Evaluation of a new optic-enabled portable X-ray fluorescence spectrometry instrument for measuring toxic metals/metalloids in consumer goods and cultural products

Abstract

X-ray fluorescence spectrometry (XRF) is a rapid, non-destructive multi-elemental analytical technique used for determining elemental contents ranging from percent down to the µg/g level. Although detection limits are much higher for XRF compared to other laboratory-based methods, such as inductively coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectrometry (OES) and atomic absorption spectrometry (AAS), its portability and ease of use makes it a valuable tool, especially for field-based studies. A growing necessity to monitor human exposure to toxic metals and metalloids in consumer goods, cultural products, foods and other sample types, and while performing the analysis in situ has led to several important developments in portable XRF technology. In this study, a new portable XRF analyzer based on the use of doubly curved crystal optics (HD Mobile ® ) was evaluated for detecting toxic elements in foods, medicines, cosmetics and spices used in many Asian communities. Two models of the HD Mobile ® (a pre-production and a final production unit) were investigated. Performance parameters including accuracy, precision and detection limits were characterized in a laboratory setting using certified reference materials (CRMs) and standard solutions. Bias estimates for key elements of public health significance such as As, Cd, Hg and Pb ranged from -10% to 11% for the pre-production, and -14% to 16% for the final production model. Five archived public health samples including herbal medicine products, ethnic spices and cosmetic products were analyzed using both XRF instruments. There was good agreement between the pre-production and final production models for the four key elements, such that the data were judged to be fit-for-purpose for the majority of samples analyzed. Detection of the four key elements of interest using the HD Mobile ® was confirmed using archived samples for which ICP-OES data were available based on digested sample materials. The HD Mobile ® XRF units were shown to be suitable for rapid screening of samples likely to be encountered in field based studies.

Characterization of arsenic in dried baby shrimp (Acetes sp.) using synchrotron-based X-ray spectrometry and LC coupled to ICP-MS/MS

“…We used the "plastic" measurement mode with a measurement time of 3 minutes for quantitative results, as this had been previously validated for these types of samples. 28 As mentioned above, IAEA Algae-413 reference material (RM) was analyzed as a QC sample along with a boric acid blank at every run. Data processing was performed using the XOS "Solver", a proprietary program based on fundamental parameters method that is integrated into the portable XRF.…”

“…The performance of the portable XRF analyzer was previously described based on data from a number of CRMs including NIST SRM 2976 Mussel Tissue and NRC TORT-2 Lobster Hepatopancreas 28 . These particular CRMs were selected for this study due to their light biological matrix and similarity to the shrimp samples.…”

“…The novel aspects of this new portable XRF technology have been described previously. 28 Additional investigations of the dried baby shrimp were carried out at the Cornell University High Energy Synchrotron Source (CHESS), using SR-μXRF and Micro X-ray Absorption Near Edge Spectroscopy (μXANES) with a multi-array Si PIN detector (Maia). This 384-element X-ray detector was used to produce highresolution elemental images of the dried baby shrimp from XRF spectra, along with regional μXANES analyses that provided additional characterization on As.…”

The measurement of trace elements in human nails and nail clippings using portable X‐ray fluorescence: A review

“…50 The mono-energetic approach presents an advantage in terms of a high count rate and reduced background, which could be a benefit in achieving low detection limits in nail and nail clippings. This type of experimental approach has been illustrated in previous publications reporting on applications of XOS prototype, 27 pre-production XOS HD Mobile, 37 and final production XOS HD Mobile instruments. 37,41…”

“…A significant advance in pXRF technology, from the use of doubly curved crystal optics, has recently allowed sample excitation from a narrow-beam (~1 mm diameter) monoenergetic X-ray source. 37 This has raised the possibility of using pXRF for the measurement of trace elements from a single nail clipping. Such a technique was initially explored for As and Se in a phantom nail clipping, 38 and subsequently for Zn.…”