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Contents Vol 11(4)

The persistence and transformation of silver nanoparticles in littoral lake mesocosms monitored using various analytical techniques

Lindsay M. Furtado A , Md Ehsanul Hoque A , Denise M. Mitrano B D , James F. Ranville B , Beth Cheever C E , Paul C. Frost C , Marguerite A. Xenopoulos C , Holger Hintelmann A and Chris D. Metcalfe A F
+ Author Affiliations
- Author Affiliations

A Trent University, Water Quality Center, 1600 Westbank Drive, Peterborough, ON, K9J 7B8, Canada.

B Colorado School of Mines, Department of Chemistry and Geochemistry, 1500 Illinois Street, Golden, CO 80401, USA.

C Trent University, Department of Biology, 1600 Westbank Drive, Peterborough, ON, K9J 7B8, Canada.

D Present address: Empa – Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, CH-9014 St Gallen, Switzerland.

E Present address: Michigan State University, Department of Microbiology and Molecular Genetics, 220 Trowbridge Road, East Lansing, MI 48824, USA.

F Corresponding author. Email: cmetcalfe@trentu.ca

Environmental Chemistry 11(4) 419-430 https://doi.org/10.1071/EN14064
Submitted: 31 March 2014  Accepted: 27 May 2014   Published: 25 August 2014

Environmental context. Silver nanoparticles discharged with municipal wastewater may contaminate surface waters and harm aquatic ecosystems. We applied several analytical techniques to investigate the persistence and transformation of silver nanoparticles in a natural lake environment, and show, through multiple lines of evidence, that they persisted in lake water for several weeks after addition. The nanoparticles were releasing silver ions through dissolution, but these toxic ions were likely binding with natural organic matter in the lake water.

Abstract. Silver nanoparticles (AgNPs) may be released into surface waters, where they can affect aquatic organisms. However, agglomeration, dissolution, surface modifications and chemical speciation are important processes that control the toxicity of AgNPs. The purpose of the study was to apply various methods for monitoring the persistence and transformation of AgNPs added to littoral lake mesocosms. Analysis of total Ag showed that the levels in the mesocosms declined rapidly in the first 12 h after addition, followed by a slower rate of dissipation with a half-life (t1/2) of ~20 days. Analysis using single particle ICP-MS (spICP-MS) showed no evidence of extensive homo-agglomeration of AgNPs. The stability of AgNPs was likely due to the low ionic strength and high concentrations of humic-rich dissolved organic carbon (DOC) in the lake water. Analyses by spICP-MS, cloud point extraction (CPE) and asymmetric flow field flow fractionation coupled to ICP-MS (AF4-ICP-MS) all indicated that the concentrations of AgNP decreased over time, and the nanoparticles underwent dissolution. However, the concentrations of dissolved silver, which includes Ag+, were generally below detection limits when analysed by centrifugal ultrafiltration and spICP-MS. It is likely that the majority of free ions released by dissolution were complexing with natural organic material, such as DOC. An association with DOC would be expected to reduce the toxicity of Ag+ in natural waters. Overall, we were able to characterise AgNP transformations in natural waters at toxicologically relevant concentrations through the use of multiple analytical techniques that compensate for the limitations of the individual methods.


References

[1]  J. K. Schluesener, H. J. Schluesener, Nanosilver: application and novel aspects of toxicology. Arch. Toxicol. 2013, 87, 569.
| Nanosilver: application and novel aspects of toxicology.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtlGmsrs%3D&md5=7d42b34cadba87367102aa842095806cCAS | 23344422PubMed |

[2]  B. Nowack, J. F. Ranville, S. Diamond, J. A. Gallego-Urrea, C. Metcalfe, J. Rose, N. Horne, A. A. Koelmans, S. J. Klaine, Potential scenarios for nanomaterial release and subsequent alteration in the environment. Environ. Toxicol. Chem. 2012, 31, 50.
| Potential scenarios for nanomaterial release and subsequent alteration in the environment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhs1yktr7M&md5=b3977061ab625444afef30ec0a3da937CAS | 22038832PubMed |

[3]  T. M. Benn, P. Westerhoff, Nanoparticle silver released into water from commercially available sock fabrics. Environ. Sci. Technol. 2008, 42, 4133.
| Nanoparticle silver released into water from commercially available sock fabrics.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXktlKjsL4%3D&md5=16dae2000740ddd05f5125241df26259CAS | 18589977PubMed |

