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Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry.
Environ Sci Process Impacts. 2014 Nov; 16(11):2536-44.ES

Abstract

The wide use of metal-based nanomaterials such as zinc oxide (ZnO) nanoparticles (NPs) has generated concerns regarding their environmental and health risks. For ZnO NPs, their toxicity in aquatic systems often depends on the release of dissolved zinc species, and the rate of dissolution is influenced by water chemistry, including the presence of zinc-chelating ligands. A challenge, however, remains in quantifying the dissolution of ZnO NPs, particularly for time scales that are short enough to determine rates. This paper reports the application of anodic stripping voltammetry (ASV) with a hanging mercury drop electrode to directly measure the concentration of dissolved zinc in ZnO NP suspensions, without separation of the ZnO NPs from the aqueous phase. The effects of the deposition time and the electrochemical potential scan rate on the ASV measurement were consistent with expectations for dissolved phase measurements. The dissolved zinc concentration measured by ASV ([Zn]ASV) was compared with that measured by inductively coupled plasma mass spectrometry (ICP-MS) after ultracentrifugation ([Zn]ICP-MS), for four types of ZnO NPs with different coatings and primary particle diameters. For small ZnO NPs (4-5 nm), [Zn]ASV was 20% higher than [Zn]ICP-MS, suggesting that these small NPs contributed to the voltammetric measurement. For larger ZnO NPs (approximately 20 nm), [Zn]ASV was (79 ± 19)% of [Zn]ICP-MS, despite the high concentrations of ZnO NPs in suspension. Using ASV, the dissolution of ZnO NPs was studied, with or without Suwannee River Fulvic Acid (SRFA). Although SRFA diminished the ASV stripping current, dissolution of 20 nm ZnO NPs was significantly promoted at high fulvic acid to ZnO NP ratios. The ASV method described in this paper provides a useful tool for studying the dissolution kinetics of ZnO NPs in complex environmental matrices.

Authors+Show Affiliations

Department of Civil and Environmental Engineering, Duke University, Box 90287, NC 27708, USA. hsukim@duke.edu.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

25220562

Citation

Jiang, Chuanjia, and Heileen Hsu-Kim. "Direct in Situ Measurement of Dissolved Zinc in the Presence of Zinc Oxide Nanoparticles Using Anodic Stripping Voltammetry." Environmental Science. Processes & Impacts, vol. 16, no. 11, 2014, pp. 2536-44.
Jiang C, Hsu-Kim H. Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry. Environ Sci Process Impacts. 2014;16(11):2536-44.
Jiang, C., & Hsu-Kim, H. (2014). Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry. Environmental Science. Processes & Impacts, 16(11), 2536-44. https://doi.org/10.1039/c4em00278d
Jiang C, Hsu-Kim H. Direct in Situ Measurement of Dissolved Zinc in the Presence of Zinc Oxide Nanoparticles Using Anodic Stripping Voltammetry. Environ Sci Process Impacts. 2014;16(11):2536-44. PubMed PMID: 25220562.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry. AU - Jiang,Chuanjia, AU - Hsu-Kim,Heileen, PY - 2014/9/16/entrez PY - 2014/9/16/pubmed PY - 2015/5/12/medline SP - 2536 EP - 44 JF - Environmental science. Processes & impacts JO - Environ Sci Process Impacts VL - 16 IS - 11 N2 - The wide use of metal-based nanomaterials such as zinc oxide (ZnO) nanoparticles (NPs) has generated concerns regarding their environmental and health risks. For ZnO NPs, their toxicity in aquatic systems often depends on the release of dissolved zinc species, and the rate of dissolution is influenced by water chemistry, including the presence of zinc-chelating ligands. A challenge, however, remains in quantifying the dissolution of ZnO NPs, particularly for time scales that are short enough to determine rates. This paper reports the application of anodic stripping voltammetry (ASV) with a hanging mercury drop electrode to directly measure the concentration of dissolved zinc in ZnO NP suspensions, without separation of the ZnO NPs from the aqueous phase. The effects of the deposition time and the electrochemical potential scan rate on the ASV measurement were consistent with expectations for dissolved phase measurements. The dissolved zinc concentration measured by ASV ([Zn]ASV) was compared with that measured by inductively coupled plasma mass spectrometry (ICP-MS) after ultracentrifugation ([Zn]ICP-MS), for four types of ZnO NPs with different coatings and primary particle diameters. For small ZnO NPs (4-5 nm), [Zn]ASV was 20% higher than [Zn]ICP-MS, suggesting that these small NPs contributed to the voltammetric measurement. For larger ZnO NPs (approximately 20 nm), [Zn]ASV was (79 ± 19)% of [Zn]ICP-MS, despite the high concentrations of ZnO NPs in suspension. Using ASV, the dissolution of ZnO NPs was studied, with or without Suwannee River Fulvic Acid (SRFA). Although SRFA diminished the ASV stripping current, dissolution of 20 nm ZnO NPs was significantly promoted at high fulvic acid to ZnO NP ratios. The ASV method described in this paper provides a useful tool for studying the dissolution kinetics of ZnO NPs in complex environmental matrices. SN - 2050-7895 UR - https://www.unboundmedicine.com/medline/citation/25220562/Direct_in_situ_measurement_of_dissolved_zinc_in_the_presence_of_zinc_oxide_nanoparticles_using_anodic_stripping_voltammetry_ L2 - https://doi.org/10.1039/c4em00278d DB - PRIME DP - Unbound Medicine ER -