S is for Sulfur
Sulfur is an element that can be particularly challenging to measure. Most labs have a dedicated instrument for its analysis because sulfur is known to be ‘sticky.’ That is, it tends to stay in the mass spectrometer and affect analysis of other elements later, so it’s not something that you just randomly measure and then go back to day-to-day work.
Sulfur isotopes are useful for understanding the origins of sulfide ore deposits, whether bacterial activity resulted in the growth of sulfide minerals, or if it came from some igneous activity deep within the Earth. Sulfur is also useful for tracking pollution in ecosystems, as the sulfur in acid rain may have a distinctive isotopic signature.