ASSESSMENT OF THE ACCURACY OF THE DETERMINATION OF LOW-LEVELS OF SODIUM IN FUSED BEADS

In an earlier study, the accuracy of the determination of Na2O below a bout 0.5% (m/m) in samples prepared as fused beads was found tea be po or with an RMS of 0.14 and a k factor of 0.11. Three possible sources of this inaccuracy were studied, and an improvement to an RMS of about 0.025 and a k factor of 0.025 was achieved by a combination of more c areful determination of spectral overlap correction coefficients, allo wance for crystal fluorescence in tbe setting of the pulse height sele ctor and, most important, the preparation of new 'clean' beads. A comp arison of the performance of a W-Si synthetic multilayer (PX1) and TIA P for the determination of Na2O in fused beads has emerged from this s tudy. (C) 1997 by John Wiley & Sons Ltd.