Coating gold nanoparticles to a glass substrate by spin-coat method as a surface-enhanced raman spectroscopy (SERS) plasmonic sensor to detect molecular vibrations of bisphenol-a (BPA)

Eskandari, Vahid,Hadi, Amin,Sahbafar, Hossein Techno-Press 2022 Advances in nano research Vol.13 No.5

Bisphenol A (BPA) is one of the chemicals used in monomer epoxy resins and polycarbonate plastics. The surface-enhanced Raman spectroscopy (SERS) method is precise for identifying biological materials and chemicals at considerably low concentrations. In the present article, the substrates coated with gold nanoparticles have been studied to identify BPA and control the diseases caused by this chemical. Gold nanoparticles were made by a simple chemical method and by applying gold salt and trisodium citrate dihydrate reductant and were coated on glass substrates by a spin-coat approach. Finally, using these SERS substrates as plasmonic sensors and Raman spectroscopy, the Raman signal enhancement of molecular vibrations of BPA was investigated. Then, the molecular vibrations of BPA in some consumer goods were identified by applying SERS substrates as plasmonic sensors and Raman spectroscopy. The fabricated gold nanoparticles are spherical and quasi-spherical nanoparticles that confirm the formation of gold nanoparticles by observing the plasmon resonance peak at 517 nm. Active SERS substrates have been coated with nanoparticles, which improve the Raman signal. The enhancement of the Raman signal is due to the resonance of the surface plasmons of the nanoparticles. Active SERS substrates, gold nanoparticles deposited on a glass substrate, were fabricated for the detection of BPA; a detection limit of 10-9 M and a relative standard deviation (RSD) equal to 4.17% were obtained for ten repeated measurements in the concentration of 10-9 M. Hence, the Raman results indicate that the active SERS substrates, gold nanoparticles for the detection of BPA along with the developed methods, show promising results for SERS-based studies and can lead to the development of microsensors. In Raman spectroscopy, SERS active substrate coated with gold nanoparticles are of interest, which is larger than gold particles due to the resonance of the surface plasmons of gold nanoparticles and the scattering of light from gold particles since the Raman signal amplifies the molecular vibrations of BPA. By decreasing the concentration of BPA deposited on the active SERS substrates, the Raman signal is also weakened due to the reduction of molecular vibrations. By increasing the surface roughness of the active SERS substrates, the Raman signal can be enhanced due to increased light scattering from rough centers, which are the same as the larger particles created throughout the deposition by the spin-coat method, and as a result, they enhance the signal by increasing the scattering of light. Then, the molecular vibrations of BPA were identified in some consumer goods by SERS substrates as plasmonic sensors and Raman spectroscopy.

라만분광학의 바이오메디컬 응용

정경복 한국물리학회 2017 새물리 Vol.67 No.6

Raman spectroscopy has attracted great interest as a powerful analytical tool that can be used to detect changes in the structure and the composition of biological samples (cells, tissues, biofluids, etc.) at the molecular level. Its high sensitivity and specificity, a small amount of sample preparation, and non- or minimally-invasive use have recently led to an increase in the number of biomedical applications of Raman spectroscopy. This paper reviews the recent biomedical applications of Raman spectroscopy, which are considered to be multi-functional and powerful toolkits for probing the biochemical properties of biomedical samples in medical science. The basic principles of Raman spectroscopy and surface-enhanced Raman scattering (SERS) are briefly introduced. Furthermore, the biomedical applications of Raman spectroscopy, including diagnostic assessment (orthodontic tooth movement), pharmacotherapy (antibiotic effect, cytotoxicity of tissue adhesive), medical device therapy (collagen cross-linking treatment for the restrain of progressive myopia), and finally in-vivo Raman diagnosis, are described. 라만 분광법은 분자수준에서 바이오 샘플 (세포, 조직, 체액 등)의 구조 및 조성 변화를 감지하는데 사용할 수 있는 강력한 분석 도구로써 매우 큰 관심을 모으고 있다. 높은 민감도와 특이성, 적은 양의 샘플준비, 비침습성 방법은 최근 라만 분광학의 바이오메디칼 응용의 증가로 이어졌다. 본 논문에서는 바이오 샘플의 생화학적 특성을 조사하기 위하여 다기능적이고 강력한 툴킷으로 간주되는 라만 분광학의 바이오메디칼 응용을 리뷰하였다. 라만 분광법과 표면증강라만산란 (surface enhanced Raman scattering, SERS)의 기본 원리를 소개하였고, 이를 이용한 바이오메디칼 응용: 진단 (치아교정 과정에서의 치아이동), 약물평가 (항생제 효과, 생체접착제의 세포 독성) 및 의료기기 요법 (근시 억제를 위한 콜라겐 교차 결합 치료), 라만진단 등의 라만분광학의 다양한 바이오메디칼 응용을 논하였다.

