scholarly journals Validation of new instrumentation for isotope dilution mass spectrometric determination of organic serum analytes

1999 ◽  
Vol 104 (2) ◽  
pp. 141 ◽  
Author(s):  
P. Ellerbe ◽  
C. S. Phinney ◽  
L. T. Sniegoski ◽  
M. J. Welch
Keyword(s):  
Isotope Dilution ◽  
Mass Spectrometric ◽  
Mass Spectrometric Determination ◽  
New Instrumentation

THE USE OF ISOTOPE DILUTION IN DETERMINATION OF GEOLOGIC AGE OF MINERALS

1953 ◽  
Vol 31 (10) ◽  
pp. 909-914 ◽  
Author(s):  
R. H. Tomlinson ◽  
A. K. Das Gupta
Keyword(s):  
Ion Exchange ◽  
Mass Spectrometer ◽  
Isotope Dilution ◽  
Chemical Separation ◽  
Mass Spectrometric ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Mass Spectrometric Determination

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.

Mass-spectrometric determination of serum cortisol: comparison of data from two independent laboratories.

1986 ◽  
Vol 32 (3) ◽  
pp. 536-538 ◽  
Author(s):  
S J Gaskell ◽  
L Sieckmann
Keyword(s):  
Mass Spectrometry ◽  
Quality Assessment ◽  
Isotope Dilution ◽  
External Quality Assessment ◽  
Serum Cortisol ◽  
Mass Spectrometric ◽  
External Quality ◽  
Mass Spectrometric Determination

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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