Preparation of volatile halogenated hydrocarbons reference material and development of analytical methods by dual-inlet internal-standard GC-MS and GC-ECD

In recent decades, environmental concern over volatile halogenated hydrocarbons (VHHs) in ambient air has grown significantly, driven by their widespread occurrence and potential risks to ecosystems and human health. Monitoring VHHs is essential to assess atmospheric pollution, enable risk assessment and guide regulatory decisions. However, as VHHs concentrations vary widely in ambient air, their accurate quantification necessitates multi-level reference materials (RMs) coupled with highly sensitive and precise analytical methods. Existing single-level RMs fail to cover the concentration gradients present in stack emissions, risking the absence of a traceability chain. Although GC-MS is a commonly used monitoring instrument, it suffers from signal drift (i.e., gradually decreasing response values) during experiments, which can compromise data accuracy. The study selected 14 VHHs that are under key monitoring in China, with concentrations relevant to current emission control requirements. The 14 VHHs RMs with a multi-concentration level ranging from 0.01 μmol/mol to 50 μmol/mol were first prepared using a gravimetric approach with reasonable grouping, separate weighing and final combination preparation. A novel dual-inlet internal-standard GC-MS analytical method and a GC-ECD analytical method were developed for the determination of the 14 VHHs RMs. The resolution, asymmetry and sensitivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy were validated. The results showed that both methods effectively separated the 14 VHH RMs, with LODs of 0.1 nmol/mol–1.51 nmol/mol for GC-MS and 0.02 nmol/mol–4.9 nmol/mol for GC-ECD. Both methods exhibited excellent linearity, with correlation coefficients >0.995 for all calibration curves. Regarding repeatability (RSD), the system, method, and intermediate variabilities were ≤0.75%, ≤0.90%, and ≤1.09% for GC-MS, and ≤0.66%, ≤0.82%, and ≤0.92% for GC-ECD. The results indicated that the developed VHHs RMs with the GC-MS and GC-ECD analytical methods were expected to be used for ambient air monitoring and stationary source emission monitoring. • 14 volatile halogenated hydrocarbons (VHHs) reference materials (RMs) were prepared for the first time. • A novel dual-inlet internal-standard GC-MS configuration and GC-ECD were developed to determine the 14 VHHs. • The GC-MS and GC-ECD method were validated, demonstrating their good performance. • The developed VHHs RMs with GC-MS and GC-ECD methods can be used for fixed pollution source exhaust gas monitoring.