[4]  F. Gottschalk, T. Sun, B. Nowack, Environmental concentrations of engineered nanomaterials: review of modeling and analytical studies. Environ. Pollut. 2013, 181, 287.
| Environmental concentrations of engineered nanomaterials: review of modeling and analytical studies.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtFSlsrfP&md5=7be267556cba6b63f2cffd78eb64df51CAS | 23856352PubMed |

[5]  H. J. Allen, C. A. Impellitteri, D. A. Macke, J. L. Heckman, H. C. Poynton, J. M. Lazorchak, S. Govindaswamy, D. L. Roose, M. N. Nadagouda, Effects from filtration, capping agents, and presence/absence of food on the toxicity of silver nanoparticles to Daphnia magna. Environ. Toxicol. Chem. 2010, 29, 2742.
| Effects from filtration, capping agents, and presence/absence of food on the toxicity of silver nanoparticles to Daphnia magna.Crossref | GoogleScholarGoogle Scholar | 20890913PubMed |

[6]  E. Farmen, H. N. Mikkelsen, O. Evensen, J. Einset, L. S. Heier, B. O. Rosseland, B. Salbu, K. E. Tollefsen, D. H. Oughton, Acute and sub-lethal effects in juvenile Atlantic salmon exposed to low μg L–1 concentrations of Ag nanoparticles. Aquat. Toxicol. 2012, 108, 78.
| Acute and sub-lethal effects in juvenile Atlantic salmon exposed to low μg L–1 concentrations of Ag nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtFWqtLg%3D&md5=21db895ac3f304ac7386d092baad8038CAS | 22265610PubMed |

[7]  P. Das, M. A. Xenopoulos, C. J. Williams, M. E. Hoque, C. D. Metcalfe, Effects of silver nanoparticles on bacterial activity in natural waters. Environ. Toxicol. Chem. 2012, 31, 122.
| Effects of silver nanoparticles on bacterial activity in natural waters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhs1yktr7F&md5=af6f62d2bed73936a33399541781ab2bCAS | 22012876PubMed |

[8]  E. Bae, H. Park, J. Lee, Y. Kim, J. Yoon, K. Park, K. Choi, J. Yi, Bacterial cytotoxicity of the silver nanoparticle related to physicochemical metrics and agglomeration properties. Environ. Toxicol. Chem. 2010, 29, 2154.
| Bacterial cytotoxicity of the silver nanoparticle related to physicochemical metrics and agglomeration properties.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXht12jsLjI&md5=8e6d41efd1be3561cfdaf1baaf4aa38eCAS | 20872676PubMed |

[9]  A. J. Kennedy, M. A. Chappell, A. J. Bednar, A. C. Ryan, J. G. Laird, J. K. Stanley, J. A. Steevens, Impact of organic carbon on the stability and toxicity of fresh and stored silver nanoparticles. Environ. Sci. Technol. 2012, 46, 10 772.
| Impact of organic carbon on the stability and toxicity of fresh and stored silver nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xht12ru7jF&md5=9f10630f2b1028032a8ac1652e972137CAS |

[10]  J. Gao, K. Powers, Y. Wang, H. Zhou, S. M. Roberts, B. M. Moudgil, B. Koopman, D. S. Barber, Influence of suwannee river humic acid on particle properties and toxicity of silver nanoparticles. Chemosphere 2012, 89, 96.
| Influence of suwannee river humic acid on particle properties and toxicity of silver nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XmvFKksLY%3D&md5=acdbdb9ab1400a15b7298a9c53e6eef0CAS | 22583785PubMed |

[11]  X. Li, J. J. Lenhari, H. W. Walker, Aggregation kinetics and dissolution of coated silver nanoparticles. Langmuir 2012, 28, 1095.
| Aggregation kinetics and dissolution of coated silver nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsF2lsLvL&md5=67c234af5c1b3e895d938921df686cd0CAS | 22149007PubMed |

[12]  K. M. Newton, H. L. Puppala, C. L. Kitchens, V. L. Colvin, S. J. Klaine, Silver nanoparticle toxicity to daphnia magna is a function of dissolved silver concentration. Environ. Toxicol. Chem. 2013, 32, 2356.
| Silver nanoparticle toxicity to daphnia magna is a function of dissolved silver concentration.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtlOku7nI&md5=1e2c8113550590e599fb20527651fd24CAS | 23761010PubMed |

