Paving the Way Towards a Safer Future With XRF Analysis

Could energy-dispersive X-ray fluorescence (EDXRF) spectrometers help improve our understanding of environmental health? In this article, Aaron Specht, assistant professor at Purdue University, and Stephen Williams, senior application specialist at Malvern Panalytical, explain how innovative XRF techniques for detecting heavy metals in dried blood spot samples are helping to create a cleaner, healthier world.

The dangers of toxic metal exposure: an ongoing public health concern

While some trace elements, such as iron and zinc, help keep us fit and healthy, others can have a devastating impact on our health and longevity.

Adverse effects from exposure to elements including cadmium, lead, arsenic and mercury can range from fatigue and reduced IQ levels to organ damage, cancers and even death.¹ The World Health Organization has estimated that lead poisoning alone contributes to 1 million deaths worldwide every year.²

Understanding the extent of this problem is crucial, as many sources of these heavy metals remain in common use in countries worldwide. For example, dangerous levels of toxic elements can be found in paints, water pipes and the byproducts of various industrial processes. Unsurprisingly, citizens of developing countries, which often have the most lenient industrial regulations, are among those hit hardest by environmental exposure to toxic elements.³

Identifying the sources of these elements and analyzing their impact on the human body and our environment is the mission of Aaron Specht, an assistant professor in the School of Health Sciences at Purdue University in Indiana, USA. In recent years, Specht has used EDXRF spectrometers to measure the heavy metals in our bodies in innovative and minimally invasive ways.

Investigating the link between toxic element exposure and Alzheimer’s disease risk

Specht is currently leading a study that aims to shine new light on the relationship between Alzheimer’s disease and related dementias (AD/ADRD) and four toxic elements: lead, mercury, arsenic and cadmium. This new study is one of the largest, most representative, and most racially diverse studies investigating the impact of toxic metal exposure on AD/ADRD in humans to date.

For this project, he and his team are using dried capillary blood spots collected from 15,000 individuals in the United States as part of a nationwide health and retirement cohort study sponsored by the National Institute on Aging. While the blood spots Specht and his team are testing were originally collected to map changes in the cohort’s DNA, the donors gave their consent for the samples to be used more broadly.

Aaron Specht and his colleague, Alison Roth, analyze toxic elements in dried blood spot samples using benchtop EDXRF systems. Credit: Malvern Panalytical.

Transforming lives with a fresh approach to toxic metals analysis

Technologies traditionally used to perform elemental analysis on blood samples, such as inductively coupled plasma-mass spectrometry (ICP-MS) are effective, but they also have their drawbacks.

For example:

• The price tag of each ICP-MS system unit can run into hundreds of thousands of dollars, with running costs also very high.
• The weight and size of ICP-MS systems mean they often require dedicated rooms.
• Operating and data analysis procedures can be complex and labor-intensive.
• Most ICP-MS systems require at least a milliliter of blood for reliable testing, making it difficult to leverage samples for additional analysis.
• To obtain the sample size required for effective testing, blood must be drawn from a vein by a trained phlebotomist — this can be a costly and uncomfortable procedure for many patients.
• Transporting, storing and preparing the samples also presents challenges.

But the greatest disadvantage is that this type of analysis compromises the integrity of the sample during the testing process, in most cases destroying it completely.

To address these challenges, Specht has turned to Malvern Panalytical’s Epsilon 4  EDXRF systems. These benchtop instruments analyze powder, liquid and solid samples without damaging them in any way. While a broad range of industries already use these XRF spectrometers, their use in environmental health has been limited to date.

Using Epsilon 4 EDXRF benchtop instruments, Aaron Specht can analyze dried blood spot samples without destroying them. Credit: Malvern Panalytical.

Exploring new possibilities for testing biological tissues

By working in collaboration with Stephen Williams and the Malvern Panalytical team, Specht has calibrated the Epsilon 4 systems to analyze samples, such as nail tissue and dried blood spots collected on filter paper – a process that could open a world of new possibilities for testing biological matrices.

The non-destructive nature of EDXRF increases the likelihood that researchers will gain access to existing sample collections, if suitable patient permissions are in place. Many organizations collect and store blood spots; for example, hospitals collect them from many newborn infants. Identifying whether toxic metals are present in these samples could help researchers demonstrate the true extent of exposure and highlight the critical need for programs to address these issues.

As well as being non-destructive, EDXRF has several other advantages. For instance:

• EDXRF testing only requires a small blood spot on filter paper, making sample collection easy, relatively pain-free and eliminating the need for trained phlebotomists.
• The purchase price and running costs of each Epsilon 4 are relatively low in comparison to other technologies.
• It’s easy to train people to use EDXRF – typically, training takes just one afternoon.
• With EDXRF, you can run multiple samples simultaneously – with the four Epsilon 4 units he is using for the study, Specht can test a minimum of 80 blood spots per day.
• The Epsilon 4 units are small and compact, meaning they are easy to transport, including to overseas locations.
• With EDXRF, you can measure other metals present in the samples at detectable levels, including zinc, iron and copper.
• EDXRF is accurate and reliable – a recent comparison study has shown alignment between data from venous blood samples analyzed with ICP-MS and dried blood spot samples measured using EDXRF.⁴

Finger-prick blood spots can be collected quickly, simply and non-invasively on a filter paper, without the need for trained phlebotomists. Credit: Malvern Panalytical.

Campaigning for a cleaner, healthier future

EDXRF technology offers a simple, compact and cost-effective solution for elemental detection in biological samples, with implications for expanded testing worldwide, particularly in low- and middle-income countries currently lacking elemental exposure surveillance programs.

Ultimately, by identifying sources of exposure, pinpointing affected communities and improving our understanding of the long-term impacts of toxic metal exposure, EDXRF blood spot analysis could significantly improve future prevention strategies.