Determination of low-level (sub-microgram) sulfur concentrations by isotope dilution multi-collector inductively couple plasma mass spectrometry using a 33S spike and internal normalization for mass bias correction

RATIONALE The certification of sulfur (S) in Standard Reference Materials™ by the National Institute of Standards and Technology (NIST) has been exclusively performed using isotope dilution thermal ionization mass spectrometry (ID‐TIMS). The ID‐TIMS measurement method is limited in its capability for low concentration measurements (