Quantitative Trace Element Analysis of Micro-Samples by SIMS

Abstract

A number of researchers have applied secondary ion mass spectrometry (SIMS) in various areas of medical research. The potential of SIMS as an analytical tool in elemental microanalysis of biological specimens lies in its sub-part per million (ppm) elemental detection sensitivities and its ability to generate two and three dimensional distributions of the intensities of mass selected secondary ions. Established techniques such as inductively coupled plasma (ICP) and electron probe microanalysis (EPMA) are also capable of sub-ppm elemental detection limits. ICP detection limits are adversely affected as the sample volume decreases below 1 milliliter. The EPMA technique can achieve ppm detection limits with volumes in the 100 picoliter range but its detection limits do not decrease as the sample volume increases. SIMS combines excellent detection sensitivities with small sample masses (picogram) which makes it a very useful complementary technique to ICP and EPMA especially for minor and trace element level analyses in small volumes of biological fluids.