Described herein are monitoring systems and methods, including for airborne molecular contamination (AMC), that combine a sampler, such as an impinger or sorbent tube with a real time analyzer, such as an ion mobility spectrometer (IMS) or optical particle counter. The system may allow for selective sampling in which the sampler is only exposed to the target fluid during periods in which the real time analyzer detects analytes, such as molecular contamination or particles, meeting particular criteria such the composition and/or concentration of analytes. The invention also includes impinger systems having a sampler reservoir comprising an anion leaching resistant material characterized by low anion leach rates in the presence of deionized water.