Interview of the Month

Measuring Wheat Flour Purity Using Quantitative NIR Chemical Imaging

Isolating material of commercial value from solid natural products presents a challenge for many spectroscopic techniques. Near-infrared (NIR) chemical imaging makes it possible to obtain spectra from individual pixels within a field of view for analysis of complex, heterogeneous mixtures. A team at Kansas State University, led by David Wetzel, has been applying this approach to multiple applications, including the analysis of wheat. In particular, the group has work on alternative methods for the determination of flour and milling stream purity, because outdated methods such as mineral ash residue impurity analysis do not properly reflect the quality of the final products of milling and are dependent upon the soil where the wheat is milled. Mark Boatwright, who is studying for his doctorate under Wetzel, talked to Spectroscopy about some of this work.

Quantum Mechanics

This series of installments from David Ball’s excellent “Baseline” column discusses the relevance of quantum mechanics for spectroscopy and why it is important for spectroscopists to know the basics.

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The Benzene Fingers, Part II: Let Your Fingers Do the Walking Through the Benzene Fingers

By Brian C. Smith

The benzene fingers are a series of overtone and combination bands that can be used to distinguish substituted benzene rings when other methods do not work.

Kinetic Imaging of Epoxy Curing

By Stephan Woods, David Drapcho, Mike Bradley

By using an array detector in conjunction with ultrafast mapping, one can produce kinetic chemical imaging to monitor the curing process in a two-part epoxy resin.

FT-IR Microscopic Analysis of Polymer Laminate Samples Including Transmission and ATR Spectroscopy

By Richard A. Larsen, Ken-ichi Akao, Jun Koshoubu, Kohei Tamura, Hiroshi Sugiyama

The value of combining ATR and transmission spectra for the analysis of polymer laminates is illustrated here through the analysis of a multilayer polymer laminate from a food packaging sample.

Purity Analysis of Adulterated Essential Oils by FT-IR Spectroscopy and Partial-Least-Squares Regression

By Brianda Elzey, Victoria Norman, Jamira Stephenson, David Pollard, Sayo O. Fakayode

This study explores the use of FT-IR spectroscopy and PLS regression for the authentication of essential oils—wintergreen oil, tea tree oil, rosemary oil, and lemon eucalyptus oil—adulterated with either lemongrass oil or peppermint oil.

Vibrational Spectroscopic Discrimination of Herbal Medicines: Polygala senega, Polygala tenuifolia, and Glinus oppositifolius

By Cornelia K. Pezzei, O.M.D. Lutz, V.A. Huck-Pezzei, Sarah Kuderer, Brigitte Kopp, Christian W. Huck

A simple and rapid authentication method is presented for herbal medicine samples using commercially available mid-infrared and near-infrared benchtop spectrometers as well as using a handheld NIR device.


Protein Secondary Structure Determination Using Drop Coat Deposition Confocal Raman Spectroscopy

By Jeremy Peters, Anna Luczak, Varsha Ganesh, Eugene Park, Ravi Kalyanaraman

This technique has the potential to predict α-helix and β-sheet protein structures accurately and to predict other structures with a degree of accuracy previously achieved only with X-ray crystallography. The technique also has many advantages, including quick data acquisition, low sample requirement, and no special processing of raw data other than peak fitting.

Matthew Baker, Winner of Spectroscopy’s Inaugural Emerging Leader in Molecular Spectroscopy Award, Focuses on Clinical IR and Raman Applications

By Spectroscopy Editors

Spectroscopy is proud to have created a new award, the Emerging Leader in Molecular Spectroscopy Award. As its name implies, the award recognizes a young scientist, and it is designed to encourage the next generation of molecular spectroscopists. Matthew Baker, the winner of the inaugural Emerging Leader in Molecular Spectroscopy Award, is a senior lecturer in chemistry at the University of Strathclyde, in Glasgow, Scotland. At Strathclyde, Baker leads research to advance the application of analytical chemistry to real-world problems in a variety of areas, including the biomedical, clinical, defense, and security fields. His main focus is the development of spectroscopic and spectrometric molecular pathology, disease diagnosis, and the detection of pathogenic bacteria and toxic chemicals. In particular, Baker has pioneered the use of vibrational spectroscopy for clinical diagnostics.

