Abstract: A condensing apparatus is provided which can be used in gas chromatography measurements to determine N-methyl-2-pyrrolidone (NMP) content in polyimide prepreg. The condenser comprises a straight vertical section of thin-walled copper tubing followed by an ascending helical coil surrounding the straight section. The condenser is equipped with valves at the inlet and outlet which are capable of withstanding the combination of high and low temperatures as well as being resistant to damage by aggressive solvents. Liquid condensate accumulates at the bottom of the coil, making decanting easy. The condenser apparatus of the present invention yields very high collection efficiencies for volatile mixtures with a very wide range of boiling points. The condenser is very compact and lightweight and does not require any packing insulation to achieve the high collection efficiencies. Maintenance and cleaning are greatly simplified by the absence of packing.