Raman Spectroscopy for the Analysis of Microplastics in Aquatic Systems

2021 ◽  
pp. 000370282110431
Author(s):  
Veronica Nava ◽  
Maria Luce Frezzotti ◽  
Barbara Leoni
Keyword(s):  
Raman Spectroscopy ◽  
High Spatial Resolution ◽  
Deep Understanding ◽  
R Package ◽  
Aquatic Systems ◽  
Raman Analysis ◽  
Procedural Information ◽  
Chemical Fingerprints ◽  
The Status ◽  
Actual Material

Raman spectroscopy is gaining ground in the analysis of microplastics, especially due to its high spatial resolution that allows the investigation of small plastic particles, whose numeric abundance is argued to be particularly relevant in aquatic systems. Here, we aimed at outlining the status of Raman analysis of microplastics from aquatic systems, highlighting the advantages and the drawbacks of this technique and critically presenting tools and ways to effectively employ this instrument and to improve the spectra obtained and their interpretation. In particular, we summarized procedural information for the use of Raman spectroscopy, and we discussed issues linked to fluorescence interference and the analysis of weathered polymers, which may complicate the interpretation of Raman signatures. In this context, a deep understanding of the different plastic polymers and their Raman peaks and chemical fingerprints is fundamental to avoid misidentification. Therefore, we provided a catalog with detailed information about peaks of most common plastic polymers, and this represents, to the best of our knowledge, the first comprehensive resource that systematically synthesized plastic Raman peaks. Additionally, we focused on plastic additives, which are contained in the majority of plastics. These compounds are often intense in Raman scattering and may partly or completely overlie the actual material types, resulting in the identification of additives alone or misidentification issue. For these reasons, we also presented a new R package “RamanMP” that includes a database of 356 spectra (325 of which are additives). This will help to foster the use of this technique, which is becoming especially relevant in microplastic analysis.

scholarly journals Fabrication of highly uniform nanoprobe via the automated process for tip-enhanced Raman spectroscopy

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2989-2996
Author(s):  
Dong Hyeon Kim ◽  
Chanwoo Lee ◽  
Byeong Geun Jeong ◽  
Sung Hyuk Kim ◽  
Mun Seok Jeong
Keyword(s):  
Raman Spectroscopy ◽  
Human Error ◽  
Acidic Solution ◽  
High Spatial Resolution ◽  
Electrochemical Etching ◽  
Radius Of Curvature ◽  
Enhanced Raman Scattering ◽  
Tip Enhanced Raman Spectroscopy ◽  
Highly Uniform ◽  
Etching System

AbstractIn a tip-enhanced Raman spectroscopy (TERS) system, using a sharp nanotip that comprises a noble metal is critical to attaining high spatial resolution and highly enhanced Raman scattering. A strongly acidic solution is typically used to fabricate gold nanotips in a quick and reliable manner. However, using an acidic solution could corrode the etching system, thereby posing hazardous problems. Therefore, both the corrosion of the etching system and human error induced by the conventional method considerably decrease the quality and reproducibility of the tip. In this study, we significantly increased the reproducibility of tip fabrication by automating the electrochemical etching system. In addition, we optimized the etching conditions for an etchant that comprised a KCl solution to which ethanol was added to overcome the limitations of the acidic etchant. The automated etching system significantly increases the yield rate of tip-fabrication reproducibility from 65 to 95%. The standard deviation of the radius of curvature decreased to 7.3 nm with an average radius of curvature of 30 nm. Accordingly, the automated electrochemical etching system might improve the efficiency of TERS.

Aperture based Raman spectroscopy on SiGe film structures with high spatial resolution

2008 ◽  
Vol 39 (4) ◽  
pp. 435-438 ◽  
Author(s):  
A. Mai ◽  
L. Zhu ◽  
M. Hecker ◽  
J. Rinderknecht ◽  
C. Georgi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Spatial Resolution ◽  
High Spatial Resolution

Assessment of Cereal Quality by Micro-Raman Analysis of the Grain Molecular Composition

2002 ◽  
Vol 56 (9) ◽  
pp. 1132-1138 ◽  
Author(s):  
Olivier Piot ◽  
Jean Claude Autran ◽  
Michel Manfait
Keyword(s):  
Molecular Basis ◽  
High Spatial Resolution ◽  
Microscopic Structure ◽  
Grain Texture ◽  
Wheat Grain ◽  
Raman Analysis ◽  
Cereal Grain ◽  
Confocal Raman Microspectroscopy ◽  
Confocal Raman

The development of confocal Raman microspectroscopy for cereal grain studies has led to breakthroughs in the understanding of the molecular basis of grain texture. The high spatial resolution and the nondestructive nature of the technique are its main assets, enabling more detailed analysis of the microscopic structure of wheat grain and investigation of the role of specific components involved in hardness. Hardness is the most relevant criterion in determining the suitability of wheat grain to be processed into flour. Our findings indicate that the α-helical secondary structure of protein could be associated with hardness.

