Micromachined gas-chromatographic (GC) components in combination with high sensitivity MOX detectors and novel pre-concentration materials were utilized to develop a miniaturized, portable, stand-alone sub-ppb level monitoring system for aromatic volatile organic compounds (VOC). Using metal oxide semiconductor (MOX) gas sensors as detectors in a GC system, the intrinsic analytic selectivity of GC is exploited in a simplified architecture with on-board generated carrier gas. The work reported here includes the study of innovative pre-concentration materials, the micromachining of GC components and devices, the fabrication and characterization of complete system prototypes, and the development of application-specific control electronics. The results of both laboratory trials and successful real-world cross-validation with a reference analyzer are described.