Emergence of graphene-derived highly functional materials has transformed chemical and biological sensing. Several novel approaches utilizing chemical modification of graphene oxide (GO) were investigated and implemented using these materials in sensor fabrication for the detection of chemical analytes such as volatile organic compounds (VOC). The detection methods rely on using functionalization of modified graphene derivatives to target select analytes and produce a quantifiable, distinguishable electrical response. In this work, an in-house hydrothermal fluorination technique to synthesize fluorinated-GO (FGO) suspension was developed. The FGO material was drop coated in its solution phase onto interdigitated electrodes to create a chemiresistive gas sensor. An ultra-low-level detection of NH3 (~>2.26 ppm) was observed by the chemiresistive sensor which was extended to detect acetone and distinguish between their individual transient responses. The sensor system is fully integrated and miniaturized making it suitable for point-of-care, continuous health monitoring applications in exhaled breath testing.