Solid phase extraction (SPE) is one of the sample preparation methods most widely used by chromatographers, as demonstrated by the numerous published SPE methods found in the literature. Typically, a liquid sample is passed across an adsorbent bed to retain and concentrate target analytes and eliminate interference from the sample matrix. Alternatively, the adsorbent can…
Fruit and vegetable extracts that are produced following the well established QuEChERS method [1,2] typically contain a signifi cant amount of involatile matrix material. After several injections of such extracts into the GC, sufficient matrix residue will be present in the GC inlet liner to lower or sometimes even increase the response of certain pesticide…
One of the most important aspects of reducing pesticide exposure is monitoring of pesticide residues in foods. A number of analytical methods have been developed, many of them based on traditional liquid-liquid extraction in combination with GC-MS or LC-MS. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation methods have been developed to…
The number of cannabis containing products, such as extracts, tinctures, edibles, waxes and oils, available in the United States have increased significantly due to changes in state law and the 2018 Farm Bill. Cannabis concentrates are legally manufactured for both medicinal and recreational use and are quickly becoming the most commonly used products by consumers…
Packaging materials for foodstuffs or consumer usage must not alter the flavor or odor of the substance being packaged. Examples of packaging materials include the paper used to wrap cigarettes, the paper cartons used in orange juice or milk and the Polyethylene (PE) often used for caps to seal soft drink bottles. Sometimes, due to…
During the past decade, miniaturized and solvent-less sample preparation techniques based on sorptive extraction, e.g. solid phase micro-extraction (SPME), have proven to be simple, fast and environmentally friendly alternatives to LLE while maintaining or even improving sensitivity. In 1999, a new extraction technique known as stir bar sorptive extraction (SBSE) using stir bars coated with…
Low Thermal Mass (LTM) technology was developed by RVM Scientific and is now offered as a retrofit to existing Agilent 5890 and 6890 GCs by GERSTEL as the Modular Accelerated Column Heater (MACH). The technology involves combining any length standard capillary GC column, a Resistance Temperature Detector (RTD) based thermal measurement system, and a precision…
Routine analytical methods employing mass spectral analysis on a gas chromatograph are often plagued with long run times in order to achieve acceptable separations. The Modular Accelerated Column Heater (MACH) System from GERSTEL is easily retrofitted to the Agilent 6890 GC with Mass Selective Detection. MACH is based on Low Thermal Mass (LTM) technology, that…
Ultra-fast gas chromatographic methods for determination of the hydrocarbon oil index according to ISO 9377-2 were developed using a modular accelerated column heater (MACH). The column heater consists of a module that enables very fast and controlled heating of the capillary column. The speed of analysis for the hydrocarbon group eluting between C10 and C40…
A method for fast screening of pesticide multiresidues in aqueous samples using dual stir bar sorptive extraction (dual SBSE) – thermal desorption (TD) – fast GC/MS has been developed. Recovery of 82 pesticides – organochlorine, carbamate, organophosphorous, pyrethroid and others – for the SBSE was evaluated as a function of octanolwater distribution coeffi cients (log…
A method for characterization of airborne particles including the nanoparticles fraction with a diameter of 29-58 nm in roadside atmosphere has been described. The method consists of thermal extraction (TE) and comprehensive two-dimensional gas chromatography (GC x GC) with novel detection capabilities, including high resolution time-of-flight mass spectrometry (HRTOF-MS), and simultaneous selective and mass spectrometric…
Static (equilibrium) headspace sampling is commonly used for GC determination of volatiles in solid and liquid samples. Since this technique relies on the analyte partitioning between the sample and headspace and uses a fixed injection volume it may not provide adequate detection limits, particularly for higher molecular weight, higher boiling analytes, and for polar analytes…
A fast SPE-GC-ECD method for the analysis of PCBs in waste oil was developed. A complete profile was obtained following SPE with a 12 minute GC run-time using a modular accelerated column heater (MACH). Full automation of the sample preparation and analysis (except sample weigh-in) enables a daily throughput of 100 samples. A wide range…
Static (equilibrium) headspace sampling is commonly used for GC determination of volatiles in solid and liquid samples. Since this technique relies on the analyte partitioning between the sample and headspace and uses a small injection volume it may not provide adequate detection limits, particularly for higher molecular weight, higher boiling analytes and for polar analytes…
A novel stir bar sorptive extraction (SBSE) procedure termed sequential SBSE was developed. Compared to conventional SBSE, sequential SBSE provides more uniform enrichment over the entire polarity/volatility range for organic pollutants at ultra-trace levels in water. Sequential SBSE consists of a SBSE performed sequentially on a 5-mL sample first without modifier using one stir bar,…
The Deepwater Horizon oil rig explosion and the subsequent massive oil spill is expected to be the worst offshore oil catastrophe in United States history and is now beginning to impact fragile ecosystems, air and water quality, and food supplies. Protecting humans from consuming foods contaminated with oil, while minimizing economical impacts for fisheries, is…
Applicable for the determination of naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[a]pyrene in seafood tissues including finfish and shellfish. The method is expected to be applicable to alkylated PAHs and related compounds in similar matrices. Limits of quantitation were shown to be < 1ng/g. Download PDF
This paper describes an automated pyrolysis system for gas chromatography (GC) based on a fi lament 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…