Abstract
It has been established that a new filament loading scheme for lead isotopic analysis using thermal ionization mass spectrometry, so called “bead method,” which gives stable ion beam and high reproducibility. Two minor modifications to this scheme are presented in this paper; finer colloidal silicic acid is used instead of silica-gel, and flash heating is performed in nitrogen environment to prevent excess oxidation of filament. We report lead isotopic compositions of the NIST lead standard SRM 981, BCR-1, and GSJ standard rock samples using the present method.
