Benefits of radiello® Passive Sampling Devices

Importance of the Topic

Passive sampling for volatile and gaseous compounds is critical for environmental monitoring, occupational hygiene and indoor air quality assessment.
Traditional planar or axial samplers often suffer from limited sampling rates and capacity, restricting sensitivity in short- or long-term measurements.
The Radiello system addresses these limitations through its radial diffusive design which enhances uptake rate and capacity.

Objectives and Study Overview

This study evaluates the performance of Radiello passive samplers compared to validated active pumped sampling methods.
Key objectives include assessing correlation with standard methods, determining sampling capacity, and verifying sampling rates for common volatile organic compounds (VOCs) and gases.

Methodology and Instrumentation

Field trials conducted at a petroleum refinery compared 6–8 hour simultaneous sampling of BTEX (benzene, toluene, xylenes), n-hexane and MTBE using Radiello and pumped methods.
Radiello samplers incorporate a cylindrical diffusive body (e.g. RAD120 series), an adsorbent cartridge and a support plate (RAD121).
Available adsorbents include activated charcoal, graphitized carbon for thermal desorption, DNPH for aldehydes and specialized chemisorbers for NO2, O3, H2S, NH3 and other gases.
Samples were collected in ambient and industrial settings without active pumps, followed by laboratory desorption and analysis via chromatography or photometry following Fondazione Salvatore Maugeri protocols.

Results and Discussion

Strong linear correlations were observed between Radiello and pumped methods with R2 values of 0.91–0.95 for benzene, toluene, xylenes and n-hexane, and 0.80 for MTBE.
The radial design achieves diffusive sampling rates of 7–8 mL/min for benzene at 25 °C, outperforming traditional axial samplers.
High capacity tests showed Radiello can sample 1 600–3 050 L of air before back diffusion occurs, compared to only 34–49 L for equivalent charcoal tubes.

Benefits and Practical Applications

Radiello delivers higher sensitivity, lower detection limits, precise uptake rates and stable performance across diverse conditions.
Sampling rates remain constant regardless of air velocity, supporting short-term (15 min), 8-hour TWA and long-term (up to 30 days) monitoring.
The system is suitable for outdoor, indoor air quality and industrial hygiene studies, with reusable hardware and simple field handling.

Future Trends and Opportunities

Developing new adsorbent chemistries to expand analyte coverage and selectivity.
Integrating passive samplers with remote data logging and digital monitoring platforms.
Automating desorption and analytical workflows to enhance laboratory throughput and data consistency.

Conclusion

Radiello passive sampling offers a robust, high-capacity approach for monitoring a wide range of volatile and gaseous compounds, providing strong agreement with active methods, simplified operation and versatile environmental and occupational applications.