Markes International, Ltd.

This application note presents an advanced analytical system for the sensitive detection of trace-level air toxics in humid ambient air samples, in accordance with US EPA Method TO-15A. The cryogen-free preconcentration and thermal desorption approach, coupled to GC-MS, delivers exceptional chromatographic performance even for highly volatile and polar compounds. The system meets the stringent detection limit requirements of the latest air monitoring regulations, with method detection limits as low as 0.7 pptv. This innovative analytical solution provides a robust, cost-effective platform for the reliable quantification of hazardous air pollutants, enabling compliance with regulatory standards.

This application note explores an efficient, helium-free method for continuous monitoring of ozone precursors in ambient air, aligned with EPA PAMS requirements. By using hydrogen as the carrier gas, this approach achieves faster run times, stable retention times, and effective separation of volatile organic compounds. A case study from New York City highlights the system's performance in urban air quality monitoring, capturing shifts in pollutant levels during periods of reduced traffic. With remote operability and cryogen-free functionality, this method offers a reliable and sustainable solution for real-time air quality analysis in both urban and remote environments.

This application note demonstrates the use of high through-put automated thermal desorption (TD) coupled with GC-MS/MS for comprehensive PFAS measurement in indoor air. The method enables accurate quantification of a wide range of PFAS compounds, including neutral and volatile species, down to ultra-trace levels. Applying this approach, the study profiled PFAS contamination across different indoor environments, from workplaces to residences. When using sampling chambers to test materials, the PFAS they release into the indoor air can be identified, along with quantifying the emission rate of such releases.

This application note outlines a cryogen-free approach to collect and analyse ozone-depleting substances (ODS) and halogenated greenhouse gases (GHGs) in 100% humidity ambient air. The system uses automated canister sampling, a Nafion dryer for water vapour management, and GC-MS with selected ion monitoring to quantify 34 target compounds. The method achieves detection limits in the 0.08-0.30 ppt range, with good linearity, precision, and accuracy, meeting international requirements for monitoring these critical substances. The cryogen-free design and ability to handle highly humid samples make this a flexible and efficient solution for industrial ODS and GHG monitoring worldwide.

This study demonstrates the performance of thermal desorption (TD) analysis for the monitoring of 'air toxic' compounds according to US EPA Method TO-17. The results show excellent precision, linearity, and low method detection limits for all 65 target compounds across a wide volatility range. Key capabilities highlighted include the ability to re-collect and re-analyse split samples, as well as determining safe sampling volumes through breakthrough testing. The application of TD-GC-MS for trace-level air toxics analysis is shown to be a robust and reliable technique, meeting the stringent requirements of the US EPA method.

This application note outlines an analytical approach that meets the stringent requirements of EPA Method 327 for monitoring ethylene oxide and other hazardous air pollutants. The key innovation is the ability to achieve the required sensitivity without the need for liquid cryogen cooling, enabling more cost-effective and productive monitoring. Highlights include a 10 ppt method detection limit for ethylene oxide, effective management of sampling bias and chromatographic interferences, and straightforward method transfer between laboratories. The flexible, cryogen-free preconcentration system enables large-volume sampling to boost sensitivity while simplifying operation, making it an attractive solution for implementing the new EPA method.

Trace-level analysis of VOCs in a tomato product using headspace extraction with large volume preconcentration (LVP) and multi-step enrichment (MSE)

This study demonstrates the Centri® sample extraction and enrichment platform’s unique multi-step enrichment feature to enhance the discovery of trace-level, packaging-derived contaminants in food and beverage samples by GC–MS.

This study demonstrates highly sensitive detection of residual fumigants in seeds and spices using MSE–HS–trap with GC–MS, achieving detection limits as low as 0.0018 mg/kg, well below EU regulatory limits. Excellent linearity (R² > 0.99), reproducibility, and throughput (40 samples/day) are achieved. Enhanced sensitivity with single-ion-monitoring (SIM) is also demonstrated for ethylene oxide and 2-chloroethanol.

Application note outlining the methodology for assessing significant levels of PFAS emissions from food contact materials under typical usage conditions. PFAS were detected across a range of temperatures for the items tested, with concentrations varying from 1 pg/g to over 6000 pg/g.

This study shows how GC–MS performance for the sampling of aroma compounds and off-odours in beverages can be enhanced by using techniques incorporating trap-based preconcentration. The first part of the study focuses on SPME, and how trapping and enrichment can improve peak symmetry, qualitative analysis and sensitivity. The second part of the study compares these methods against automated robe-based high-capacity sorptive extraction, which as well as being operationally robust, ffers improved recovery for higher-boiling compounds and an extended analyte range.

Download this comprehensive eBook titled "What is Thermal Desorption?" This resource provides a thorough introduction to the technique, highlighting its advantages and applications.

A single method using HiSorb extraction and GC-MS for detecting chlorophenols and odorants in water shows high sensitivity and can process 32 samples daily automatically.

Automated high-capacity sorptive extraction with GC–MS for screening wine, at ppb levels, for two yeast-derived spoilage compounds in wine.

Automated wine aroma profiling using sorptive extraction and GCxGC: This study uses headspace sorptive extraction with GCxGC–TOF MS/SCD, enhanced by Tandem Ionisation

GC×GC–TOF MS with thermal modulation used to provide detailed and sensitive characterisation of pyrolysis oil composition to identify possible contaminants.

Analysis of VPH in environmental samples by automated flow-modulated headspace–GC×GC–FID, for robust and efficient sample quantitation.

This study investigates the performance of a high-throughput automated thermal desorption instrument coupled to GC–MS/MS for PFAS analysis.

Automated, high-sensitivity analysis of residual fumigants for food safety testing by multi-step enrichment–headspace–trap (MSE–HS–trap) with GC–MS.

Evaluating the effect of storage and packaging on the volatile composition of soft drinks with immersive sorptive extraction & GC×GC–TOF MS.

Analysis of trace per- and polyfluorinated organic vapours in air using cryogen-free thermal desorption and gas chromatography–mass spectrometry.

A method to collect and analyse ozone-depleting substances & halogenated greenhouse gases in 100% humidity ambient air with a cryogen-free preconcentration–GC–MS system

Webinar Date/Time: Tue, May 14, 2024 10:00 AM EDT

Automated high-capacity sorptive extraction with GC–MS for screening wine, at ppb levels, for two yeast-derived spoilage compounds in wine.

Application note shows how thermal desorption GC–MS is used to monitor the release of PFAS during the application of aqueous film-forming foam (AFFF).

Demonstrating how commercially available TD equipment is used to monitor CF4 & other products of incomplete destruction (PIDs) resulting from PFAS removal technologies.

This study investigates the performance of a high-throughput automated thermal desorption instrument coupled to GC–MS/MS for PFAS analysis.

Measuring PFAS pollution in ambient air with TD–GC–MS/MS at concentrations low as 2 pg/m3. Each of 19 targeted compounds had linear calibration with high repeatability.

Webinar Date/Time: Tue, Oct 31, 2023 10:00 AM EDT

Air quality measurement: Continuous, cryogen-free on-line monitoring of PAMS in ambient air using hydrogen carrier gas using EPA PAMS method.