We present details of the operation and performance of a quadrupole mass spectrometer-based system developed for the extraction, separation, and high-precision measurement of noble gases dissolved in fluid samples. The relatively inexpensive quadrupole mass spectrometer system, employed with the isotope dilution technique, achieves a precision for He, Ne, Ar, Kr, and Xe abundances of ¿0.4%, ¿0.7%, ¿0.1%, ¿0.8%, and ¿0.9% respectively, as determined from analyses of mixed spike-air aliquots. The system has an overall accuracy of ¿0.6¿C on the noble gas temperature of a water sample, as determined by analyses of water samples air-equilibrated under controlled conditions. We describe improvements in calibration procedures and sample processing protocols that have led to these high-quality measurements.