Web Observatory Insights

2019 ◽  
Vol 15 (4) ◽  
pp. 52-68 ◽  
Author(s):  
Naif Radi Aljohani ◽  
Rabeeh Ayaz Abbasi ◽  
Fahad Mohammed Bawakid ◽  
Farrukh Saleem ◽  
Zahid Ullah ◽  
...  
Keyword(s):  
Big Data ◽  
Comparative Analysis ◽  
Deep Understanding ◽  
User Generated Content ◽  
Future Research ◽  
Privacy And Security ◽  
Common Practices ◽  
The Status ◽  
The Common ◽  
The Web

In the present era of Big Data, with continuously increasing amounts of user-generated content, it is becoming a challenge to understand the relation between the content that is available on the Web and the users who are generating that content. Researchers have come up with many ways to understand today's Web better. One of the recently introduced concepts is a Web observatory (WO). This article provides a deep understanding about web observatories. It discusses the status of existing WO systems. The article investigates and gathers the common practices of WOs. This research has implications for researchers and communities in the adoption of the WO concept. The article highlights the challenges of WOs, such as data crawling, privacy and security. It also provides future research and development directions. The article provides a comparative analysis of existing WOs. It discusses the architecture of WOs. It presents components of a WO in a coherent manner and finally provides insights into challenges and limitations of WOs.

scholarly journals Will Raman meet bacteria on Mars? An overview of the optimal Raman spectroscopic techniques for carotenoid biomarkers detection on mineral backgrounds

2015 ◽  
Vol 95 (2) ◽  
pp. 141-151 ◽  
Author(s):  
J.H. Hooijschuur ◽  
M.F.C. Verkaaik ◽  
G.R. Davies ◽  
F. Ariese
Keyword(s):  
Raman Spectroscopy ◽  
Spectroscopic Techniques ◽  
Time Resolved ◽  
Raman Analysis ◽  
Raman Spectroscopic ◽  
Technical Developments ◽  
Pure Compounds ◽  
Past Life ◽  
Detection Of Biomarkers ◽  
Ideal Technique

AbstractRaman spectroscopy appears to be an ideal technique for the initial detection of biomarkers, molecules that are potentially indicative of life on planetary bodies elsewhere in our solar system. Carotenoids are particularly useful biomarkers as they are used widely across the species, relatively resistant to breakdown and no inorganic source is known. They are used by microorganisms in their cell membranes for protection against UV radiation. In this paper we focus on the detection of carotenoids in microorganisms within a mineral matrix. We compare the Raman signatures of pure compounds with those of laboratory-made mixtures of β-carotene and minerals. Carotenoids covered by 2.5 mm of translucent calcite or 40 mm of transparent halite were detected using a conventional confocal Raman microscope. To improve sensitivity and hence detection levels, Raman measurements were successfully performed under resonant conditions. Raman analysis can be compromised by fluorescence interference. Data are presented to show how the contribution from the fluorescent background in the Raman spectra can be reduced when making use of gated detection in time-resolved Raman spectroscopy. Overall, this study demonstrates some of the potential of Raman spectroscopy as a method for the detection of (past) life signatures during future planetary missions without taking current technical limitations such as instrumental size into account as recent rapid technical developments suggest these limitations will be resolved in time.