[13]  X. Yang, A. P. Gondikas, S. M. Marinakos, M. Auffan, J. Liu, H. Hsu-Kim, J. N. Meyer, Mechanism of silver nanoparticle toxicity is dependent on dissolved silver and surface coating in Caenorhabditis elegans. Environ. Sci. Technol. 2012, 46, 1119.
| Mechanism of silver nanoparticle toxicity is dependent on dissolved silver and surface coating in Caenorhabditis elegans.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsFygt7vN&md5=29f8517bdb955eb83c1aeb28945039f7CAS | 22148238PubMed |

[14]  Z. Xiu, J. Ma, P. J. J. Alvarez, Differential effect of common ligands and molecular oxygen on antimicrobial activity of silver nanoparticles versus silver ions. Environ. Sci. Technol. 2011, 45, 9003.
| Differential effect of common ligands and molecular oxygen on antimicrobial activity of silver nanoparticles versus silver ions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXht1ags77I&md5=21bcd55abf75149ae1c6ade56f89ce2eCAS | 21950450PubMed |

[15]  A. P. Gondikas, A. Morris, B. C. Reinsch, S. M. Marinakos, G. V. Lowry, H. Hsu-Kim, Cysteine-induced modifications of zero-valent silver nanomaterials: implications for particle surface chemistry, aggregation, dissolution, and silver speciation. Environ. Sci. Technol. 2012, 46, 7037.
| Cysteine-induced modifications of zero-valent silver nanomaterials: implications for particle surface chemistry, aggregation, dissolution, and silver speciation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XksVKgu7Y%3D&md5=5152f219beee75322da049ba705c0411CAS | 22448900PubMed |

[16]  C. Levard, B. C. Reinsch, F. M. Michel, C. Oumahi, G. V. Lowry, G. E. Brown, Sulfidation processes of PVP-coated silver nanoparticles in aqueous solution: impact on dissolution rate. Environ. Sci. Technol. 2011, 45, 5260.
| Sulfidation processes of PVP-coated silver nanoparticles in aqueous solution: impact on dissolution rate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXmtlCkuro%3D&md5=78a71476ddabcc48bd33cb3b00909833CAS | 21598969PubMed |

[17]  D. He, M. W. Bligh, T. D. Waite, Effects of aggregate structure on the dissolution kinetics of citrate-stabilized silver nanoparticles. Environ. Sci. Technol. 2013, 47, 9148.
| Effects of aggregate structure on the dissolution kinetics of citrate-stabilized silver nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtFKlsLnN&md5=b6e1da30a77f87cf7d4939804f5f3cbaCAS | 23883329PubMed |

[18]  J. Liu, R. H. Hurt, Ion release kinetics and particle persistence in aqueous nano-silver colloids. Environ. Sci. Technol. 2010, 44, 2169.
| Ion release kinetics and particle persistence in aqueous nano-silver colloids.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXit1Wqsrc%3D&md5=eda8eefb62b5e038312ad7a39ce5d935CAS | 20175529PubMed |

[19]  S. Kittler, C. Greulich, J. Diendorf, M. Koeller, M. Epple, Toxicity of silver nanoparticles increases during storage because of slow dissolution under release of silver ions. Chem. Mater. 2010, 22, 4548.
| Toxicity of silver nanoparticles increases during storage because of slow dissolution under release of silver ions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXpsV2ltbo%3D&md5=22d2ff31e22b7d8515908241adbb5e5aCAS |

[20]  X. Li, J. J. Lenhart, Aggregation and dissolution of silver nanoparticles in natural surface water. Environ. Sci. Technol. 2012, 46, 5378.
| Aggregation and dissolution of silver nanoparticles in natural surface water.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XlsFemsLk%3D&md5=609388f4bb944bc4f5c354e4018e892fCAS | 22502776PubMed |

[21]  D. Cleveland, S. E. Long, P. L. Pennington, E. Cooper, M. H. Fulton, G. I. Scott, T. Brewer, J. Davis, E. J. Petersen, L. Wood, Pilot estuarine mesocosm study on the environmental fate of silver nanomaterials leached from consumer products. Sci. Total Environ. 2012, 421–422, 267.
| Pilot estuarine mesocosm study on the environmental fate of silver nanomaterials leached from consumer products.Crossref | GoogleScholarGoogle Scholar | 22369864PubMed |

