X-ray Fluorescence (XRF)

Overview

Source: Laboratory of Dr. Lydia Finney — Argonne National Laboratory

X-ray fluorescence is an induced, emitted radiation that can be used to generate spectroscopic information. X-ray fluorescence microscopy is a non-destructive imaging technique that uses the induced fluorescence emission of metals to identify and quantify their spatial distribution.

Procedure

1. Preparing the Silicon Nitride Windows

Use reverse tweezers to pick up a window (silicon nitride windows will shatter if dropped).
Place window onto a glass slide, flat side up.
Adhere small pieces of Scotch tape to the sides of the window, and use these to adhere the windows to the bottom of the culture dish.
Sterilize the windows in culture dishes with UV radiation. This can be accomplished with the auto-crosslink setting on a UV-crosslinking cabinet, followed by further UV i

Results

The X-ray fluorescence map of an adherent cell is shown in Figure 1. Each panel shows the distribution of a particular element (e.g., copper, iron, zinc, etc) over the cell. The panel labeled 's_a' shows the absorption of X-rays.

Figure 1. X-ray fluorescence map of an adherent cell.

Application and Summary

X-ray fluorescence imaging can be a useful tool in many fields including geosciences, forensic science, materials science, biology, and even in studying our cultural heritage. In materials science, it can help find defects in chips and catalysts made with metals. In cultural heritage work, it has been used to identify poisonous metals in the hair of famous dead people (e.g., Beethoven), and to identify the source of paints used in art. In biology, it is used to study the natural metals that perform important biochemistry