Isotope Dilution Spark Source Mass Spectrometric Determination of Sulfur in Selected NBS Iron-Base Alloys

Author(s):  
PJ Paulsen ◽  
RW Burke ◽  
EJ Maienthal ◽  
GM Lambert
1953 ◽  
Vol 31 (10) ◽  
pp. 909-914 ◽  
Author(s):  
R. H. Tomlinson ◽  
A. K. Das Gupta

The mass spectrometer has been used for the estimation of trace quantities of rubidium and strontium. The isotope dilution technique developed by Aldrich has been extended so that 0.01% of rubidium and 0.0001% strontium have been analyzed with 100 mgm. of mineral. The use of small quantities for mass spectrometric determination allows the use of easily available fission strontium and rubidium. The radioactivity of the fission strontium also simplifies the chemical manipulation. No chemical separation from the mineral was required for the rubidium but the strontium was concentrated by ion exchange methods. Ages are presented for one lepidolite and two biotite minerals and their ages compared to those found by other methods. With one of the biotites the effect of weathering on the fractionation of rubidium from strontium has been studied.


1986 ◽  
Vol 32 (3) ◽  
pp. 536-538 ◽  
Author(s):  
S J Gaskell ◽  
L Sieckmann

Abstract Isotope dilution and mass spectrometry were used in two independent laboratories to determine cortisol in 15 plasma and serum pools used in the British and German national schemes for the external quality assessment of routine assays. For the concentration range 240-700 nmol/L, differences between the data obtained by the two laboratories were generally less than 4% but were approximately 7% in two instances. The discrepancies are nevertheless small in comparison with the bias observed for many routine assays.


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