Advanced field screening technology for toxic chemicals will play a crucial role in treaty verification inspections for the new Chemical Weapons Convention (CWC). Because CWC treaty inspections are projected to take place on short notice and in many different locales worldwide, highly portable and self-contained chemical instrumentation packages can be especially valuable. Furthermore, the schedule of chemicals covered by the CWC encompasses a wide range of volatilities and chemical properties making the requirements for chemical instrumentation especially challenging. In response to these needs, the authors have developed an advanced handheld instrument based on an innovative, low thermal mass miniaturized gas chromatograph (GC) for rapid detection of treaty prohibited chemical weapons materials and precursor chemicals. This GC consists of an integrated capillary column, heater and temperature sensor which allows computer controlled temperature ramp rates as high as 10 C/s. Besides the GC, the instrument incorporates a miniature trap preconcentrator, miniature dual flame photometric detectors (FPD) for phosphorus and sulfur compounds, and advanced signal processing. The instrument is self contained, can detect a wide range of both volatile and semi-volatile compounds, and is designed for handheld operation during treaty inspections.