ICP-MS for Detecting Heavy Metals in Foodstuffs

Table 1 presents the data generated for the elements outlined in the EC 1881/2006 regulation and for arsenic for the four CRMs. Due to the multi-elemental capacity of ICP-MS, a number of other elements were simultaneously quantified. The results obtained for the CRMs were in close agreement with the certified values, validating the method and the instrumentation for determining total elemental concentrations in foodstuffs.

A high LDR range was achieved, meaning that the major components of food such as phosphorous (P), sodium (Na), and potassium (K) could be determined in the same run as the minor elements such as Cd and Hg. A calibration of K from 10 parts per million (ppm) to 0.2% and a calibration of Hg from 50 ppt to 10 parts per billion (ppb), both acquired in the same experiment, demonstrate the advantage of the high LDR of ICP-MS (see Figure 2).

Table 2 shows the quantitative data for a larger number of analytes and for two of the food CRMs. For all analytes, the measured and certified concentrations are in close agreement. This demonstrates the power of ICP-MS to measure simultaneously at sub-ppb level (Hg, silver, uranium) and percentage level (Na, P, K).

The limits of detection (LODs) required for the EU norms are shown in Table 3. The instrumental LODs, calculated from three blanks (3x standard deviation) are well below the required LODs, demonstrating the suitability of this instrumentation and analytical approach for the determination of trace elements in food according to the EN norms.

Food quality in relation to public safety is a primary concern that has led to the introduction of stringent legislation setting maximum levels of contaminants in foodstuffs. In particular, heavy metals are strictly regulated because their consumption in food is associated with a number of serious health conditions. ICP-MS is a multi-elemental technique, ideal for food safety analysis and the determination of heavy metals in foodstuffs, offering improved sensitivity, increased tolerance to matrix, high linear dynamic range, and high throughput. ■

Dr. Ducos is an ICP-MS application specialist, Dr. Hamester is an ICP-MS product manager, and Dr. Godula is a food safety specialist, all at Thermo Fisher Scientific. For more information, contact Dr. Ducos at [email protected] or +49 (0) 421 5493 227.

References

1. U.S. Food and Drug Administration. Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed. Available at: www.fda.gov/Food/ GuidanceComplianceRegulatoryInformation/GuidanceDocuments/ChemicalContaminantsandPesticides/ucm077969.htm. Accessed January 21, 2010.
2. U.S. Food and Drug Administration. Fact Sheet: Food Protection Plan. Available at: www.fda.gov/Food/FoodSafety/FoodSafetyPrograms/FoodProtectionPlan2007/ucm132705.htm. Accessed January 21, 2010.
3. European Commission. Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. Available at: eurlex.europa.eu/LexUriServ/site/en/oj/2006/l_364/l_36420061220en00050024.pdf. Accessed January 21, 2010.
4. European Commission. Commission Regulation (EC) No 629/2008 of 2 July 2008 amending Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs. Available at: www.fsai.ie/uploadedFiles/Commission_Regulation_EC_No_629_2008.pdf. Accessed January 21, 2010.
5. German Institute for Standardization. Foodstuffs – determination of trace elements – determination of tin by inductively coupled plasma mass spectrometry (ICP-MS) after pressure digestion; German version EN 15765:2009. DIN. Berlin; 2009.
6. German Institute for Standardization. Foodstuffs – determination of trace elements – determination of arsenic, cadmium, mercury, and lead in foodstuffs by inductively coupled plasma mass spectrometry (ICP-MS) after pressure digestion; German version EN 15763:2009. DIN. Berlin; 2009.
7. German Institute for Standardization. Foodstuffs – determination of trace elements – pressure digestion, DIN EN 13805:2002. DIN. Berlin; 2002.