This invention describes a sample collection method that could release and collect residues of explosives and other chemicals from a surface; the described method is implemented into a compact detection system that can be used as a “wand” for screening chemicals residues on a subject. The wand configuration includes multi-function for sampling and detecting multiple threads. The invention further describes a method of inspecting a subject using an interrogating apparatus in a sweeping motion; the near range closed loop particle sampling arrangement allows effective collection of particle and vapor residues from a targeted surface. The invention also describes a sampling and detecting apparatus for on-the-fly threat detection using compact ion mobility based detectors.