[22]  J. M. Unrine, B. P. Colman, A. J. Bone, A. P. Gondikas, C. W. Matson, Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of ag nanoparticles. Part 1. Aggregation and dissolution. Environ. Sci. Technol. 2012, 46, 6915.
| Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of ag nanoparticles. Part 1. Aggregation and dissolution.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XksFWgtr8%3D&md5=4f84488d2001c1419559786ab72ffcb8CAS | 22452441PubMed |

[23]  G. V. Lowry, B. P. Espinasse, A. R. Badireddy, C. J. Richardson, B. C. Reinsch, L. D. Bryant, A. J. Bone, A. Deonarine, S. Chae, M. Therezien, B. P. Colman, H. Hsu-Kim, E. S. Bernhardt, C. W. Matson, M. R. Wiesner, Long-term transformation and fate of manufactured Ag nanoparticles in a simulated large scale freshwater emergent wetland. Environ. Sci. Technol. 2012, 46, 7027.
| Long-term transformation and fate of manufactured Ag nanoparticles in a simulated large scale freshwater emergent wetland.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XkvVyqtbk%3D&md5=0fc37e2708edc8dea008fa6870a70b80CAS | 22463850PubMed |

[24]  F. von der Kammer, P. L. Ferguson, P. A. Holden, A. Masion, K. R. Rogers, S. J. Klaine, A. A. Koelmans, N. Horne, J. M. Unrine, Analysis of engineered nanomaterials in complex matrices (environment and biota): general considerations and conceptual case studies. Environ. Toxicol. Chem. 2012, 31, 32.
| Analysis of engineered nanomaterials in complex matrices (environment and biota): general considerations and conceptual case studies.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhs1yksbfF&md5=2c389671872187661fdedaf142521bfcCAS | 22021021PubMed |

[25]  J. Liu, J. Chao, R. Liu, Z. Tan, Y. Yin, Y. Wu, G. Jiang, Cloud point extraction as an advantageous preconcentration approach for analysis of trace silver nanoparticles in environmental waters. Anal. Chem. 2009, 81, 6496.
| Cloud point extraction as an advantageous preconcentration approach for analysis of trace silver nanoparticles in environmental waters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXotFKmsr0%3D&md5=d1358259274587e92212587ad37e577eCAS |

[26]  M. E. Hoque, K. Khosravi, K. Newman, C. D. Metcalfe, Detection and characterization of silver nanoparticles in aqueous matrices using asymmetric-flow field flow fractionation with inductively coupled plasma mass spectrometry. J. Chromatogr. A 2012, 1233, 109.
| Detection and characterization of silver nanoparticles in aqueous matrices using asymmetric-flow field flow fractionation with inductively coupled plasma mass spectrometry.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xkt1Cnt7s%3D&md5=fa07936c3b8ac9c5b5433d5f2f798c4aCAS | 22381889PubMed |

[27]  A. R. Poda, A. J. Bednar, A. J. Kennedy, A. Harmon, M. Hull, D. M. Mitrano, J. F. Ranville, J. Steevens, Characterization of silver nanoparticles using flow-field flow fractionation interfaced to inductively coupled plasma mass spectrometry. J. Chromatogr. A 2011, 1218, 4219.
| Characterization of silver nanoparticles using flow-field flow fractionation interfaced to inductively coupled plasma mass spectrometry.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXnslKgurY%3D&md5=d6cd8a0b645494d4ee347a445a1557a5CAS | 21247580PubMed |

[28]  F. Laborda, J. Jimenez-Lamana, E. Bolea, J. R. Castillo, Selective identification, characterization and determination of dissolved silver(I) and silver nanoparticles based on single particle detection by inductively coupled plasma mass spectrometry. J. Anal. At. Spectrom. 2011, 26, 1362.
| Selective identification, characterization and determination of dissolved silver(I) and silver nanoparticles based on single particle detection by inductively coupled plasma mass spectrometry.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXnvVaqtro%3D&md5=573f705c12ca8eb90989c17d60dc11d3CAS |

[29]  H. E. Pace, N. J. Rogers, C. Jarolimek, V. A. Coleman, C. P. Higgins, J. F. Ranville, Determining transport efficiency for the purpose of counting and sizing nanoparticles via single particle inductively coupled plasma mass spectrometry. Anal. Chem. 2012, 84, 4633.
| Determining transport efficiency for the purpose of counting and sizing nanoparticles via single particle inductively coupled plasma mass spectrometry.Crossref | GoogleScholarGoogle Scholar |

