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Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes.

ABSTRACT: Residual metal impurities in carbon nanotubes (CNTs) provide a means to distinguish CNT from non-CNT sources of elemental carbon in environmental samples. A practical and cost-effective analytical approach is needed to support routine surface monitoring of CNT metal tracers using wipe sampling. Wipe sampling for CNT metal tracers is considered a qualitative indicator of the presence of CNTs, not a quantitative exposure metric. In this study, two digestion approaches (microwave-assisted nitric acid/H2O2 digestion and ultrasonic nitric/HF acid digestion) in conjunction with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) determination were evaluated for their ability to extract metal impurities from CNT particles captured on wipe substrates. Aliquots of different carbon nanotubes (including NIST 2483 single-wall CNT) with and without GhostWipes™ (ASTM E-1792 compliant) were used to compare the performance of the digestion methods. The microwave digestion method accommodated the bulky wipe sample and also eliminated potential ICP-MS signal interferences related to incomplete digestion. Although quantitative recoveries requiring lengthy multistep digestion protocols may be necessary in other applications, the near-total recoveries achieved in the present study for CNT catalyst elements were adequate for identifying surface contamination of CNTs in the workplace using wipe sampling.

SUBMITTER: Avramescu ML

PROVIDER: S-EPMC5128706 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes.

Avramescu Mary-Luyza ML Rasmussen Pat E PE Chénier Marc M

Journal of analytical methods in chemistry 20161116

Residual metal impurities in carbon nanotubes (CNTs) provide a means to distinguish CNT from non-CNT sources of elemental carbon in environmental samples. A practical and cost-effective analytical approach is needed to support routine surface monitoring of CNT metal tracers using wipe sampling. Wipe sampling for CNT metal tracers is considered a qualitative indicator of the presence of CNTs, not a quantitative exposure metric. In this study, two digestion approaches (microwave-assisted nitric ac ...[more]

PMID: 27974992

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Project description:In this research, the synergistic antiviral effects of carbon nanotubes (CNTs) and metal oxides (MO) in the form of novel hybrid structures (MO-CNTs) are presented. Raw CNTs, Ni(OH)2, Fe2O3 and MnO2, as well as Ni(OH)2-CNT, Fe2O3-CNT and MnO2-CNT were explored in this study against Escherichia. coli MS2 bacteriophage, which was used as a virus surrogate. The nano particles were synthesized and characterized using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), particle size analysis, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Kinetic parameters such as the LD50 (lethal dose to kill 50% of the population), T50 and T80 (time taken to kill 50% and 80% of the population), SGR (specific growth rate) and IRD (initial rate of deactivation of the population) were also studied to examine the antiviral efficacy of these nanomaterials. Among all the nanomaterials, Ni(OH)2-CNT was the most effective antiviral agent followed by Fe2O3-CNT, MnO2-CNT, raw CNTs, Ni(OH)2, Fe2O3 and MnO2. When comparing the metal oxide-CNTs to the raw CNTs, the average enhancement was 20.2%. The average antiviral activity enhancement of the MO-CNTs were between 50 and 54% higher than the MO itself. When compared to the raw CNTs, the average enhancement over all the MO-CNTs was 20.2%. The kinetic studies showed that the LD50 of Ni(OH)2-CNT was the lowest (16µg/mL), which implies that it was the most toxic of all the compounds studied. The LD50 of Ni(OH)2, Fe2O3 and MnO2 were 17.3×, 14.5× and 10.8× times greater than their corresponding hybrids with the CNTs. The synergistic mechanism involved the entrapment of phage viruses by the nano structured CNTs leading to structural damage along with toxicity to phage from the release of MO ions. The metal oxide-CNT nano hybrids developed in this project are promising candidates in applications such as antiviral coatings, nanocomposites, adsorbents and as components of personal protection gears.

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Dataset Information

Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes.

Publications

Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes.

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