As. Al-ammar et Rm. Barnes, Improving isotope ratio precision in inductively coupled plasma quadrupolemass spectrometry by common analyte internal standardization, J ANAL ATOM, 16(4), 2001, pp. 327-332
The common analyte internal standardization (CAIS) chemometric technique is
extended to improve isotope ratio precision obtained by inductively couple
d plasma-quadrupole mass spectrometry (ICP-QMS). A correction function for
isotope ratio measurement is derived from a relationship of mass sensitivit
y as a function of element mass after considering the degree of ionization
and isotopic abundance. An analyte isotope ratio correction factor can be d
etermined by simultaneously measuring several internal reference isotopic r
atios and the analyte. The CAIS approach corrects for isotopic mass bias an
d isotope ratio variation with sample matrix concentration. Isotope ratio p
recision is improved from about 0.4 to 0.05%, because long-counting times a
llow correcting mass bias and isotope ratio drift during extended data-acqu
isition periods. Isotope ratio accuracy is improved from 0.2 to 0.02%.