Real-time detection of dangerous compounds

Most toxic industrial compounds are somewhat volatile and can produce hazardous air emissions, posing additional risks to workers and the public. The toxicity of a compound correlates directly with its occupational exposure limit (OEL), with more hazardous substances having lower OELs. Trichloropropane, for example, has an OEL of 5 ppb, highlighting the need for extremely sensitive detection strategies.

Multiple important applications underscore the need for effective detection and monitoring:

1. Leak test: Pipes, which often include many flanges, require extensive leak testing. While initial leak testing is critical, ongoing monitoring is optimal, as factors such as gasket failure, corrosion, mechanical damage, and thermal or mechanical cycling can cause leaks over time.
2. Proof of settlement: Parts must be tested before service to verify the absence of harmful compounds, ensuring safe handling.
3. Dismantling of industrial complexes: During the dismantling of industrial facilities, residual toxic substances are released, putting workers and the environment at a significant health risk. Continuous monitoring of hazardous emissions is critical to ensure safety throughout the process.

Classical off-line sampling followed by gas chromatography/mass spectrometry (GC-MS) analysis in a laboratory can cover numerous compounds with low detection limits. GC-MS, however, is labor- and time-intensive, and results are only available a day later, delaying the feedback needed for rapid decision-making. Situations can also change quickly and leaks can occur at any time, putting workers at considerable risk.

Real-time monitoring provides instant feedback and facilitates rapid intervention to protect worker safety and prevent environmental pollution. However, there are currently no portable analyzers available that can reliably identify many hazardous compounds at low concentrations.

Optical approaches such as non-dispersive infrared and cavity ring can only be used for small molecules such as methane (CH).₄), hydrogen chloride (HCl) and hydrogen sulfide (H₂S).

Mass spectrometric (MS) approaches have many advantages, such as the ability to identify a wide range of compounds at low concentrations. However, quadrupole-based MS systems typically have low mass resolution, limiting their specificity and potentially taking up to a minute to complete a full scan.

This limitation is addressed by proton transfer reaction time-of-flight MS (PTR-TOF-MS), which combines high mass resolution and real-time detection, enabling the identification of various compounds at sub-ppb levels.

It is possible to complete a full spectral scan with PTR-TOF-MS in less than a second while preserving sub-ppb detection limits. Despite these capabilities, MS-based systems have conventionally been stationary laboratory-based tools built primarily for scientific research.

IONICON has recently developed its PTR-TOF systems for industrial use, highlighting its high stability, reliability and ease of use. In a project between Olin and IONICON, the PTR-TOF system has been further advanced for the real-time detection of hazardous volatile compounds in mobile environments and has been deployed and tested in the field.

Figure 1. The operator checks the emissions of a fence using live data transmitted to a tablet screen from the mobile PTR-TOF instrument. Image credit: Olin

methods

IONICON has advanced its robust PTR-TOF system, a PTR-TOF 1000. This system detects hazardous compounds with a 100 meter long sampling line alongside an additional pump to preserve rapid sample transfer from distant locations in the analyzer.

IONICON’s Automated Measurement and Assessment (AME) software was specifically trained to identify a predefined list of hazardous compounds, but also tracks all airborne compounds, including those that are not have predefined in the list.

To further improve the mobility and adaptability of the system, the PTR-TOF was installed on a mobile platform together with Olin. This setup allowed the device to be placed close to the sampling sites. Data collected from the system was transmitted wirelessly to a tablet.

results

The system was configured on a simple yet powerful mobile platform, which allowed the PTR-TOF system to be deployed within the sampling radius of different points. The long sampling line, reinforced by an additional pump, facilitated the rapid transfer of gas samples, generating results in near real time.

Even high concentrations of “sticky” compounds, such as phenol, were quickly removed from the system, ensuring reliable and continuous monitoring without delays from residual contamination.

The real-time capability made it easier to scan specific points and “sniff,” which helped more accurately identify emission sources, such as leaks. Data transmitted to the tablet allowed direct feedback, allowing the operator to calibrate the sampling location in real time.

The handcart used as a mobile platform for this presentation proved effective, with its smooth wheels providing adequate shock absorption during transport. The PTR-TOF showed its robustness and suitability for the application.

In the next phase, OLIN aims to use the PTR-TOF with a multi-channel sampling unit in an electric vehicle, improving mobility and ensuring constant power to the system.

Figure 2. The operator locates the source of a broadcast using the live data transmitted to the mobile screen. On the left, the simple but effective mobile PTR-TOF platform can be seen. Image credit: Olin

conclusion

Real-time monitoring technology such as PTR-TOF is essential to identify numerous hazardous compounds at low concentrations. It facilitates rapid assessment and immediate feedback, greatly speeding up the process compared to conventional approaches. This capability is especially important for industrial applications, where timely detection is critical to safety.

In contrast to traditional leak testing, where pipes are pressurized with a probe gas such as helium, which requires process interruption, online leak testing allows for continuous in-process monitoring. Leaks can be identified by “smelling” process compounds directly without stopping operations.

The versatility of IONICON’s AME software, which operates in multiple modes and tracks a wide range of compounds, improves the system’s specificity for hazardous substances and reduces the occurrence of false positives.

Because a PTR-TOF spectrum captures the entire spectrum of identified compounds, the system can be easily calibrated to track new or emerging hazards.

Further technical improvements, such as the integration of the PTR-TOF with an electric vehicle platform, aim to improve mobility and facilitate continuous power supply during field operations. This sophisticated solution is important to protect workers and the public alike in environments where hazardous compounds are present while reducing disruptions to industrial processes.

This information has been obtained, reviewed and adapted from materials provided by IONICON Analytik.

For more information on this source, visit IONICON Analytik.