Library-Based Screening of Pharmaceutical Materials by Handheld Raman and Near-Infrared Spectrometers

By Chelliah V. Navin, Latevi S. Lawson, Jason D. Rodriguez

A report on screening common anti-infective drugs using spectral libraries built and transferred from laboratory-based instruments to handheld near-infrared and Raman spectrometers

The Versatility of Portable Raman in Process Development

By Thomas Padlo, Katherine Bakeev

A demonstration of the ability for portable Raman spectroscopy coupled with univariate and multivariate analysis tools in the process development stage to gain insight and process understanding of chemical reactions


Overview of High-Efficiency Transmission Gratings for Molecular Spectroscopy

By Thomas Rasmussen

This article provides a basic overview of the capabilities of transmission gratings optimized for molecular spectroscopy.

Scattering Impact Analysis and Correction for Leaf Biochemical Parameter Estimation Using Vis–NIR Spectroscopy

By Qianxuan Zhang, Qingbo Li, Guangjun Zhang

Simulated leaf spectral data were generated to analyze scattering impact and then compared to experimental data to validate the conclusions of the simulation.

An Integration of Modified Uninformative Variable Elimination and Wavelet Packet Transform for Variable Selection

By Di Wu, Xiaojing Chen, Yong He

The wavelet packet transform (WPT) combined with the modified uninformative variable elimination (MUVE) method (WPT–MUVE) is proposed to select variables for multivariate calibration of spectral data.

Analysis of Fructose, Glycine, and Triglycine Using HPLC UV-vis Detection and Evaporative Light-Scattering Detection

By A.B. de Haan, R. Wijntje, H.A.J.M. Bevers

The development of a method for the simultaneous determination of glycine, triglycine and fructose using UV–vis and evaporative light-scattering detection (ELSD) is described. This was necessary as part of a research project dealing with the recovery of functional peptides from aqueous streams on an industrial scale using adsorption or related technologies. Fructose is barely detectable by UV–vis as it lacks detectable functionalities, while glycine and triglycine are both UV–vis sensitive. An NH2 phase was chosen as a column and separation was obtained within seven minutes on a 250 X 4.6 mm column. Limits of detection are approximately 40 mg fructose/L, 4 mg glycine/L and 0.05 mg triglycine/L. Calibration functions are linear in a range of 40–1400 mg/L for fructose, 5–200 mg/L for glycine and 0.5–70 mg/L for triglycine.

Spectroscopy in Space: Hubble and the Cosmic Origins Spectrograph

By Spectroscopy Editors

In an upcoming spacewalk, shuttle astronauts will swap the Corrective Optics Space Telescope Axial Replacement (COSTAR) device for the new Cosmic Origins Spectrograph (COS).

Peer-Reviewed Articles

Protein Secondary Structure Determination Using Drop Coat Deposition Confocal Raman Spectroscopy

By Jeremy Peters, Anna Luczak, Varsha Ganesh, Eugene Park, Ravi Kalyanaraman

This technique has the potential to predict α-helix and β-sheet protein structures accurately and to predict other structures with a degree of accuracy previously achieved only with X-ray crystallography. The technique also has many advantages, including quick data acquisition, low sample requirement, and no special processing of raw data other than peak fitting.

Shedding New Light on Forensic Timelines

By Maggie O’Connor, Kiana Jansen, Joseph Hodge, Christine O’Brien, Isaac Pence, Anita Mahadevan-Jansen

Raman spectroscopy has the potential to accurately and nondestructively determine the age of a bloodstain for use in criminal investigations.

Emerging Trends and Opportunities in Discrete-Frequency Infrared and Raman Spectroscopic Imaging

By Tomasz P. Wrobel, Matthew R. Kole, Rohit Bhargava

Recent 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.

Preparation of Pharmaceutical Samples for Elemental Impurities Analysis: Some Potential Approaches

By Nancy Lewen

As analysts prepare to meet the requirements of the new United States Pharmacopeia and International Conference on Harmonization standards on elemental impurities, they need to understand how to choose the most suitable sample preparation approach.


Spectroscopy at AOAC

The 2016 annual meeting of the Association of Analytical Communities (AOAC), taking place September 18–21 in Dallas, Texas, will include scientific sessions discussing the use of spectroscopy and mass spectrometry techniques in the analysis of food, dietary supplements, and pharmaceuticals.

Nonprofit Brings Hands-On Laboratory Experience to Young Students to Promote STEM Careers

In the United States, a lack of qualified candidates for jobs in science, technology, engineering, and math (STEM) underscores an urgent need for educators to find ways to draw students into these areas of study.

Indiana University School of Informatics and Computing Awarded $1M Grant from NIH

The National Institutes of Health (NIH) has awarded $1.18 million to faculty at the Indiana University School of Informatics and Computing at Indiana University–Purdue University Indianapolis and the IU School of Medicina (Indianapolis, Indiana) for a research collaboration that unites two cutting-edge technologies in the discovery and analysis of proteoforms.

