Thursday, July 15, 2010

Portable X-ray Fluorescence

X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays. Besides measuring arsenic, it can be used to analyse other elements and chemicals like the investigation of metals, glass, ceramics, and building materials and for research in geochemistry, forensic science and archaeology. The following diagram shows the basic working principle of this process.

The amount of photon emitted will help us determine the concentration of the arsenic in the sample. A photon is a  discrete bundle of light energy.

Portable X-ray fluorescence is used to measure arsenic in dry solid samples, such as soil and dried sludge. The main interferents listed in this method were variations in particle size, moisture, and lead co-contamination.


-Measuring devices are normally portable

- It can directly measure arsenic in the soil without having to extract the soil from the ground.

- Can measure a wide variety of metals besides arsenic

- Flexible as it can be used for measuring arsenic in both liquid and solid samples.


-It is not suitable for the detection of low concentrations of arsenic especially in drinking water as detection is only accurate at gram per litre concentrations.

-results can be interfered when lead is present in the sample

-many models contain a radioactive source, which may cause health effects to the user if not properly handled. However, research efforts have proven that this radioactive source can be eliminated and replaced by a less harmful source.

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