Introduction
Most Toxic Industrial Compounds (TICs) have some degree of volatility and therefore can result in hazardous emissions that are easily transported through the air, posing additional risks for workers and the public. The toxicity of a compound directly correlates with its Occupational Exposure Limit (OEL), with more hazardous substances having lower OELs. For example, Trichloropropane (TCP) has an OEL of just 5 ppb, underscoring the need for highly sensitive detection methods.
Several critical applications highlight the need for effective detection and monitoring:
- Leak Testing: Pipelines, often composed of numerous flanges, require rigorous leak testing. While initial leak testing is essential, continuous monitoring would be ideal, as factors like gasket failure, corrosion, mechanical damage, and thermal or mechanical cycling can cause leaks over time.
- Clearance Testing: Before servicing, parts need to be tested to confirm the absence of harmful compounds, ensuring safe handling.
- Dismantling Industrial Complexes: During the dismantling of industrial facilities, the release of residual toxic substances poses significant health risks to workers and the environment. Continuous monitoring of hazardous emissions is vital to ensure safety throughout the process.
Classical offline sampling followed by GC-MS analysis in a laboratory can cover a broader range of compounds with low detection limits. However, GC-MS is labor-intensive, time-consuming, and the results are only available the next day, and thus delays the feedback needed for rapid decision-making. Moreover, situations may change quickly and especially leaks can occur at any time, putting workers at risk.
In contrast, real-time monitoring offers immediate feedback and enables swift intervention to protect worker safety and prevent environmental contamination. However, currently no portable analyzers are available that can reliably detect a wide variety of hazardous compounds at low concentrations. Optical methods like NDIR and CRD are limited to small molecules such as Methane (CH4), Hydrogen chloride (HCl), and hydrogen sulfide (H2S).
Mass spectrometric (MS) methods offer numerous advantages, including the ability to detect a wide variety of compounds at low concentrations. However, quadrupole-based MS systems typically suffer from low mass resolution, which limits their specificity, and can take up to a minute to complete a full scan. This limitation is addressed by Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS), which combines high mass resolution and real-time detection, allowing for the identification of a broad range of compounds at sub-ppb levels. For instance, a full spectral scan with PTR-TOF-MS can be completed in less than 1 second while maintaining sub-ppb detection limits. Despite these capabilities, MS-based systems have traditionally been stationary, laboratory-based instruments designed primarily for scientific research.
In recent years, IONICON has advanced its PTR-TOF systems for industrial applications, emphasizing high stability, reliability, and ease of use. In a joint project between Olin and IONICON, the PTR-TOF system has been further modified specifically for real-time detection of hazardous volatile compounds in mobile settings, and has been deployed and tested in the field.