Field analysis of metals in marine sediments by X-ray fluorescence spectrometry (XFS) (CAT#: STEM-ST-0236-WXH)

Name: Field analysis of metals in marine sediments by X-ray fluorescence spectrometry (XFS)
SKU: STEM-ST-0236-WXH
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Introduction

Metal contamination in sediments is of environmental concern, since heavy metals, when bio-available, can be toxic to marine organisms and can bio-accumulate and move up the food-chain. Lead, for example, was identified as a major contaminant at about 30% of 546 evaluated Superfund sites, and arsenic, cadmium, chromium and zinc were each of concern at about 15% of the sites. These heavy metals, and others such as organotin and copper, can reach the estuarine and marine environments from many sources.

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Principle Applications Procedure Materials

Principle

XRF describes the process where some high-energy radiation excites atoms by shooting out electrons from the innermost orbitals. When the atom relaxes, that is, when outer electrons fill inner shells, X-Ray fluorescence radiation is emitted.

Applications

XRF is widely used as a fast characterization tool in many analytical labs across the world, for applications as diverse as metallurgy, forensics, polymers, electronics, archaeology, environmental analysis, geology and mining.

Procedure

1. Primary X-rays knock out an electron from one of the orbitals surrounding the nucleus within an atom of the material.
2. A hole is produced in the orbital, resulting in a high energy, unstable configuration for the atom.
3. To restore equilibrium, an electron from a higher energy, outer orbital falls into the hole. Since this is a lower energy position, the excess energy is emitted in the form of fluorescent X-rays.
The energy difference between the expelled and replacement electrons is characteristic of the element atom in which the fluorescence process is occurring – thus, the energy of the emitted fluorescent X-ray is directly linked to a specific element being analyzed.