To understand the fate and exposure of engineered nanoparticles (ENPs) to environmental media, it is important to identify ENPs in the natural occurring nanoparticles (NNPs). Although nanomaterials have unique physical properties such as uniform particle size, hierarchical nanostructure, well-defined crystalline structure, and high surface area, compared to bulk materials, these properties are not suitable references to differentiate between ENPs and NNPs. Therefore, the identification and quantification of ENPs pose a big challenge to analysis. Herein, we did a feasibility study to distinguish between ENPs and NNPs based on the elemental ratio of target elements (Ti and Zn) to background elements (Fe and Al). Morphologies, particle size, and elemental analysis for 12 NNPs, 4 ENPs, and 3 NPs contained in consumer products were conducted. NPs were extracted from raw materials via density gradient ultracentrifugation and alkaline digestion. In a logarithm plot for the elemental ratio of {Ti+Zn} to {Ti/Zn}/{Fe+Al} and ternary plot of {Ti+Zn}, Fe, and Al ions for all samples, ENPs have a distinct contrast with NNPs. Therefore, it is expected that the suggested analysis for elemental ratio could be a preliminary screening tool to differentiate between ENPs and NNPs.

Engineered Nanoparticles Natural Nanoparticles Nano-consumer Products Density Gradient Ultracentrifugation Alkaline Digestion

Montano MD, Lowry GV, von der Kammer F, Blue J, Ranville JF, Environ. Chem., 11, 351 (2014)
Nowack B, Bucheli TD, Environ. Pollut., 150, 50 (2007)
Hong JS, Kim S, Lee SH, Jo E, Lee B, Yoon J, Eom IC, Kim HM, Kim P, Choi K, Lee MY, Seo YR, Kim Y, Lee Y, Choi J, Park K, Nanotoxicology, 8, 349 (2014)
Bae E, Lee BC, Kim Y, Choi K, Yi J, Korean J. Chem. Eng., 30(2), 364 (2013)
Bernhardt ES, Colman BP, Hochella MF, Cardinale BJ, Nisbet RM, Richardson CJ, Yin L, J. Environ. Qual., 39, 1 (2010)
Park EJ, Kim H, Kim Y, Yi J, Choi K, Park K, Toxicol., 275, 65 (2010)
Sharma VK, Filip J, Zboril R, Varma RS, Chem. Soc. Rev., 44, 8410 (2015)
Znaker H, Schierz A, Annu. Rev. Anal. Chem., 5, 107 (2012)
Gulson B, Wong H, Environ. Health Perspect., 114, 1486 (2006)
Lowry GV, Gregory KB, Apte SC, Lead JR, Environ. Sci. Technol., 46, 6893 (2012)
Abd El-Rahman M, El-Khadragy MF, Abd-El Hay H, Gab-Allah DM, J. Hazard. Mater., 186(2-3), 1527 (2011)
Sim JH, Umh HN, Shin HH, Sung HK, Oh SY, Lee BC, Selvaraj R, Kim Y, J. Ind. Eng. Chem., 20(5), 3157 (2014)
Park S, Kim Y, J. Ind. Eng. Chem., 41, 62 (2016)
Kwak JY, Choi JB, J. Miner. Soc. Korea, 27, 197 (2014)
Chen DH, Caruso RA, Adv. Funct. Mater., 23(11), 1356 (2013)
Park S, Selvaraj R, Meetani MA, Kim Y, J. Ind. Eng. Chem., 45, 206 (2017)
Trouiller B, Reliene R, Westbrook A, Solaimani P, Schiestl RH, Cancer Res., 69, 8784 (2009)
Lee J, Kim J, Shin Y, Ryu J, Eom IC, Lee JS, Kim Y, Kim P, Choi KH, Lee BC, Ecotox. Environ. Safe., 104, 9 (2014)
Song U, Shin M, Lee G, Roh J, Kim Y, Lee EJ, Biol. Trace Elem. Res., 155, 93 (2013)
Arnold MS, Green AA, Hulvat JF, Stupp SI, Hersam MC, Nat. Nanotechnol., 1(1), 60 (2006)
Lu YC, Wang LL, Wang DJ, Xie TF, Chen LP, Lin YH, Mater. Chem. Phys., 129(1-2), 281 (2011)
Park S, Park J, Selvarjay R, Kim Y, J. Ind. Eng. Chem., 31, 269 (2015)
Pal M, Serrano JG, Santiago P, Pal U, J. Phys. Chem., 111, 96 (2007)
Gondikas AP, von der Kammer F, Reed RB, Wagner S, Ranville JF, Hofmann T, Environ. Sci. Technol., 48, 5415 (2014)
Bartov G, Deonarine A, Johnson TM, Ruhl L, Vengosh A, Hsu-Kim H, Environ. Sci. Technol., 47, 2092 (2013)
Klaines SJ, Koelmans AA, Horne N, Carley S, Handy RD, Kapustka L, Nowack B, von der Kammer F, Environ. Toxicol. Chem., 31, 3 (2012)