[30]  D. M. Mitrano, E. K. Lesher, A. Bednar, J. Monserud, C. P. Higgins, J. F. Ranville, Detecting nanoparticulate silver using single-particle inductively coupled plasma-mass spectrometry. Environ. Toxicol. Chem. 2012, 31, 115.
| Detecting nanoparticulate silver using single-particle inductively coupled plasma-mass spectrometry.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhs1yktr7E&md5=9234fb3e71b09355b5b281b35d380b3dCAS | 22012920PubMed |

[31]  Tech note: zeta/ pH curves and isoelectric point data for standard nanoComposix silver citrate and PVP nanoparticle dispersions, v.1.0 2012 (nanoComposix: San Diego, CA). Available at http://cdn.shopify.com/s/files/1/0257/8237/files/Tech_Note_-_Zeta_and_pH_Curves_for_nanoComposix_Citrate_and_PVP_Capped_Silver_Nanoparticles.pdf [Verified 24 July 2014].

[32]  D. M. Mitrano, A. Barber, A. Bednar, P. Westerhoff, C. P. Higgins, J. F. Ranville, Silver nanoparticle characterization using single particle ICP-MS (SP-ICP-MS) and asymmetrical flow field flow fractionation ICP-MS (AF4-ICP-MS). J. Anal. At. Spectrom. 2012, 27, 1131.
| Silver nanoparticle characterization using single particle ICP-MS (SP-ICP-MS) and asymmetrical flow field flow fractionation ICP-MS (AF4-ICP-MS).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XosFSks7c%3D&md5=53dd85295d35e6494c621abc69bd3e31CAS |

[33]  E. Bolea, F. Laborda, J. R. Castillo, Metal associations to microparticles, nanocolloids and macromolecules in compost leachates: size characterization by asymmetrical flow field-flow fractionation coupled to ICP-MS. Anal. Chim. Acta 2010, 661, 206.
| Metal associations to microparticles, nanocolloids and macromolecules in compost leachates: size characterization by asymmetrical flow field-flow fractionation coupled to ICP-MS.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtlOmtrs%3D&md5=258fd9d949f9a49e5f81fa94b1f1b094CAS | 20113737PubMed |

[34]  M. Delay, T. Dolt, A. Woellhaf, R. Sembritzki, F. H. Frimmel, Interactions and stability of silver nanoparticles in the aqueous phase: influence of natural organic matter (NOM) and ionic strength. J. Chromatogr. A 2011, 1218, 4206.
| Interactions and stability of silver nanoparticles in the aqueous phase: influence of natural organic matter (NOM) and ionic strength.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXnslKgurg%3D&md5=75dec1e6a53d4c048e021e3e3e3b5d6dCAS | 21435646PubMed |

[35]  J. Dobias, R. Bernier-Latmani, Silver release from silver nanoparticles in natural waters. Environ. Sci. Technol. 2013, 47, 4140.
| Silver release from silver nanoparticles in natural waters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXktleksbo%3D&md5=5f4ab9c5241bfb9ce061f3af64f5aa95CAS | 23517230PubMed |

[36]  D. M. Mitrano, J. F. Ranville, A. Bednar, K. Kazor, A. S. Hering, C. P. Higgins, Tracking dissolution of silver nanoparticles at environmentally relevant concentrations in laboratory, natural and processed water using single particle ICP-MS (spICP-MS). Environ. Sci. Nano. 2014, 1, 248.
| Tracking dissolution of silver nanoparticles at environmentally relevant concentrations in laboratory, natural and processed water using single particle ICP-MS (spICP-MS).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXotFyqtb4%3D&md5=35dfe6fbd6a9f98edb4f85ce74277a94CAS |

[37]  C. Levard, E. M. Hotze, G. V. Lowry, G. E. Brown, Environmental transformations of silver nanoparticles: impact on stability and toxicity. Environ. Sci. Technol. 2012, 46, 6900.
| Environmental transformations of silver nanoparticles: impact on stability and toxicity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XitlGjt7o%3D&md5=4dae6e02caa0d9ab4a861e91882a1b9dCAS | 22339502PubMed |

[38]  A. J. Bone, B. P. Colman, A. P. Gondikas, K. M. Newton, K. H. Harrold, R. M. Cory, J. M. Unrine, S. J. Klaine, C. W. Matson, R. T. Di Giulio, Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles. Part 2. Toxicity and Ag speciation. Environ. Sci. Technol. 2012, 46, 6925.
| Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles. Part 2. Toxicity and Ag speciation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XnvV2ntrc%3D&md5=f5292e081ff21b06a06e063ac075e162CAS | 22680837PubMed |

