Analysis of droplets from iso‐atomic solutions as a means of calibrating a transmission electron analytical microscope (TEAM)

SUMMARY This paper describes a spraying method of producing iso‐atomic droplets (≅3 μm diameter) of uniform size, distribution and chemical composition. These droplets were used to calibrate a TEAM system operated under given conditions, so that the relative sensitivity of the instrumentation for the elements Na, Mg, P, S, (Cl), K, Ca and Co (‘overall sensitivity factors’) could be determined. These factors (15, 40, 83, 90, (43), 104, 109, 100% respectively) were used to convert observed X‐ray intensity ratios from standard droplets to relative amounts of elements with a fair degree of accuracy (error generally less than ± 10%). It was proposed that the sampling and quantification methods could be applied for the absolute quantitative bulk‐analysis of fluids and tissues (after solubilization) with an introduced reference element, e.g. cobalt, and potentially to the study of relative elemental ratios in fluid microvolumes and in biological thin sections.