Best of the Week: Opposition Surge Effect in Astronomy, Analyzing Soil in the Amazon

This week, Spectroscopy published a variety of articles highlighting recent studies in several application areas, including environmental analysis, astronomy, and biomolecular spectroscopy. Key techniques highlighted in these articles include visible, near-infrared, and short-wave infrared (Vis-NIR-SWIR) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Happy reading!

Exploring the Key Drivers of the Opposition Surge Effect in Astronomy

In a recent interview with Spectroscopy, Leonardos “Leo” Gkouvelis of Ludwig Maximilian University (Munich, Germany) discussed the roles of shadow hiding and coherent back scattering in astronomy. Shadow hiding occurs when angled light reduces visible shadows, making surfaces appear brighter, while coherent back scattering arises from constructive interference of light waves, further enhancing brightness (1). Together, these phenomena explain the opposition effect, where celestial bodies like the moon and exoplanets appear brighter when viewed from certain angles. Gkouvelis emphasized the importance of mathematical modeling of synthetic spectra to account for these effects, particularly for exoplanet studies where direct observations are limited (1).

Spectroscopic Investigation of Charge Transfer Interaction Between Five Antibiotics Depending on Density Functional Theory

This peer-reviewed study investigates charge transfer (CT) complexes between hydrogen peroxide (H₂O₂) and five antibiotics, which include trimethoprim (TMP), norfloxacin (NOR), ofloxacin (OFL), ciprofloxacin (CIP), and sulfamerazine (SMR), using density functional theory (DFT) (2). Theoretical analysis revealed key excitation wavelengths responsible for CT transitions, influencing the UV-Vis spectra of each complex. HOMO-LUMO energy calculations confirmed CT occurrence and provided insight into molecular interactions (2). Complementary experimental characterization using UV-Vis, IR, and ¹H NMR spectroscopy identified bonding sites between H₂O₂ and the antibiotics (2). Together, the results establish a theoretical and experimental foundation for understanding drug-receptor binding mechanisms via CT complex formation.

Using Reflectance Spectroscopy and Cloud Computing in Analyzing Soil

A study published in the Journal of Environmental Management by researchers from the University of São Paulo and the Federal University of Amazonas highlights the potential of spectroscopic techniques to revolutionize soil analysis in the Amazon River Basin (ARB). By applying visible, near-infrared, and short-wave infrared (Vis-NIR-SWIR) spectroscopy to 211 soil samples, the team predicted key soil properties such as organic carbon and particle size (3). Using machine learning (ML) models, both offline and cloud-based methods yielded reliable results, with offline models proving more precise (3). However, cloud computing offered scalability for remote regions, supporting sustainable soil monitoring and conservation strategies in the ARB.

Precision Signal Boost for Non-Invasive Blood-Glucose Tests with Advanced FT-IR and Machine Learning

A study published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy reports major progress in non-invasive glucose monitoring using advanced Fourier transform infrared spectroscopy (FT-IR) (4). Researchers from Linyi University and the University of Science and Technology Beijing enhanced sensitivity with a multi-pass multiple attenuated total reflection (MATR) prism and a quantum cascade laser (QCL), producing clearer glucose spectra. Combined with two-dimensional correlation spectroscopy (2DCS) and machine learning, the system achieved 98.8% accuracy in distinguishing hyperglycemia from normoglycemia (4). This breakthrough brings non-invasive glucose testing closer to clinical adoption, offering a potential alternative to finger-prick blood tests.

SciX 2025 Heads to Covington

The SciX 2025 Conference, hosted by the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS), will be held October 5–10 at the Northern Kentucky Convention Center in Covington, Kentucky (5). This major event highlights cutting-edge research in analytical chemistry, spectroscopy, and instrumentation through oral and poster presentations, short courses, and award ceremonies. Keynote speaker Mike Gold, President of Civil and International Space at Redwire, will deliver a talk, “Unveiling the Unknown: The Pursuit to Understand UAPs” (5). Attendees can also explore the Exhibit Hall, open October 6–8, featuring the latest technologies. SciX fosters networking, career development, and cross-industry collaboration.

References

1. Wetzel, W. Exploring the Key Drivers of the Opposition Surge Effect in Astronomy. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/exploring-the-key-drivers-of-the-opposition-surge-effect-in-astronomy (accessed 2025-09-18).
2. Wang, H.; Wang, H.; Shabab, S.; et al. Spectroscopic Investigation of Charge Transfer Interaction Between Five Antibiotics Depending on Density Functional Theory. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/spectroscopic-investigation-of-charge-transfer-interaction-between-five-antibiotics-depending-on-density-functional-theory (accessed 2025-09-18).
3. Wetzel, W. Using Reflectance Spectroscopy and Cloud Computing in Analyzing Soil. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/using-reflectance-spectroscopy-and-cloud-computing-in-analyzing-soil (accessed 2025-09-18).
4. Workman, Jr., J. Precision Signal Boost for Non-Invasive Blood-Glucose Tests with Advanced FT-IR and Machine Learning. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/precision-signal-boost-for-non-invasive-blood-glucose-tests-with-advanced-ft-ir-and-machine-learning (accessed 2025-09-18).
5. Wetzel, W. SciX 2025 Heads to Covington. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/scix-2025-heads-to-covington (accessed 2025-09-18).