Comparative nondestructive measurement of corn seed viability using Fourier transform near-infrared (FT-NIR) and Raman spectroscopy

Ambrose, A.,Lohumi, S.,Lee, W.H.,Cho, B.K. Elsevier Sequoia 2016 Sensors and actuators. B Chemical Vol.224 No.-

The commercialization of agriculture has driven the need to ascertain the quality of agricultural inputs, especially seeds in order to optimize output and increase economic returns. Seed viability is a critical consideration for ensuring a reasonably high harvest. More often than not, farmers experience losses after a significant percentage of seeds fail to germinate after planting. The loss of seed viability may be due to a number of reasons such as overheating during drying, physical damage during post-harvest processing, and ageing during storage. It is therefore critical for seed companies to sufficiently inspect their products and uphold them to acceptable seed quality standards in order to gain credibility and ensure business sustainability. In this study, the Fourier transform near-infrared (FT-NIR) and Raman spectroscopy techniques were used for evaluating seed viability to investigate their comparative advantages with regard to the corn viability test and classification. The techniques were applied to white, yellow, and purple corns with 300 samples in each category. The 300 sample corn seeds were divided into two groups of 150 seeds each; one group was heat-treated using microwaving, and the other was used as the control. Sample spectra from treated and untreated corn seeds were collected using an FT-NIR spectrometer in the wave range of 1000-2500nm, and then Raman spectrometer in the wave range of 170-3200cm<SUP>-1</SUP>. The collected spectra were divided into training and testing sets, corresponding to 70% and 30% of the total, respectively for calibration and validation of the techniques. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to assess the spectral data from FT-NIR and Raman spectroscopy. The analysis results indicated that FT-NIR spectroscopy correctly classified viable and nonviable seeds for all the three categories of corns with a high accuracy of 100% and a predictive ability of more than 95%. Moreover, Raman spectroscopy demonstrated reasonably high classification accuracy with PLS-DA, but a significant number of seeds were overlapping when using PCA. In addition, an analysis of variance (ANOVA) indicated that the difference between treated and untreated corn seeds was not statistically significant (P<0.05). The study demonstrated that FT-NIR spectroscopy is superior to Raman spectroscopy in evaluating corn seed viability.

달 탐사를 위해 개발된 LIBS-Raman 통합 분광법을 이용한 CaCO₃, CaSO₄ 동소체 구분에 관한 연구

한동우,김대형,여재익 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

달과 화성 탐사 목적으로 LIBS(Laser-Induced Plasma Spectroscopy)와 Raman spectroscopy를 통합한 탑재체 연구가 진행되었다. 그 과정의 일환으로, 지구, 달, 화성의 토양 내에 함유량이 높은 것으로 알려진 Ca를 기반으로 한 암석들을 이용한 동소체(Polymorphs) 구분이 시도되었다. Nd:Yag(532nm, 6ns pulse width) 레이저를 CaCO₃(Calcite, Aragonite)와 CaSO₄(Gypsum, Anhydrite) 샘플에 조사해, LIBS, Raman 신호를 얻었으며 이에 사용된 에너지는 각각 20mJ/pulse(0.87 GW/cm²), 40mJ/pulse(1.7 GW/cm²)이다. 동일한 화학식을 가진 암석임에도 불구하고, 서로 다른 분자구조 및 밀도에 의해 나타나는 LIBS 신호 차이 및 그 원인을 분석함으로써, 원자와 이온 신호만 분석 가능하다고 알려진 LIBS의 활용범위를 넓힐 수 있었다. 더불어 Raman 신호를 이용한 검증을 통해, LIBS-Raman 통합 시스템의 상호보완적 탐사 성능을 한 단계 더 향상시킬 수 있었다. LIBS(Laser-Induced Plasma Spectroscopy) and Raman spectroscopy were tried to combined for payload to Moon and Mars. So some polymorphs of rocks which contain large amount of Ca were tried to be classified. We got LIBS and Raman signal by irradiating laser energy to CaCO₃(Calcite, Aragonite) and CaSO₄(Gypsum, Anhydrite) polymorphs. Each energy for LIBS was 20mJ/pulse(0.87 GW/cm²) and 40mJ/pulse(1.7 GW/cm²) was used for getting Raman signal. By analyzing different LIBS signal based on various molecular constructure and density in polymorphs, we enlarged utilization field of LIBS which is just known for getting atomic and ionic signal. Furthermore, we improved performance of LIBS-Raman combination system by proving Raman signal.

