stage research projects in small molecule analytical chemistry and QC of small molecule pharmaceutical sciences. LATEST: HPLC for Characterization and Quality Control of Therapeutic Monoclonal Antibodies

MS — The Practical Art: Kate Yu brings her expertise in the field of mass spectrometry and hyphenated techniques to the pages of LCGC. In this column she examines the mass spectrometric side of coupled liquid and gas-phase systems. Troubleshooting-style articles provide readers with invaluable advice for getting the most from their mass spectrometers. LATEST: Radical Mass Spectrometry as a New Frontier for Bioanalysis

LC Troubleshooting: LC Troubleshooting sets about making HPLC methods easier to master. By covering the basics of liquid chromatography separations and instrumentation, John Dolan is able to highlight common problems and provide remedies for them. LATEST: How Much Can I Inject? Part I: Injecting in Mobile Phase

More LCGC Columnists>>

LCGC North America Editorial Advisory Board>>

LCGC Europe Editorial Advisory Board>>

LCGC Editorial Team Contacts>>

Source: The Column,
Click here