Spectroscopy Top 10 Articles of the Month (May 2026)

Each article has been selected based on the number of successful DOI page views by readers as reported by [email protected]. The articles showcase key developments and insights in spectroscopy and chromatography. Spectroscopy covers the main topics of electronic spectroscopy, vibrational spectroscopy, magnetic resonance, imaging techniques, atomic spectroscopy, and data analysis and integration. LCGC covers most aspects of liquid and gas chromatography, mass spectrometry, and related technical aspects of separation science.

This month we highlight articles from the ever-popular Spectroscopy and LCGC International columns and feature articles.

1. Infrared Spectroscopy of Polymers XIII: Polyurethanes

Author: Brian C. Smith

This installment in the popular polymer spectroscopy series examines the infrared spectra of polyurethanes. The article reviews the characteristic spectral features associated with urethane functional groups and compares polyurethane spectra with those of related polyamides. Practical examples illustrate the identification of polyurethane materials used in foam products, elastomers, coatings, and adhesives. The article emphasizes how carbonyl and N–H absorptions can be used to distinguish polyurethane materials and understand polymer structure.

2. The Infrared Spectra of Polymers II: Polyethylene

Author: Brian C. Smith

Polyethylene remains one of the most important commercial polymers and serves as an excellent model system for learning polymer infrared spectroscopy. This article continues the discussion of polyethylene spectral interpretation, showing how synthesis methods affect polymer morphology and spectroscopic behavior. Particular attention is given to crystalline splitting and methylene rocking vibrations, illustrating how subtle spectral changes reveal structural differences in polyethylene materials.

3. Infrared Spectroscopy of Polymers VIII: Polyesters and the Rule of Three

Author: Brian C. Smith

This article introduces the infrared spectroscopy of ester-containing polymers and presents the author's “Rule of Three” approach for interpreting polyester spectra. Important industrial polymers, including polyethylene terephthalate (PET), are examined in detail. The article reviews ester-group spectroscopy and demonstrates how characteristic carbonyl and C–O stretching bands facilitate the identification and analysis of polyester materials.

4. Tackling PFAS Complexity with HRMS and Bioanalytical Techniques

Authors: Carrie McDonough and Wesley Scott

Per- and polyfluoroalkyl substances (PFAS) continue to present major analytical challenges because of their structural diversity and environmental persistence. This article discusses how high-resolution mass spectrometry (HRMS) and emerging bioanalytical methods can be combined to improve PFAS detection, identification, and risk assessment. The authors highlight current analytical workflows and discuss future directions for comprehensive PFAS characterization.

5. Infrared Spectroscopy of Polymers X: Polyacrylates

Author: Brian C. Smith

Acrylic polymers represent a large and commercially important family of materials. This article focuses on polyacrylates, especially polymethyl methacrylate (PMMA), commonly known as Plexiglas. The discussion demonstrates how infrared spectroscopy can distinguish PMMA, copolymers, and polymer blends through characteristic ester and methyl-group vibrations. Applications in materials identification and quality control are emphasized.

6. A Review of the Latest Research Applications Using FT-IR Spectroscopy

Author: Jerome Workman, Jr.

This review surveys recent developments in Fourier transform infrared (FT-IR) spectroscopy and highlights emerging applications across pharmaceutical analysis, materials characterization, environmental monitoring, biomedical research, and process analytics. The article illustrates how advances in instrumentation, software, and chemometric methods continue to expand the capabilities and relevance of FT-IR spectroscopy.

7. Infrared Spectroscopy of Polymers III: Hydrocarbon Polymers

Author: Brian C. Smith

Hydrocarbon polymers constitute one of the largest classes of industrial plastics. This article explains the infrared spectral characteristics of polymers composed primarily of hydrocarbon chains. Through examples and practical interpretation techniques, readers learn how to identify polymer structure using characteristic C–H stretching and bending vibrations, as well as diagnostic spectral patterns associated with common hydrocarbon-based materials.

8. Interpretation of Raman Spectrum of Proteins

Author: Fran Adar

Proteins present complex Raman spectra that contain information about molecular structure, conformation, and biological function. This article provides a practical guide to interpreting protein Raman spectra, including assignments of amide bands, side-chain vibrations, and structural markers. The discussion demonstrates how Raman spectroscopy can be used to investigate protein folding, aggregation, and biochemical interactions.

9. Pressure–Enhanced Liquid Chromatography as a Suitable Approach to Improve Selectivity for Large Molecule Separations

Authors: Honorine Lardeux, Davy Guillarme, Mateusz Imiołek, and co-workers

The separation of large biomolecules remains a major challenge in liquid chromatography. This article investigates pressure-enhanced liquid chromatography as a strategy for improving selectivity and resolution. The authors demonstrate how pressure can alter chromatographic retention behavior and provide improved separations for complex large-molecule samples, offering new opportunities for pharmaceutical and biopharmaceutical analysis.

10. Purification and Isolation of Cannabinoids: Current Challenges and Perspectives

Authors: Simona Felletti, Greta Compagnin, Yannick Krauke, and co-workers

The rapid growth of cannabinoid research and commercialization has increased demand for effective purification technologies. This article reviews current approaches for cannabinoid isolation and purification, discusses analytical and regulatory challenges, and examines future opportunities for improving separation efficiency, product purity, and process scalability.

References

1. Smith, B. C. Infrared Spectroscopy of Polymers XIII: Polyurethanes. Spectroscopy 2023, 38 (7), 14–16. DOI: 10.56530/spectroscopy.fn3378a3.
2. Smith, B. The Infrared Spectra of Polymers II: Polyethylene. Spectroscopy 2021, 36 (9), 24. DOI: 10.56530/SPECTROSCOPY.XP7081P7.
3. Smith, B. C. Infrared Spectroscopy of Polymers VIII: Polyesters and the Rule of Three. Spectroscopy 2022, 37 (10), 25–28. DOI: 10.56530/spectroscopy.ta9383e3.
4. McDonough, C.; Scott, W. Tackling PFAS Complexity with HRMS and Bioanalytical Techniques. LCGC Supplements 2023, 41 (s9), 12–16. DOI: 10.56530/lcgc.na.nr4267c9.
5. Smith, B. C. Infrared Spectroscopy of Polymers X: Polyacrylates. Spectroscopy 2023, 38 (1), 10–14. DOI: 10.56530/spectroscopy.mi9381w4.
6. Workman, J., Jr. A Review of the Latest Research Applications Using FT-IR Spectroscopy. Spectroscopy Supplements 2024, 39 (s8), 22–28. DOI: 10.56530/spectroscopy.ak9689m8.
7. Smith, B. C. Infrared Spectroscopy of Polymers III: Hydrocarbon Polymers. Spectroscopy 2021, 36 (11), 22-25. DOI: 10.56530/spectroscopy.mh7872q7
8. Adar, F. Interpretation of Raman Spectrum of Proteins. Spectroscopy 2022, 37 (2), 9–13, 25. DOI: 10.56530/spectroscopy.lo2270l5.
9. Lardeux, H.; Guillarme, D.; Imiołek, M.; et al. Pressure–Enhanced Liquid Chromatography as a Suitable Approach to Improve Selectivity for Large Molecule Separations. LCGC Supplements 2023, 41 (s4), 28–34. DOI: 10.56530/lcgc.na.ts6090k5.
10. Felletti, S.; Compagnin, G.; Krauke, Y.; et al. Purification and Isolation of Cannabinoids: Current Challenges and Perspectives. LCGC Europe 2023, 36 (4), 122–131. DOI: 10.56530/lcgc.eu.jp5571c5.