Advancing the experimental design for simultaneous acquisition of laser induced plasma and Raman signals using a single pulse

Choi, S.J.,Choi, J.J.,Yoh, J.J. Pergamon Press ; Elsevier Science Ltd 2016 Spectrochimica acta. Part B, Atomic spectroscopy Vol.123 No.-

<P>Simultaneous acquisition was performed of combined signals that show highly resolved and identifiable peaks of both LIBS and Raman signals. A LIBS-Raman combination using a single light source is a daunting task, because the energy required for Raman shift is relatively low, compared to the energy required for laser ablation. Here, we utilize an expanded-focused beam that allows simultaneous detection of the signals of laser induced plasma and Raman shift. A beam expander obtains the Raman signal with minimized interference from the plasma, and a focusing lens of small diameter generates strong laser induced plasma for LIBS. The position of the focusing lens can be adjusted to control the area of Raman scattering to ensure a strong Raman signal. In the proposed design, the key to minimized interference is to generate the Raman scattering apart from the plasma, which allows for sufficiently long gate width and wide area for Raman detection. Furthermore, axial relocation of the end of the optical fiber can easily optimize the Raman, LIBS, or combined Raman-LIBS signal. (C) 2016 Elsevier B.V. All rights reserved.</P>

Line-scan Raman imaging and spectroscopy platform for surface and subsurface evaluation of food safety and quality

Qin, J.,Kim, M.S.,Chao, K.,Schmidt, W.F.,Cho, B.K.,Delwiche, S.R. Applied Science Publishers 2017 Journal of food engineering Vol.198 No.-

<P>Both surface and subsurface food inspection is important since interesting safety and quality attributes can be at different sample locations. This paper pregents a multipurpose line-scan Raman platform for food safety and quality research, which can be configured for Raman chemical imaging (RCI) mode for surface inspection and spatially offset Raman spectroscopy (SORS) mode for subsurface inspection. In the RCI mode, macro-scale imaging was achieved using a 785 nm line laser up to 24 cm long with a push broom method. In the SORS mode, a 785 nm point laser was used and a complete set of SORS data was collected in an offset range of 0-36 mm with a spatial interval of 0.07 mm using one CCD exposure. The RCI and SOPS modes share a common detection module including a dispersive imaging spectrograph and a CCD camera, covering a Raman shift range from 674 to 2865 cm(-1). A pork shoulder and an orange carrot were used to test large-field-of-view (230 min wide) and high-spatial-resolution (0.07 mm/pixel) settings of the RCI mode for food surface evaluation. Fluorescence-corrected images at selected Raman peak wavenumbers Were used to view Raman-active analytes on the whole sample surfaces (e.g., fat on the pork shoulder and carotenoids over the carrot cross section). Also, three layered samples, which were created by placing carrot slices with thicknesses of 2, 5, and 8 mm on top of melamine powder, were used to test the SORS mode for subsurface food evaluation. Raman spectra from carrot and melamine were successfully resolved for all three layered samples using self-modeling mixture analysis. The line-scan Raman imaging and spectroscopy platform provides a new tool for surface and subsurface inspection for food safety and quality. Published by Elsevier Ltd.</P>

Raman 분광법을 이용한 $Li_{1-X}Al_{2X}Ta_{1-X}O_3$ 고용한계 분석

김정돈,홍국선,주기태,Kim, Chong-Don,Hong, Kug-Sun,Joo, Gi-Tae 한국분석과학회 1992 분석과학 Vol.5 No.1

