The Current World of Nanomaterial Characterization: Discussion of Analytical Instruments for Nanomaterial Characterization

Salamon, Andrew W.

doi:10.1089/ees.2012.0330

Cited by 18 publications

(10 citation statements)

References 5 publications

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“…Elemental analysis was used to determine the absolute amounts of C, H, N, and S elements of the synthesized EGOs [33], and to calculate their carbon/oxygen (C/O) atomic ratio, which is indicative of the degree of oxidation. Therefore, this shows the effectiveness of the electrochemical oxidation process of graphite.…”

Section: Oxidation Level Of the Synthesized Egosmentioning

confidence: 99%

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

et al. 2020

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Graphene oxide (GO) is an attractive alternative to graphene for many applications due to its captivating optical, chemical, and electrical characteristics. In this work, GO powders with a different amount of surface groups were synthesized from graphite via an electrochemical two-stage process. Many synthesis conditions were tried to maximize the oxidation level, and comprehensive characterization of the resulting samples was carried out via elemental analysis, microscopies (TEM, SEM, AFM), X-ray diffraction, FT-IR and Raman spectroscopies as well as electrical resistance measurements. SEM and TEM images corroborate that the electrochemical process used herein preserves the integrity of the graphene flakes, enabling to obtain large, uniform and well exfoliated GO sheets. The GOs display a wide range of C/O ratios, determined by the voltage and time of each stage as well as the electrolyte concentration, and an unprecedented minimum C/O value was obtained for the optimal conditions. FT-IR evidences strong intermolecular interactions between neighbouring oxygenated groups. The intensity ratio of D/G bands in the Raman spectra is high for samples prepared using concentrated H2SO4 as an electrolyte, indicative of many defects. Furthermore, these GOs exhibit smaller interlayer spacing than that expected according to their oxygen content, which suggests predominant oxidation on the flake edges. Results point out that the electrical resistance is conditioned mostly by the interlayer distance and not simply by the C/O ratio. The tuning of the oxidation level is useful for the design of GOs with tailorable structural, electrical, optical, mechanical, and thermal properties.

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Section: Oxidation Level Of the Synthesized Egosmentioning

confidence: 99%

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

et al. 2020

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“…It is therefore not surprising that there are a large number of conflicting reports and knowledge gaps in the nanotoxicity literature concerning MWNTs (for reviews, see [ 20 , 35 , 36 , 37 , 38 , 39 , 40 ]). Toward gaining a more thorough understanding of the structure-activity relationships of MWNTs, one mantra that has gained acceptance in the nanotoxicity community is that thorough MWNT characterizations should accompany toxicity investigations, especially since no one analytical technique can probe all aspects of MWNT physicochemical properties that may correlate with a biological response [ 25 , 29 , 31 , 32 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

The Importance of Evaluating the Lot-to-Lot Batch Consistency of Commercial Multi-Walled Carbon Nanotube Products

et al. 2020

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The biological response of multi-walled carbon nanotubes (MWNTs) is related to their physicochemical properties and a thorough MWNT characterization should accompany an assessment of their biological activity, including their potential toxicity. Beyond characterizing the physicochemical properties of MWNTs from different sources or manufacturers, it is also important to characterize different production lots of the same MWNT product from the same vendor (i.e., lot-to-lot batch consistency). Herein, we present a comprehensive physicochemical characterization of two lots of commercial pristine MWNTs (pMWNTs) and carboxylated MWNTs (cMWNTs) used to study the response of mammalian macrophages to MWNTs. There were many similarities between the physicochemical properties of the two lots of cMWNTs and neither significantly diminished the 24-h proliferation of RAW 264.7 macrophages up to the highest concentration tested (200 μg cMWNTs/mL). Conversely, several physicochemical properties of the two lots of pMWNTs were different; notably, the newer lot of pMWNTs displayed less oxidative stability, a higher defect density, and a smaller amount of surface oxygen species relative to the original lot. Furthermore, a 72-h half maximal inhibitory concentration (IC-50) of ~90 µg pMWNTs/mL was determined for RAW 264.7 cells with the new lot of pMWNTs. These results demonstrate that subtle physicochemical differences can lead to significantly dissimilar cellular responses, and that production-lot consistency must be considered when assessing the toxicity of MWNTs.

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“…Since a thorough characterization of SWCNT soot is imperative for exacting assessments of product quality and environmental health and safety (EH&S) risk [6,9,33–38], the primary goal of this work was to develop a routine laboratory procedure for an extensive elemental analysis of SWCNT soot using readily-available bulk methods of analysis. The ancillary goals were to keep costs to a minimum to facilitate monitoring of batch-to-batch variability, which is often overlooked by end users [6], and to minimize sample size requirements to <100 mg, in cases where the amount of sample was limited.…”

Section: Introductionmentioning

confidence: 99%

The importance of an extensive elemental analysis of single-walled carbon nanotube soot

Braun

Pantano

2014

Carbon

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Few manufacturers provide elemental analysis information on the certificates of analysis of their single-walled carbon nanotube (SWCNT) soot products, and those who do primarily perform surface sensitive analyses that may not accurately represent the bulk properties of heterogeneous soot samples. Since the accurate elemental analysis of SWCNT soot is a requisite for exacting assessments of product quality and environmental health and safety (EH&S) risk, the purpose of this work was to develop a routine laboratory procedure for an extensive elemental analysis of SWCNT soot using bulk methods of analyses. Herein, a combination of carbon, hydrogen, nitrogen, sulfur, and oxygen (CHNS/O) combustion analyses, oxygen flask combustion/anion chromatography (OFC/AC), graphite furnace-atomic absorption spectroscopy (GF-AAS), and inductively coupled plasma-mass spectroscopy (ICP-MS) were used to generate a 77-element analysis of two as-received CoMoCAT® SWCNT soot products. Fourteen elements were detected in one product, nineteen in the other, and each data set was compared to its respective certificate of analysis. The addition of the OFC/AC results improved the accuracy of elements detected by GF-AAS and ICP-MS, and an assessment was performed on the results that concluded that the trace elemental impurities should not pose an EH&S concern if these soot products became airborne.

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The Current World of Nanomaterial Characterization: Discussion of Analytical Instruments for Nanomaterial Characterization

Cited by 18 publications

References 5 publications

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

Tailorable Synthesis of Highly Oxidized Graphene Oxides via an Environmentally-Friendly Electrochemical Process

The Importance of Evaluating the Lot-to-Lot Batch Consistency of Commercial Multi-Walled Carbon Nanotube Products

The importance of an extensive elemental analysis of single-walled carbon nanotube soot

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