New insights into the source of the boron memory effect and implications for accurate boron isotope measurements.

Rationale: The boron (B) memory effect is a concern for B isotope analysis in inductively-coupled plasma mass spectrometry and a potential cause of poor data comparability between laboratories. It is widely assumed that the memory resides in water droplets on the surface of the spray chamber. However, even without the use of the spray chamber, background subtractions are still required to generate accurate data, therefore additional causes for the memory effect exist, which are investigated here.