Development of a portable gas chromatograph–linear ion trap mass spectrometer with dual-stage cryogenic preconcentration for on-site analysis of atmospheric CFC-11, CFC-12, HCFC-22, and HCFC-141b

Despite regulatory bans on ozone-depleting substances (ODS) such as CFC-11 and CFC-12, recent atmospheric measurements have revealed unexpected emissions, potentially originating from legacy banks or unreported production. Conventional monitoring of ODS relies heavily on large, laboratory-based instruments, which are unsuitable for rapid, on-site source identification. In this study, we present a portable gas chromatograph-linear ion trap mass spectrometer (GC-LIT-MS) for on-site quantification of four representative ODS: CFC-11, CFC-12, HCFC-22, and HCFC-141b. The GC-LIT-MS integrates a dual-stage thermoelectric cooling (TEC)-based preconcentration system, enabling rapid temperature modulation, efficient sample preconcentration, and robust field operation. The external first-stage cryogenic preconcentration module comprises a single TEC chip, a heat-dissipating fan, and a control module, resulting in a compact and simple structure. This module can be further integrated into unmanned platforms such as drones or autonomous surface vehicles to enable on-site sampling in otherwise inaccessible locations. Key parameters, including column type (DB-WAX), sorbent composition (Carbopack B/Carboxen 1000), and thermal conditions, were optimized to achieve complete separation and quantification within 17 minutes. The method demonstrates excellent linearity (2-50 ppb, <i>R</i>² > 0.996), low detection limits (0.06-0.21 ppb), and good repeatability (RSD < 5.5%). Recoveries ranged from 97.98% to 113.56%. This portable GC-LIT-MS offers a sensitive, efficient solution for screening the emission of ODS, environmental enforcement, and real-time atmospheric monitoring.