April 23rd 2024
To improve the robustness and accuracy of logistic regression identification method, a new Raman spectroscopy identification method was proposed that combines a distributionally robust optimization technique and fused lasso technique with logistic regression. Then, Raman spectroscopy was used to analyze two types of dairy products that were collected for anti-jamming identification testing to verify the effectiveness of the new method.
December 1st 2023
Characterization of Glitter Cosmetic Particles Using FT-IR Spectroscopy
November 1st 2018Glitter particles from cosmetics may transfer during personal assaults, and thus glitter may be useful as a forensic tool. In this study, glitter samples were analyzed using ATR–FT-IR in an attempt to develop a characterization scheme to aid in the identification of these particles.
Enhanced Protein Structural Characterization Using Microfluidic Modulation Spectroscopy
July 1st 2018This article introduces a new IR technique, microfluidic modulation spectroscopy (MMS), that is designed to address the needs in biotherapeutics, and presents data from measurements of commercially available proteins.
Testing Electronic Device Components for RoHS/WEEE Compliance Using Microwave Digestion and ICP-OES
January 1st 2018The combination of microwave sample preparation and ICP-OES is examined to meet the challenges of measuring a suite of heavy metals in a wide range of electronic components for RoHS/WEEE compliance.
The 2018 Emerging Leader in Atomic Spectroscopy Award
January 1st 2018John M. Cottle, the winner of Spectroscopy’s 2018 Emerging Leader in Atomic Spectroscopy Award, is a leader in the development of novel laser-ablation inductively coupled plasma–mass spectrometry measurements and their application to tectonic questions in convergent orogens. His three breakthrough measurement methods using LA-ICP-MS for geochemical data collection are breaking new ground in Earth science.
Morphologically Directed Raman Spectroscopic Analysis of Forensic Samples
Can morphologically directed Raman spectroscopy obtain more discriminatory information from forensic samples than current tools?
Surface-Enhanced Raman Spectroscopy: From Concept to Practical Application
November 1st 2017In the last decade, numerous SERS substrates have been developed, but it is difficult to compare and validate their plasmonic performance. In this overview, the authors discuss the three physical parameters of any new SERS platform that must be measured-morphological characterization, optical scattering (far-field response), and near-field properties-and future prospects for the development of new SERS platforms.
Determination of Rare Earth Elements in Geological and Agricultural Samples by ICP-OES
This method demonstrates that ICP-OES is a suitable alternative to ICP-MS for the determination of rare earth elements in geological and agricultural samples
Tandem LA–LIBS Coupled to ICP-MS for Comprehensive Analysis of Tumor Samples
October 1st 2017This method demonstrates the excellent suitability of a multimodal approach that combines LA-ICP-MS with LIBS for the analysis of tumor samples, particularly when the standalone techniques cannot detect all the elements of interest.
A Priori Performance Estimation of Spatial Filtering in Raman Backscattering Experiments
May 1st 2017A straightforward numerical approach to estimate the performance of a spatial filter in Raman backscattering spectroscopy has been developed. This approach enabled the authors to determine an optimal hole diameter that balances spatial resolution and signal intensity.
Pump–Probe Microscopy: Theory, Instrumentation, and Applications
April 1st 2017Excited state dynamics provides an intrinsic molecular contrast of samples examined. These dynamics can be monitored by pump probe spectroscopy which measures the change in transmission of a probe beam induced by a pump beam. With superior detection sensitivity, chemical specificity and spatial-temporal resolution, pump probe microscopy is an emerging tool for functional imaging of non-fluorescent chromophores and nanomaterials. This article reviews the basic principle, instrumentation strategy, data analysis methods, and applications of pump probe microscopy. A brief outlook is provided.
Recent Advances in Pharmaceutical Analysis Using Transmission Raman Spectroscopy
April 1st 2017This article reviews recent advances in the application of Transmission Raman Spectroscopy (TRS) to pharmaceutical analysis. The TRS technique overcomes subsampling limitations of conventional Raman spectroscopy and enables rapid non-invasive volumetric analysis of intact pharmaceutical tablets and capsules in a quantitative manner with relevance to quality and process control applications. Although only recently introduced to this area its uptake and the breadth of applications are rapidly growing with regulatory approvals for use of this technology in quality control of manufactured pharmaceutical products recently being granted.
