Patent ID: 7388108

Claim:
A method for analyzing an easily-polymerizable compound by (a) introducing a gas containing the easily-polymerizable compound into an analyzing apparatus through a sampling tube having an inlet and an outlet connected to a reactor, wherein the sampling tube is a double tube having an inner and an outer tube, and a heating medium is fed into the outer tube of the sampling tube; (b) analyzing the gas in the inner tube of the sampling apparatus; (c) after completing the analysis of step (b) stopping the introduction of gas into the inner tube of the sampling apparatus; (d) cleaning the sampling tube by flowing stream through the inner tube of the sampling tube from a downstream side of the sampling tube toward the reactor, and after the cleaning of step (c) and while analysis is stopped; and (e) flowing air or nitrogen gas through the inner tube of the sampling tube in a reverse direction of the gas sampled and analyzed.