Simultaneous Multi-element Trace Analysis of Foodstuffs with TXRF

Total reflection X-ray fluorescence (TXRF) analysis has proven its capabilities in many different fields. The major advantages of the method are that it allows simultaneous multi-element detection and quantification down to the ppb range, using a highly sensitive spectrometer as the unique Bruker S2 PICOFOX is. Additionally, TXRF analysis shows no matrix effects, requires minimal sample amounts and almost no preparation effort. This article looks at recent application tests done with the S2 PICOFOX on foodstuffs, especially plant material.

Trace element analysis of plant material

The analysis of trace elements in plant material is necessary for several reasons. For instance, plants can accumulate toxic elements like heavy metals and, thus are intermediate reservoirs through which these toxic elements from soil, water and air can be transferred to living organisms via the food chain. On the other hand, plants can also be valuable sources for vital trace elements.

The most common analytical techniques for macro and trace element analysis are inductively-coupled plasma optical emission spectroscopy (ICP-OES) and inductively-coupled plasma mass spectroscopy (ICP-MS). However, the organic matrix of plant materials may cause analytical bias and block the sample introduction systems if not fully dissolved. For the decomposition of plant material laborious and time-consuming procedures are required.
TXRF spectroscopy can be an alternative or complementary analytical technology for raw materials and finished products in food processing. In order to test the possibilities and restrictions of TXRF spectroscopy, certified reference plant materials were analyzed with the S2 PICOFOX. Results show that the system provides results fast and reliably. The findings have been compiled in a lab report, which can be sent on request.

AOAC workshop

Another good opportunity to learn more about the S2 PICOFOX and its application to food analysis is the AOAC International (Association of Official Analytical Chemistry) annual meeting in Orlando, FL from September 26 to 29. It will host scientific sessions and several symposia. We would like to invite you to the XRF session “XRF for Screening of Foods, Nutritional Supplements; capabilities, use and limitations. The symposium will cover uses of XRF (with focus on TXRF) from lab to field with respect to inorganic element determination (contaminants) in food and dietary supplements. The symposium is aimed to increase the knowledge in the application of XRF analysis on foods, nutritional supplements and in the nutraceutical segment. More information on the meeting may be found under http://www.aoac.org/meetings1/124th_annual_mtg/main_2.htm.