Field Validation of New XRF Analyzers: Assessing Personal Exposure to Metals
Patrick Jeremy Parsons
A new Personal Exposure Analyzer (PEA) has been developed with NIH funding by X-Ray Optical Systems (XOS) and is based on a novel, non-destructive spectroscopic technique called energy dispersive (ED) monochromatic micro-X-ray fluorescence (MµXRF). This novel analyzer is designed for use in the field by non-laboratory trained staff to assess human exposure to multiple metals found in a variety of sample types (e.g., cosmetics, personal hygiene products) and matrices (e.g., liquid to solid) that an individual is exposed to or comes into contact with in a variety of environmental contexts (e.g., home or workplace).
Potential samples include:
- Consumable liquids (water, juice, tea, wine, salad dressings, and other condiments, etc.),
- Lotions and gels that are applied to the body (makeup, perfume, sun block, antiperspirant, shampoo, soap, toothpaste, and other personal hygiene products, etc.),and
- Food or ingestible material (spices, nuts, dietary supplements, pills, etc.) that can be easily crushed, powdered, or homogenized.
The primary goal of this project has been to validate exposure measurements obtained with this new analyzer under field conditions by deploying it in an ongoing biomonitoring study of mercury exposure in subjects of ethnic Chinese background living in the Capital Region of New York State. Between 25 and 30 personal environmental samples have been collected during scheduled home visits to participants, along with biological samples (urine, blood), and analyzed for metal content (including mercury).
The samples analyzed on site with the PEA are also analyzed for metal content in a reference laboratory using gold-standard methods of analysis. Results from the XRF (non-destructive) analyzer and the high-cost, gold-standard laboratory-based methods (destructive) are compared to the PEA results as part of the validation process. The validity, ease of use, and ruggedness of the analyzer is also assessed under field conditions to demonstrate its potential for use in other epidemiological studies.
This research has been carried out through a collaborative effort between scientific and engineering staff from XOS, and environmental analytical scientists from the New York State Department of Health's Wadsworth Center. The research team also builds on a growing collaborative relationship between Wadsworth Center scientists and environmental epidemiologists working with the NYS DOH's Center for Environmental Health in Troy, New York.
A new instrument for measuring one's personal environmental exposure to toxic metals using x-ray fluorescence (XRF) was developed with NIH funding by X-Ray Optical Systems (XOS). This research facilitates the validation of the personal environmental analyzer under field conditions using an existing study that is being conducted by the New York State Department of Health in Albany New York.