This study compares the measurement results of benzene, toluene, ethylbenzene, and xylene (BTEX) obtained using two gas chromatography (GC) instruments equipped with different detectors—mass spectrometry (GC-MS) and photon ionization detector (GC-PID)—and selected ion flow tube mass spectrometry (SIFT-MS) operated simultaneously in Korea. The main objective of this study was to evaluate the qualitative and quantitative accuracy of high-resolution volatile organic compound (VOC) measurement methodologies. Results showed that SIFT-MS overmeasured benzene concentrations by approximately a factor of two compared to the GC-based methods. For toluene, ethylbenzene, and xylene (C8 aromatic VOCs), the three instruments exhibited comparable performance, with good correlations among the measurements. Despite this, absolute relative percentage differences highlighted that GC-based instruments provided more accurate quantification than SIFT-MS. For benzene, GC-MS and GC-PID demonstrated higher measurement consistency and correlation, while SIFT-MS showed limited performance. In the case of C aromatic VOCs, all three 8instruments exhibited similar temporal trends, but GC-MS struggled to capture transient high concentrations compared to GC-PID and SIFT-MS, both of which demonstrated superior temporal resolution.