The analytical apparatus is designed to perform in-line extraction, purification and measurement of 1012 to 1014 atoms of Ar from various K-bearing minerals. The sensitivity of the mass spectrometer is calibrated against the international K–Ar standard GL-O and determined with a 0.6 % (1σ) uncertainty. The average 40Ar/36Ar ratio of repeated air-standards through a 1-month period is 262.5 ± 0.36 (1σ), and its daily standard deviation never exceeds 1‰.
Geochronological standards MMhb-1 (520.4 ± 1.7 Ma, hornblende), LP-6 (127.8 ± 1.4 Ma, biotite), Taylor Creek Rhyolite (27.92 ± 0.04 Ma, TCR sanidine), Alder Creek Rhyolite (1.193 ± 0.001 Ma RAC-20 sanidine) and RMF96 (0.331 ± 0.002 Ma, sanidine) dated here at 529.7 ± 7.2, 130.1 ± 1.0, 29.13 ± 0.4, 1.189 ± 0.022 and 0.340 ± 0.006 Ma, respectively, are within or close to their published reference ages at the 1σ confidence level.
Recent high-sensitivity and high-resolution quadrupole mass filters, equipped with appropriate and high stability electronic equipments, provide compact and fast analytical alternatives to expensive magnetic-sector-type mass spectrometers for applications such as K–Ar geochronology.