Handled XRF: A Solution for the Quick on-site Screening of Soil Contaminants

With the construction industry booming globally, especially in countries like China, the United States and India, many organisations are looking at faster ways to how they manage on-site contaminants screening for building sites.

Using a handheld X-ray fluorescence (XRF) analyser for soil screening helps site managers to considerably reduce analyses costs by reducing the number of samples sent to an off-site laboratory. Using an XRF analyser, they can quickly identify areas that require clean-up. With the ability to determine the elemental composition of soil samples, both qualitative and quantitative data can assist with decisions on further sampling strategy for the full assessment of soil quality. It also helps with monitoring remediation efforts.

Why invest in the latest handheld XRF analysers?

They’re fast, with results in seconds. Latest advances in detector electronics have significantly reduced testing time. You’ll be able to increase the number of tests you perform to make better-informed decisions and save time, as you’ll complete site screening surveys faster. There is no need to wait for lab results, which can take days or even weeks.

Handheld analysers are fully portable and usable in harsh environments and weather conditions. Compact and lightweight, some handheld XRF analysers, like the X-MET8000 from Hitachi High-Tech Analytical Science, are IP54 rated (protected against dust and splash water) and tested to MIL-STD-810G military standard for robustness.

They provide ‘point and shoot’ simplicity. With no or simple sample preparation required (there is no need for chemicals or reagents), using handheld analysers is really easy.

What you need to consider when buying a handheld XRF analyser

How detailed results do you need?
Great for using on-site, however, the limits of detection are not as low as techniques like ICP-OES, ICP-MS or flame-AAS. So handheld XRF cannot totally replace laboratory analysis.

What range of elements are you looking to measure?
The typical elements range for a handheld analyser is from Mg to U, depending on the application. It’s not sensitive enough though for very light elements such as Li and Be.

And how do you get great results with handheld analysers?

Whilst no or simple sample preparation is needed, the more effort you put into the pre-treatment of soil samples, the better the results will be. Remove debris, rocks, and flatten the area to test with a non-metallic object to smooth out the surface.

Dry out the samples as much as you can. You can use absorbent paper, and/or leave the sample to air-dry in a well ventilated area if needed as moisture above 10% will have a detrimental effect on the results accuracy. For best accuracy, sieve and/or grind the sample to obtain a fine particle size, and then place the powder in a thin sample bag or cup. You can then measure the bag or cup in a portable stand.

Measure a blank (e.g. SiO2 in a cup) at regular interval to check for contamination; change analysis window when needed. Measure a known soil check sample at regular intervals to verify accuracy and stability.

These are simple steps you can follow in the field to generate results you can trust.

Christelle Petiot is a Product Manager at Hitachi High-Tech Analytical Science. Hitachi High-Tech Analytical Science has a rich 40 year heritage of providing high-tech analysis equipment and services, designed to meet the tough challenges of a rapidly evolving industrial sector. For more information contact Hitachi-Hightech.