Facilities of the Molecular Biogeochemistry Group

• HPLC: UltiMate 3000, Dionex Softron GmbH, Germering, Germany
• MS: Orbitrap Elite, Thermo Fisher Scientific, Dreieich, Germany

High-performance liquid chromatography is used separate individual components of a complex mixture. The separated compounds are detected by mass spectrometry. The mass spectrometer is also used for direct injection of samples and their structure elucidation.

• HP5890 GC, Agilent Technologies, Palo Alto USA
• IRMS: Deltaplus XL, Finnigan MAT, Bremen, Germany

This Delta+XL instrument is coupled with a GC-combustion system for compound specific isotope analysis (¹³C/¹²C and ²H/H) from GC eluates. For simultaneous compound identification, 10% of the GC effluent is split off to a GCQ organic mass spectrometer. This instrument is hosted by IsoLab.

• HPLC: ThermoFinnigan LC-IsoLink system, Thermo Electron, Bremen, Germany
• IRMS: Deltaplus XP, Thermo Electron, Bremen, Germany

This HPLC-IRMS system is used for compound specific isotope analysis (¹³C/¹²C) of liquid samples (soil water, sugar extracts, chloroform fumigation extracts/soil microbial biomass, nucleic acids: DNA, RNA). Recent improvements have been the SEC hyphenation for isotope analysis of size classes of soil DOC and soil microbial biomass.

• Agilent Technologies, 7890A GC-System; 220 Ion trap MS

This GC-MS system is used for Identification of volatile and semi-volatile individual organic compounds in complex mixtures. Within the mass spectrometer the molecules are ionized. Once the sample is fragmented it will then be detected. The Structural determination of unknown organic compounds is accomplished by matching their spectra with reference spectra

• Agilent Technologies, Palo Alto USA

Gas chromatography is a technique for separating chemical substances that relies on differences in partitioning behavior between a flowing mobile phase and a stationary phase to separate the components in a mixture. A Flame ionization detector (FID) consists of a hydrogen (H₂)/air flame and a collector plate. The effluent from the GC column passes through the flame, which breaks down organic molecules and produces ions. The ions are collected on a biased electrode and produce an electrical signal. In our work group we use this equipment to separate and quantify mixtures of organic compounds like: PLFA, n-alkanes, PAH, among others.

• Agilent Technologies, 7890B GC-System

Separation and quantification of individual components can be performed using a gas chromatograph with flame ionization detection.

• GC: 6890 with Monitor FID, Agilent Technologies, Palo Alto, USA
• PFC: Preparative Fraction Collector, Gerstel, Mülheim an der Ruhr, Germany

The PrepGC is designed for automated collection of compounds or compound groups after gas chromatographic separation. The PFC-unit is equipped with six sample traps and one waste trap. This system works with a liquid N₂ trap cooling.

• Mettler Toledo

Thermogravimetric analysis is a method to detect changes in physical and/or chemical properties of materials. Therefore mass loss is measured as a function of increasing temperature/time. Information on physical and chemical phenomena, such as vaporization, sorption, desolvation, oxidation or reduction can be detected by this. We run our TGA with synthetic air and Argon and use it to analyze differences in the carbonaceous composition of soils.