Efficient Multidimensional GC Analysis of Complex Samples using Low Thermal Mass Column Modules

Analysts often encounter complex real-world sample types such as petroleum fractions or volatile polymer components. Resolving all individual compounds using a single chromatographic separation can be quite challenging. Coupling columns with different polarities (multidimensional GC) can signifi cantly improve the resolution of complex samples. We coupled two low thermal mass (LTM) GC column modules with…

Headspace Sampling Unit Combined with a Metal Oxide Sensor or Standard Detectors for Quantification of VOC Emissions from Beverage Cans or Other Packaging Materials

The quality of packaging materials used in the food and beverage industry must be controlled regularly in order to avoid negative effects on packaged products caused by emissions, e.g. VOC emissions from printing processes or from varnishes used on inner surfaces of the packaging material. Many companies have worldwide production sites, that may not all…

Direct Thermal Extraction with Automated Liquid Calibration for the Quantification of Analytes in Solid Matrices

Direct thermal extraction is a sensitive technique for the analysis of residual compounds in solid matrices such as polymers, films, powders, and fibers. This approach can be used for both qualitative identification of unknowns as well as quantification of trace components. Quantification of analytes is often performed based on off-line spiking of liquid or gaseous…

Versatile Automated Pyrolysis GC Combining a Filament Type Pyrolyzer with a Thermal Desorption Unit

This paper describes an automated pyrolysis system for gas chromatography (GC) based on a filament type pyrolyzer combined with a commercially available thermal desorption instrument, onto which the pyrolysis module is installed. Automated sample introduction for both pyrolysis and thermal desorption is performed using a commercially available autosampler. For pyrolysis of solid, liquid, or melting…

Rapid Automated Screening of Extractable Compounds in Materials for Food Packaging, Medical or Technical Purposes

This application note describes two automated methods for screening of extractable compounds from materials for food packaging, medical or technical purposes. The first method is based on automated liquid extraction performed by the GERSTEL MultiPurpose Sampler (MPS), the second involves thermal desorption of the material in question in the GERSTEL Thermal Desorption Unit (TDU). Both…

Extractables and Leachables Analysis of IV Bag Systems using Direct Thermal Extraction of the Materials and Stir Bar Sorptive Extraction of Aqueous Solutions coupled with Thermal Desorption Gas-Chromatography with Unit Mass and High Resolution Mass Spectrometric Detection

IV bag components were analyzed for extractables using direct thermal desorption/thermal extraction combined with a unit mass resolution GC/MSD system. The results were compared to those obtained for leachables by stir bar sorptive extraction of an aqueous simulant stored in the exact same type of IV bag, again combined with GC/MS determination of the leached…

Improving Thermal Extraction Method Reproducibility through Instrument Temperature Calibration in the Sample Position

The influence of variations in desorption temperature, desorption fl ow and sample preparation on VDA 278 analysis method [1] robustness and reproducibility is studied using a wide variety of samples from automobile interior materials: polypropylene (PP) granulate, polyurethane (PU) foam, leather, Duroplastic plastics and paint. It is shown that a temperature difference of just two…

Measurement of Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation Using an Automated Micro-Scale Chamber Coupled Directly with the Analysis System

An automated analysis system consisting of a dynamic headspace (DHS) system coupled with thermal desorption-Gas Chromatography/ Mass Spectrometry (TD-GC/MS) was used for fully automated microscale chamber material emission analysis of Spray Polyurethane Foam (SPF). Closed-cell and opencell SPF samples were analyzed for emissions of TVOCs and high boiling compounds such as, for example, fl ame…

Determination of Formaldehyde and VOCs in Wood-based Products using an Automated Micro-Scale Chamber

An automated micro-scale chamber method based on 2,4-dinitrophenylhydrazine (DNPH) derivatization and Tenax TA adsorption, for sampling formaldehyde, acetaldehyde, acetone, acrolein, as well as volatile organic compounds (VOCs) was developed. Following the sampling step, the Tenax TA tubes were immediately transferred to a thermal desorption (TD)-GC/MS system for analysis. The DNPH tubes were transferred to an…

Automated Online Desorption and Analysis of DNPH Derivatives of Formaldehyde, Acetaldehyde, and Related Carbonyl Compounds using a New Robotic Autosampler

The analysis of airborne aldehydes and ketones first involves collection of the analytes by passing air through a cartridge containing 2,4-dinitrophenylhydrazine (DNPH). As the air passes through the cartridge, the analytes react with the DNPH to form hydrazones which are immobilized on the cartridge. The cartridges are then eluted with solvent and the DNPH derivatives…

Automated Determination of Formaldehyde Emissions from Materials by On-Sorbent Derivatization and Thermal Desorption GC/MS

A new fully automated thermal desorption (TD)-GC/MS method was developed for determination of formaldehyde and other airborne carbonyls as well as VOCs for material emission testing. The method includes an automated in-situ derivatization agent loading step prior to every sampling step, thus blank values are avoided. Pentafluorophenylhydrazine (PFPH) was used as derivatization agent and was…

Direct Thermal Extraction Analysis of Food Packaging Material

This study describes the use of the GERSTEL MultiPurpose Sampler (MPS) fitted with a Thermal Desorption Unit (TDU) and a Cooled Injection System (CIS 4) PTV-type Inlet for the automated direct thermal extraction analysis of packaging for three different brands of crème-fi lled chocolate sandwich cookies, cheese-filled sandwich crackers and soft and chewy candy. Download…

Asphaltenes in Crude Oil

Electron Paramagnetic Resonance (EPR) measures the concentration and composition of free radicals in a sample. Samples can be either liquid, solid or gas. Free radicals are atomic or molecular species with unpaired electrons that can be highly reactive. There are also many stable free radicals, such as melanin in hair and ultramarine blue pigment. Many…

Studying Antioxidants in Lubricants with EPR

Asphaltene concentration can be easily measured by ESR once a calibration curve has been made. The calibration curve made using an asphaltene powder dissolved in toluene. The ESR spectra of the various concentrations of apshaltene powder used to make the calibration curve. Active Spectrum has software that will automatically measure the concentration of an unknown…

Hydrogen Content in Hydrocarbons

Refining of hydrocarbons and vegetable oils typically includes hydrogenation. In a refinery hydrogen consumption is a major cost issue, and percent hydrogen content is used as an important indicator of refining progress. Hydrogen content at the endpoint is one of the specifications that needs to be met for products like jet fuel and diesel. An…