Abstract: Sampling systems for use on production lines with the capability to measure chemical components of a gas, vapor, or liquid sample taken from a product on the line and at a faster rate than the individual sensors alone are capable of. In one embodiment, the system detects the presence of insoluble hydrocarbons in the gas vapor present inside refillable water bottles that have been returned by the consumer. Each sampling system—apparatus—comprises two or more sub-systems each comprising: one or more sensors for performing a measurement of interest on a gas, vapor, or liquid sample, valves and a pump for directing the flow of samples, optionally an enclosed volume to hold the sample, and all under the direction of a control system. The sampling system also automatically acts on the measurement to detect when defective goods have reached a point where they can be ejected from the production line.