Gas Chromatographic Element Detector
for Halogens and Sulfur

Contents

• Features and advantages
• Functional principle
• Dedicated system software
• Analytical performance
• Scope of delivery
• Technical data

Features and advantages

• Plasma Emission detector with high resolution Echelle spectrometer
• multi-element gas chromatographic detector with high sensitivity and selectivity for sulfur and halogens chlorine, bromine, fluor, iodine
• detection limit for all elements < 10 pg/s
• linearity about 3-4 decades for all elements
• direct coupling from column to plasma cell - no transferline required
• simultanous detection of all elements
• long term stable plasma cell
• spectral data base
• stable pulse mode without starting-electrode, no sputtering effect
• simple and reliable use for routine analytics and research
• cross sensitivity to carbon < 1:20 000
• aircooled system without moving parts, installed on top of GC
• complete system "Made in Germany"

Functional principle

The detector was developed for the simultaneous and quantitative multi-element analysis of halogens and sulfur and is based on the excitation of atoms in a helium micro plasma at atmospheric pressure. The emission lines of the target atoms are continuously recorded by an echelle polychromator, which is directly adapted to the plasma cell. Due to the high energy of the pulsed plasma, all eluating molecules from the column are atomized in the plasma at temperatures of about 8000K and are emitting element-specific wavelengths.

The following part of the Echellogram shows two specific wavelengths for chlorine:

The simultaneous recording of strong and weak emission lines of excited atoms result in low detection limits, allowing a wide dynamic range and ensures the reliable analytical performance. During the gas chromatographic run all selected target elements can be recorded simultaneously. After the run all data can be transmitted in the .CDF format. In the following selected elements / wavelength traces are shown:

The EPED detector can be mounted on each GC, where the direct coupling of the GC capillary column with the plasma cell is of central importance. Reproducible and reliable results are mainly based on the transferlineless operation.

The following picture shows the EPED detector with high frequency power supply installed on a GC specific adaption plate:

Dedicated system software

All system settings can be done by the system software EPED. This software records all data of the complete GC-run, presents simultaneously the echellogram and transfers selected data in different file formats, e.g. .CDF.

The recording of all spectral data with high resolution enables a simple molecular mapping according to the retention time after the GC-run:

Analytical performance

The long term stability allows the use in laboratory and process analytics.

• Linearity bromoforme, trichloroethylene, methyljodine, octafluorotoluene, carbon disulfide, hexane
• Chromatograms chlorine, bromine, fluor, iodine, sulfur
• Reproducibility sulfide
• Equimolarity sulfur
• Screening methods of fluorinated substances
• Unknown fluorinated substances

Scope of delivery

• Plasma detector with integrated Echelle spectrometer
• 19" electronic and control unit, 2 m cable for plasma detector
• Laptop with system software EPED
• gas control unit for plasma gas He, additional gases: H2, O2, N2

Technical data

Development and adaption of the Echelle-polychromator has been realized in cooperation with :

The analytical evaluation of the EPED has been realized in cooperation with :