LC-MS Analysis of Low-Molecular Weight Cationic Compounds

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.