Gas chromatography (GC) is a universal separation technique applicable to complex mixtures. The technique uses differences in volatility and analyte-column interaction to achieve the desired separation. GC is commonly used to analyze mixtures for identification and quantification. Various ancillary GC techniques, such as headspace/GC-MS, and other multidisciplinary techniques, are available to solve client problems. GC techniques encompass a wide range of analytical problems. A wide variety of special detectors is available for quantification and specific identification of various classes of compounds.
Gel permeation chromatography
Gel permeation chromatography (GPC), also known as size exclusion chromatography, is an analytical technique that determines the molecular weight distribution (MWD) of a polymer by virtue of its hydrodynamic volume. Molecular weight averages, such as Mn, Mw and polydispersivity, are also characterized by GPC. The size and shape of polymeric molecules determine physical and processing properties and are critical to producing a product with the desired performance characteristics. This technique applies to any solvent soluble polymeric material.
High-performance liquid chromatography
High-performance liquid chromatography (HPLC) as with GC, is a universal separation technique applicable to complex mixtures. This chromatographic technique uses different mobile phases and columns to achieve the necessary separation of polar, thermally labile, non-volatile and other analytes that cannot be analyzed by gas chromatography. HPLC is non-destructive and analytes can be isolated for further spectroscopic analysis. Very low detection levels are achievable and multiple detectors can be used in series to monitor specific analytes. A wide variety of detectors are used including electrochemical, variable wavelength UV/visible, diode array and mass spectrometers. These are used to measure electrochemically active compounds, high molecular-weight analytes and non-UV absorbing materials.
Classical wet chemistry
AS&T provides analytical testing using classical wet chemistry techniques that conform to procedures of the ASTM and the Society of the Plastics Industry. These procedures are applied to analyses of coating resins, plastics and composite materials.