강유전체인 $LiTaO_3$ 소재는 SAW filters나 IR sensors의 기본재료로 사용되고 있다. Dopant로서 $Al_2O_3$를 $LiTaO_3$에 일부 치환함으로써 유전 특성을 변화시키고 특히 용융점을 낮춤으로써 단결정 제조를 용이하게 한다. X-선 회절분석에 의한 격자상수 변화와 Raman spectroscopy의 band broadening을 측정한 결과 $LiTaO_3$에 대한 $Al_2O_3$의 고용한계가 $Li_{1-X}Al_{2X}Ta{1-X}O_3$에서 X=0.25mol이었으며, 고용한계 이상에서는 2차상인 $Al_2O_3$상이 XRD로 관찰되었다. Grain size에 의한 Raman band의 broadening을 고려하기 위하여 단결정과 소결체 $LiTaO_3$를 측정 비교하였다. The upper limit of solid solution of $Al_2O_3$ in $LiTaO_3$ was investigated using X-ray diffraction and Raman spectroscopy. By substituting cations in $LiTaO_3$ with $Al^{3+}$, the melting temperature was lowed and the ferroelectric properties can be improved. It is easier at lower temperature to fabricate the single crystal used for SAW filters and IR sensors. From the measured lattice constants and Raman band broadening, the solubility limit was X=0.25mol in $Li_{1-X}Al_{2X}Ta{1-X}O_3$, above which $Al_2O_3$ was obsered as a second phase. The Raman band of sintered $LiTaO_3$ was compared with that of the single crystal to see the effect of grain size on the band broadening.

A Novel Classification of Polymorphs Using Combined LIBS and Raman Spectroscopy

한동우,여재익,김대형,최수진 한국광학회 2017 Current Optics and Photonics Vol.1 No.4

Combined LIBS-Raman spectroscopy has been widely studied, due to its complementary capabilities asan elemental analyzer that can acquire signals of atoms, ions, and molecules. In this study, the classificationof polymorphs was performed by laser-induced breakdown spectroscopy (LIBS) to overcome the limitationin molecular analysis; the results were verified by Raman spectroscopy. LIBS signals of the CaCO3polymorphs calcite and aragonite, and CaSO4․ 2H2O (gypsum) and CaSO4 (anhydrite), were acquired usinga Nd:YAG laser (532 nm, 6 ns). While the molecular study was performed using Raman spectroscopy,LIBS could also provide sufficient key data for classifying samples containing different molecular densitiesand structures, using the peculiar signal ratio of 5s→4p for the orbital transition of two polymorphs thatcontain Ca. The basic principle was analyzed by electronic motion in plasma and electronic transition inatoms or ions. The key factors for the classification of polymorphs were the different electron quantitiesin the unit-cell volume of each sample, and the selection rule in electric-dipole transitions. The presentwork has extended the capabilities of LIBS in molecular analysis, as well as in atomic and ionic analysis.

Analysis of Raman Spectral Characteristics of Chemical Warfare Agents by Using 248-nm UV Raman Spectroscopy

최선경,정영수,고영진,이재환,남현우,이준오 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.3

Chemical warfare agents (CWAs) are extremely toxic and fatal to humans. It is required to quickly identify the released chemical agents and warn against the CWAs for protecting human life. The primary CWA contamination due to attacks occurs mostly on the ground surface, and Raman spectroscopy can quickly identify CWA on the surface in a non-contact manner. In particular, the interference can be reduced by avoiding the fluorescence of materials on the surface while increasing the Raman-scattering intensity with the excitation light source of deep ultra violet (UV) smaller than 250 nm. In this study, the Raman spectra of 18 chemical agents, including major CWAs, were measured using a Raman spectroscopy system with 248-nm deep-UV light source, and the spectral characteristics of each agent were analyzed. From the results, we confirmed that deep-UV Raman spectroscopy could be the main method for quickly and accurately detecting and identifying CWA contamination.

Determination of Ethanol in Blood Samples Using Partial Least Square Regression Applied to Surface Enhanced Raman Spectroscopy

Gune? Acikgoz,Berna Hamamci,Abdulkadir Yildiz 한국독성학회 2018 Toxicological Research Vol.34 No.2

Alcohol consumption triggers toxic effect to organs and tissues in the human body. The risks are essentially thought to be related to ethanol content in alcoholic beverages. The identification of ethanol in blood samples requires rapid, minimal sample handling, and non-destructive analysis, such as Raman Spectroscopy. This study aims to apply Raman Spectroscopy for identification of ethanol in blood samples. Silver nanoparticles were synthesized to obtain Surface Enhanced Raman Spectroscopy (SERS) spectra of blood samples. The SERS spectra were used for Partial Least Square (PLS) for determining ethanol quantitatively. To apply PLS method, 920~820 cm<SUP>−1</SUP> band interval was chosen and the spectral changes of the observed concentrations statistically associated with each other. The blood samples were examined according to this model and the quantity of ethanol was determined as that: first a calibration method was established. A strong relationship was observed between known concentration values and the values obtained by PLS method (R² = 1). Second instead of then, quantities of ethanol in 40 blood samples were predicted according to the calibration method. Quantitative analysis of the ethanol in the blood was done by analyzing the data obtained by Raman spectroscopy and the PLS method.