Feasibility of the development of reference materials for the detection of Ag nanoparticles in food: neat dispersions and spiked chicken meat
The feasibility of producing colloidal silver nanoparticle reference materials and silver nanoparticle spiked reference matrix materials was investigated. Two concentrations of PVP-coated silver nanoparticle dispersions were evaluated and used to spike chicken meat, with the aim of producing a set of reference materials to support the development of analytical methods for the detection and quantification of nanoparticles in food. Aqueous silver nanoparticle (AgNP) dispersions were evaluated for their homogeneity of mass fraction and particle size and found sufficiently homogeneous to be used as reference materials. Stability studies at 4 °C, 18 °C and 60 °C demonstrated sufficient short- and long-term stability, although particle size decreases in a linear fashion at 60 °C. The AgNP dispersions were characterized for total Ag mass fraction by ICP-OES, dissolved Ag content by ultrafiltration-ICP-MS, as well as AgNP particle size by dynamic light scattering, transmission electron microscopy (TEM) and gas-phase electrophoretic molecular mobility analysis. Chicken breasts were homogenized by cryo-milling and spiked with aqueous AgNP dispersions. Rapid freezing over liquid nitrogen resulted in homogeneous and stable materials. The spiked chicken materials were characterized for their total Ag mass fraction by neutron activation analysis and for the AgNP particle size by TEM and single-particle inductively coupled plasma mass spectrometry. The observed differences in particle sizes between the spiked chicken samples and the original silver dispersions indicate relevant matrix effects. The materials demonstrate that production and characterization of reference materials for the detection and quantification of silver nanoparticles in meat are feasible, but challenges especially in assessing stability and having sufficiently precise methods for assessment of homogeneity and stability remain.
KeywordsEngineered nanoparticles Food Reference material Matrix reference materials Silver nanoparticles
The work leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no 245162. The authors thank Mrs. Meeus (EC JRC-IRMM) for conducting the microbiology tests.
- 1.EC Regulation 1169/2011 on the provision of food information to consumersGoogle Scholar
- 5.ISO Guide 34, General requirements for the competence of reference materials producers, International Organization for Standardization, Geneva, Switzerland, 2009Google Scholar
- 8.Loeschner K, Navratilova J, Købler C, Mølhave K, Wagner S, von der Kammer F, Larsen EH (2013) Detection and characterization of silver nanoparticles in chicken meat by asymmetric flow field flow fractionation with detection by conventional or single particle ICP-MS. Anal Bioanal Chem 405:8185–8195CrossRefGoogle Scholar
- 10.Menzel M, Bienert R, Bremser W, Girod M, Rolf S, Thünemann AF, Emmerling F (2013) Certification Report Certified Reference Material BAM-N001 Particle Size Parameters of Nano Silver, BAM Federal Institute for Materials Research and Testing, http://www.rm-certificates.bam.de/de/rm-certificates_media/rm_cert_particle_size/bam_n001repe.pdf
- 14.Grombe R, Allmaier G, Charoud-Got J, Dudkiewicz A, Emteborg H, Hofmann T, Lehner A, Llinas M, Seghers J, Solans C, von der Kammer F, Wagner S, Linsinger TPJ (2014) Production of reference materials for the detection and size determination of silica nanoparticles in tomato soup. Anal Bioanal Chem 406: 3895–3907. doi: 10.1007/s00216-013-7554-1 Google Scholar
- 15.Dudkiewicz A, Boxall ABA, Chaudhry Q, Mølhave K, Tiede K, Hofmann P, Linsinger TPJ (2014) Uncertainties of size measurements in electron microscopy characterization of nanomaterials in foods. Food Chem. doi: 10.1016/j.foodchem.2014.12.071 (in press)
- 22.ISO Guide 35, Reference materials—General and statistical principles for certification, International Organization for Standardization, Geneva, Switzerland, 2006Google Scholar