Non-Intrusive Temperature Measurements in a Transonic Axial Compressor Using Spontaneous Rotational Raman Spectroscopy

2001 ◽  
Author(s):  
Roger Berreby ◽  
Alain Le Guével ◽  
Frédéric Grisch
Keyword(s):  
Raman Spectroscopy ◽  
High Spatial Resolution ◽  
Axial Compressor ◽  
Ccd Camera ◽  
High Repetition Rate ◽  
Experimental Investigations ◽  
Laser Technique ◽  
Experimental Parameters ◽  
Transonic Axial Compressor

Spontaneous rotational Raman spectroscopy was used to measure static temperature in a transonic axial compressor. This laser technique has the general advantages of such techniques, i.e. possibility of performing in-situ measurements with high spatial resolution and temporal resolution, and non-intrusiveness. The experimental investigations were performed just downstream the rotor for the design mass flow rate. The results are obtained from Raman scattering of air by using a high repetition rate pulsed Nd:YAG laser and a spectrally and spatially resolving detector system that consists of a triple spectrograph and a CCD camera. Raman Spectra presented here are integrated over 20 s. Profiles of temperature at various locations relative to the casing are presented and the measured temperatures are compared with theoretical values. Of great importance for the results is the accuracy of the technique, and a sensitivity analysis is performed to test the temperature on uncertainties in experimental parameters. It was shown that the absolute accuracy of temperature could be as low as ± 1 K in the 300 - 400 K operating range of interest.

Development of Multimedia Teaching Software Based on Self-Learning

2014 ◽  
Vol 998-999 ◽  
pp. 1689-1692
Author(s):  
Hua Ming Yu
Keyword(s):  
Learning Theory ◽  
Software Design ◽  
Procedural Knowledge ◽  
Deep Understanding ◽  
Classification Learning ◽  
Specific Design ◽  
Multimedia Teaching ◽  
The Status ◽  
Self Learning ◽  
Knowledge Classification

Some multimedia teaching software based on the content analysis of already existing problem in the design process to understand the current situation of multimedia teaching software design university. A deep understanding of the knowledge classification learning theory is proposed on the basis of the knowledge classification learning theory as the guiding theory of software design can change the status. And put forward the knowledge classification learning specific design methodology under the guidance of the declarative and procedural knowledge of autonomous learning and multimedia teaching software. Finally based on the above specific strategies to achieve the design these kinds of knowledge learning multimedia teaching software.

Composition Controlled Synthesis and Raman Analysis of Ge-Rich SixGe1–x Nanowires

2008 ◽  
Vol 8 (6) ◽  
pp. 3153-3157 ◽  
Author(s):  
P. Meduri ◽  
G. U. Sumanasekera ◽  
Z. Chen ◽  
M. K. Sunkara
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
Vapor Phase ◽  
Room Temperature ◽  
Nucleation And Growth ◽  
Accurate Estimation ◽  
Controlled Synthesis ◽  
Raman Analysis ◽  
Bulk Nucleation ◽  
Alloy Nanowires

Here, we report the synthesis of SixGe1–x nanowires with x values ranging from 0 to 0.5 using bulk nucleation and growth from larger Ga droplets. Room temperature Raman spectroscopy is shown to determine the composition of the as-synthesized SixGe1–x nanowires. Analysis of peak intensities observed for Ge (near 300 cm–1) and the Si-Ge alloy (near 400 cm–1) allowed accurate estimation of composition compared to that based on the absolute peak positions. The results showed that the fraction of Ge in the resulting SixGe1–x alloy nanowires is controlled by the vapor phase composition of Ge.

Evaluation of Curvature and Stress in 3C-SiC Grown on Differently Oriented Si Substrates

2011 ◽  
Vol 679-680 ◽  
pp. 137-140 ◽  
Author(s):  
Bernard Enrico Watts ◽  
Giovanni Attolini ◽  
Tullo Besagni ◽  
Matteo Bosi ◽  
Claudio Ferrari ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Raman Spectroscopy ◽  
Tensile Stress ◽  
Mechanical Deformation ◽  
Raman Analysis ◽  
Si Substrates ◽  
Temperature Ramps ◽  
Substrate Curvature

To assess deformation issues in SiC/Si, different pre-growth procedures were investigated, involving the addition of SiH4 to C3H8 during the temperature ramps used for the carbonization. 3C-SiC layers were deposited on (001) and (111) Si substrates by VPE. The mechanical deformation of the wafer was measured by makyoh, obtaining 2D maps of the entire wafers. For the same pre-growth procedures, the substrate curvature depends strongly on the orientation of the substrate, (001) or (111), being generally lower for (111) substrates. The deformation results were compared with XRD and Raman spectroscopy. Plastic deformation of the substrate was evidenced by XRD, while the presence of tensile stress is suggested by Raman analysis.

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