Frontiers of Far-Ultraviolet Spectroscopy in the Solid and Liquid States
February 1st 2017This article reviews the state-of-the-art of far-ultraviolet (FUV) spectroscopy of solid and liquid phases. FUV spectroscopy is rich in information about electronic structure and transitions of a molecule, but this region has been employed to investigate mainly for the electronic states and structure of gas molecules because the absorptivity is very high in the FUV region. To overcome this difficulty we have developed a totally new FUV spectrometer based on the attenuated total reflection (ATR) technique. ATR-FUV spectroscopy has paved a new avenue for condensed matter FUV spectroscopy. This article demonstrates that FUV holds considerable promise not only in basic science such as studies of electronic structure of molecules, hydrogen bonding, hydration, and adsorption of water and aqueous solutions, but also practical applications, such as on-line analysis, geochemical and environmental analyis, semiconductor research and surface analysis.
Protein Secondary Structure Determination Using Drop Coat Deposition Confocal Raman Spectroscopy
October 1st 2016The accurate determination of protein structure is integral to the medical and pharmaceutical communities’ ability to understand disease, and develop drugs. Current techniques (CD, IR, Raman) for protein structure prediction provide results that can be poorly resolved, while high resolution techniques (NMR, X-ray crystallography) can be both costly and time-consuming. This work proposes the use of drop coat deposition confocal Raman spectroscopy (DCDCR), coupled with peak fitting of the Amide I spectral region (1620–1720 cm-1) for the accurate determination of protein secondary structure. Studies conducted on BSA and ovalbumin show that the predictions of secondary structure content within 1% of representative crystal structure data is possible for model proteins. The results clearly demonstrate that DCDCR has the potential to be effectively used to obtain accurate secondary structure distributions for proteins.
Shedding New Light on Forensic Timelines
September 1st 2016The development of novel, nondestructive technologies for rapid analysis of evidence discovered at crime scenes is pertinent to our criminal justice system to solve the millions of violent crimes that occur each year. Without a witness, establishing the precise timeline of a crime is difficult. Therefore, technologies based on sensitive, nondestructive techniques are needed to evaluate evidence and create such a timeline. We propose the use of Raman spectroscopy to analyze the age of bloodstains for potential use as a forensics tool. Previous studies have revealed Raman spectroscopy is sensitive to changes in blood analyte concentration and different oxidative states of hemoglobin. Raman spectroscopy could allow for rapid comparison of spectra from blood stains of unknown age to spectra of known age with high temporal accuracy. Though further investigation into other substrates and biochemical components should be performed, our study reveals Raman spectroscopy has the potential to accurately and nondestructively determine the age of a bloodstain for use in criminal investigations.
Analysis of the Brill Transition and Reversible Brill Transition in Nylon 6,6 by Raman Spectroscopy
July 1st 2016This article verified the Brill transition in nylon 6,6 by Raman spectroscopy through heating and cooling processes of the sample. When nylon is heated at around 160 C a crystalline phase transition occurs from a triclinic structure at room temperature to a pseudohexagonal structure above that temperature. This phase transition is known as the Brill Transition. With temperature-dependent Raman scattering measurements, it was possible to determine the vibrational behavior of nylon 6,6 during the Brill transition, and consequently to identify the main Raman bands associated with the Brill transition.
Emerging Trends and Opportunities in Discrete-Frequency Infrared and Raman Spectroscopic Imaging
June 1st 2016Recent advances in instrumentation have enabled new forms of vibrational chemical imaging, including discrete frequency infrared (DFIR) microscopy and stimulated Raman scattering (SRS) microscopy. These technologies may represent a fundamental shift in how we approach spectroscopic imaging: rather than collecting full spectra which contain redundant information, measuring a few important spectral frequencies may enable significant gains in speed, throughput, signal to noise ratio, and/or image quality. For infrared microscopy, these advantages may be compounded by High Definition IR microscopy. Here we discuss recent advances in infrared and nonlinear Raman imaging through the lens of 'discrete frequency' approaches, including several examples of applications and critical issues in instrumentation that are likely to be dominating research themes in the near future.
Preparation of Pharmaceutical Samples for Elemental Impurities Analysis: Some Potential Approaches
April 1st 2016The use of atomic spectroscopy techniques and sample preparation procedures is something that is not as routine in the pharmaceutical industry as are chromatography-based techniques and sample preparation procedures. With new requirements being implemented regarding elemental impurities by the United States Pharmacopoeia (USP) and International Conference on Harmonization (ICH), analysts in the pharmaceutical industry are, in many cases, working to determine how best to analyze their samples. Sample preparation techniques that can be used for pharmaceutical samples are the same ones that have been used by other industries for many years. This paper will provide a brief overview of potential techniques.