Separation techniques at ECCD

Mixtures come in many forms and phases, e.g. mixtures of gases, gases in liquids or solids, mixtures of liquids or solids in liquids. Most of the individual substances in a mixture can be separated in ECCD. The kind of separation method depends on the type of mixture. If the separation technique is coupled to the right detector the analyte of interest can be also identified and quantified.

Separation techniques generate results like e.g. concentration and type of compound, separation of isomers, the charge distribution in polyelectrolytes, molar mass and its distribution, molecular architecture or chemical composition distribution in polymers. The choice of the detector is essential for achieving the desired detection limits or level of identification.

Sample preparation and analytical approach

Sample preparation is a key step in an analytical workflow. There are plenty of reasons for this statement. Sometimes, the matrix severely interferes with the analyte of interest. Then sample clean-up is the solution. In some situations, the analyte can be present in not-detectable amounts. In such a case sample pre-concentration, selective analyte isolation or the introduction of spectroscopically active tag considerably increases method sensitivity. The analyte can also be modified by e.g. silyl or methyl groups to enable single GC analysis of mixtures of volatiles and semi- to non-volatiles.

If the analyte itself is a complex structure (e.g. macromolecule) its break-down to small pieces or release of specific functional groups can enable its accurate identification or quantification.

Within ECCD we use our years of experience in serving the chemical industry to recognize the benefits and limitations of the technical capabilities and to choose a suitable approach for every request. Such an approach can involve a stand-alone technique or consist of a multi-analytical approach.

Facilities

Non-volatile small molecules

Liquid chromatography (both HPLC and UHPLC) with UV, RI, ELSD, CAD, FLD and MS detection
Analytic fraction collector
Capillary zone electrophoresis with reverse UV conductivity, or MS detection

Volatiles and gas analysis

Gas chromatography with FID, TCD, ECD, HID, and MS detection
Various injection options
Gas analysis
Gas chromatography with olfactory detection
Thermal desorption GC-MS
Selected ion flow tube mass spectrometry (SIFT-MS) with various sample introduction options
Catalytic breakdown unit

Macromolecules

Aqueous and organic size exclusion chromatography with triple detection, i.e. concentration (UV, RI), MALS, and viscosity detection
Pyrolysis GC-MS

Sample preparation and modification

Sample preconcentration techniques compatible with GC (e.g. thermal sorption, SPME, SBSE) and HPLC (SPE, freeze-drying, liquid extraction)
Derivatization of functional groups
Hydrolysis of macromolecules to elucidate monomer composition
Gas sampling techniques like specialized bags, cylinders or sorption tubes