[39]  Z. Wu, W. Tseng, Combined cloud point extraction and tween 20-stabilized gold nanoparticles for colorimetric assay of silver nanoparticles in environmental water. Anal. Methods. 2011, 3, 2915.
| Combined cloud point extraction and tween 20-stabilized gold nanoparticles for colorimetric assay of silver nanoparticles in environmental water.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsFKlsrbJ&md5=a43bc37839aa8b06f9df479b0534ed49CAS |

[40]  R. Ma, C. Levard, S. M. Marinakos, Y. Cheng, J. Liu, F. M. Michel, G. E. Brown, G. V. Lowry, Size-controlled dissolution of organic-coated silver nanoparticles. Environ. Sci. Technol. 2012, 46, 752.
| Size-controlled dissolution of organic-coated silver nanoparticles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsFGqsrnF&md5=5af3c81d2b7d3a31dca335e610d1083bCAS | 22142034PubMed |

[41]  G. Hartmann, T. Baumgartner, M. Schuster, Influence of particle coating and matrix constituents on the cloud point extraction efficiency of silver nanoparticles (Ag-NPs) and application for monitoring the formation of Ag-NPs from Ag+. Anal. Chem. 2014, 86, 790.
| Influence of particle coating and matrix constituents on the cloud point extraction efficiency of silver nanoparticles (Ag-NPs) and application for monitoring the formation of Ag-NPs from Ag+.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhvVGktLbN&md5=6d013d7739a44630077a3e6a53f90e27CAS | 24274840PubMed |

[42]  L. Telgmann, C. D. Metcalfe, H. Hintelmann, Rapid size characterization of silver nanoparticles by single particle ICP-MS and isotope dilution. J. Anal. At. Spectrom. 2014, 29, 1265.
| Rapid size characterization of silver nanoparticles by single particle ICP-MS and isotope dilution.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhtVajtLnK&md5=86c42192148a1a3b5dde083c82a26131CAS |

[43]  G. V. Lowry, K. B. Gregory, S. C. Apte, J. R. Lead, Transformations of nanomaterials in the environment. Environ. Sci. Technol. 2012, 46, 6893.
| Transformations of nanomaterials in the environment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XmvFajtbs%3D&md5=ffe75c0f5fd3c0eb997ff49828357fb0CAS | 22582927PubMed |

[44]  A. J. Bednar, A. R. Poda, D. M. Mitrano, A. J. Kennedy, E. P. Gray, J. F. Ranville, C. A. Hayes, F. H. Crocker, J. A. Steevens, Comparison of on-line detectors for field flow fractionation analysis of nanomaterials. Talanta 2013, 104, 140.
| Comparison of on-line detectors for field flow fractionation analysis of nanomaterials.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXmt1SmsLc%3D&md5=dc4807560df15dd3bcfd1da7372c7a6fCAS | 23597901PubMed |

[45]  S. Dubascoux, I. Le Hecho, M. P. Gautier, G. Lespes, On-line and off-line quantification of trace elements associated to colloids by as-fl-FFF and ICP-MS. Talanta 2008, 77, 60.
| On-line and off-line quantification of trace elements associated to colloids by as-fl-FFF and ICP-MS.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtFCit7nP&md5=5d4f2b647f990486bd5378bbb75ae950CAS | 18804599PubMed |

[46]  C. Babiarz, J. Hurley, D. Krabbenhoft, C. Gilmour, B. Branfireun, Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff. Sci. Total Environ. 2003, 304, 295.
| Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXit12itrY%3D&md5=0e12983db1cfc1bb4978aaba2e463bddCAS | 12663191PubMed |

[47]  H. Hagendorfer, R. Kaegi, M. Parlinska, B. Sinnet, C. Ludwig, A. Ulrich, Characterization of silver nanoparticle products using asymmetric flow field flow fractionation with a multidetector approach – a comparison to transmission electron microscopy and batch dynamic light scattering. Anal. Chem. 2012, 84, 2678.
| Characterization of silver nanoparticle products using asymmetric flow field flow fractionation with a multidetector approach – a comparison to transmission electron microscopy and batch dynamic light scattering.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xhs1Ontbw%3D&md5=bb69f2f365ee0eac8fd85f5f0e72a83fCAS | 22304567PubMed |