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Using Elemental Analysis Techniques to Detect Metals in Counterfeit Cigarettes and Water Samples and Promote Environmental Education

By Spectroscopy Editors

The analysis of metals using inductively coupled plasma–mass spectrometry (ICP-MS), ICP-atomic emission spectroscopy (ICP-AES), and atomic absorption can serve many purposes in environmental, health, and forensic studies. Yi He, a chemistry professor at John Jay College of Criminal Justice at The City University of New York, has been using these elemental analysis techniques for fingerprinting and provenance of counterfeit cigarettes and as an educational tool. Here, she discusses some of that work.

New Approaches in Sample Preparation and Precise Multielement Analysis of Crude Oils and Refined Petroleum Products Using Single-Reaction-Chamber Microwave Digestion and Triple-Quadrupole ICP-MS

By John Casey, Yongjun Gao, Robert Thomas, Weihang Yang

Using this method, complete elemental recovery and removal of organic matrices can be achieved safely and up to 57 elements can be determined in oils with good accuracy and precision. The removal of organic matrices during digestion helps limit the formation of polyatomic spectral interferences and also improves instrument stability.

What Modeling Reveals About the Properties of an Inductively Coupled Plasma

By Spectroscopy Editors

Annemie Bogaerts and Maryam Aghaei of the University of Antwerp, Belgium, are carrying out computational modeling to examine how various properties of the ICP, such as gas flow path lines and ionization effects, are affected by various factors—such as gas flow rates, applied power, and even the very presence of a mass spectrometry sampler. Using their developed model, one can predict optimum conditions for specific analyses.

How to Improve Analytical Figures of Merit of Hard-To-Ionize Elements in ICP-Based Techniques

By Spectroscopy Editors

Matrix effects in ICP-OES and ICP-MS often cause signal suppression, but can lead to signal enhancement as well. Guillermo Grindlay of the University of Alicante, in Spain, discusses his work to better understand under what conditions these matrix effects occur and what mechanisms are involved.

Questioning the Relationship Between Analyte Ion Mass and ICP-MS Matrix Effects

By Spectroscopy Editors

New studies conducted by Shi Jiao and John Olesik at The Ohio State University have important implications for understanding the fundamental causes of matrix effects in ICP-MS, and for the choice of internal standards.

Mass Spectrometry

Nontargeted Metabolite Profiling in Next-Generation Plant Breeding: A Case Study in Malting Barley

By Adam Heuberger, Corey D. Broeckling, Jessica Prenni

The power of nontargeted metabolite profiling is illustrated in a study focused on the determination of molecular markers in malting barley that are predictive of desirable malting quality for brewing applications. The metabolite extraction, detection, and analysis methods are high throughput and reproducible, and therefore, this approach represents a practical addition to the plant breeder’s molecular toolbox.

A Fast Method for Targeted Allergen Screening and Nontargeted Characterization for Personal Care Products

By Elizabeth Humston-Fulmer

A gas chromatography–time-of-flight mass spectrometry method was developed to screen for and quantify regulated allergens in approximately 5 min. This method used a short and narrow chromatographic column along with mathematical deconvolution of the TOF-MS data to separate the target allergens from each other in the standards and from matrix interference in samples.

Comprehensive Fragrance Profiling of Ginger, Wintergreen, and Rosemary Essential Oils by GC–TOF-MS with Soft Electron Ionization

By David Barden, Laura McGregor, Steve Smith

This study demonstrates that GC–TOF-MS can be a useful approach to generate comprehensive fragrance profiles of essential oils. Peak deconvolution enables discrimination between closely eluted compounds, and soft electron ionization, assisted by comparison of ion ratios, makes it possible to discriminate between isomeric monoterpenes with very similar mass spectra at conventional 70-eV ionization energies.

Quantitation of Albumin and Creatinine in Urine by MALDI-TOF Mass Spectrometry

By Stephen J. Hattan, Kenneth C. Parker, Marvin L. Vestal, Jane Y. Yang, David A. Herold, Mark W. Duncan

This MS-based method represents a simple, fast, and attractive alternative to current immunoassay-based methods for the quantitation of albumin and creatinine in urine. This protocol enables the direct detection and measurement of the intact analytes from the same sample preparation, requiring only a 10-fold dilution of a urine sample into a MALDI-TOF matrix solution.

Review of the 64th Conference on Mass Spectrometry and Allied Topics

By Cindy Delonas

We present a brief review of this year's ASMS conference, which took place June 5–9 in San Antonio, Texas.

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