Highlights from What’s Nu October 2026

Spectroscopy Magazine’s"What’s Nu" is a play on words combining the Greek letter ν (nu), which is traditionally used in spectroscopy to denote electromagnetic radiation frequency, with "What’s New." This monthly newsletter highlights modern advancements in analytical spectroscopy, illustrating how these measurement techniques are expanding beyond traditional laboratory settings into diverse fields.

In this Q&A, we recap the October edition of “What’s Nu,” which covered topics such as how novel spectroscopic and analytical methods are transforming environmental monitoring, medical treatment, and accessibility in scientific research.

What was the main historical feature that anchored October’s edition of What’s Nu?

In the introduction of the October edition of What’s Nu, Spectroscopy Magazine presented a historical feature tracing the roots of nonlinear spectroscopy back to paper-and-pencil theoretical physics.¹ In her 1931 doctoral thesis at the University of Göttingen, Maria Goeppert-Mayer developed the quantum mechanical theory showing that an atom could absorb two lower-energy photons simultaneously to reach an excited state requiring twice the energy of a single photon.¹ Because two-photon absorption demands extremely high photon densities, her prediction lay unverified for 30 years until the invention of the laser.^1,2 In 1961, Wolfgang Kaiser and C. G. B. Garrett at Bell Labs experimentally confirmed her theory using europium-doped calcium fluoride crystals.² Goeppert-Mayer went on to share the 1963 Nobel Prize in Physics for her later work on the nuclear shell model.³

Today, spectroscopists still honor her legacy through the standard unit for two-photon absorption cross-sections: the Goeppert-Mayer (GM).⁴ Her theoretical insight also underpins two-photon laser scanning fluorescence microscopy, which was demonstrated in 1990 by Denk, Strickler, and Webb for deep 3D tissue imaging, as well as nonlinear vibrational techniques like hyper-Raman, coherent anti-Stokes Raman scattering (CARS), and stimulated Raman scattering (SRS).⁵

How are the 2026 FACSS Innovation Award finalists pushing spectroscopy beyond the traditional laboratory?

What’s Nu also highlighted the four finalists for the FACSS Innovation Award presented at SciX 2026. Each finalist discussed a different technique, but all of them challenged the idea that spectroscopy belongs solely at a laboratory bench with a trained operator and a monitor.⁶

Below, we outline what each finalist discussed:

1. Drone-Borne Volcanic LIBS: Alessandro De Giacomo (University of Bari) deployed a calibration-free laser-induced breakdown spectroscopy (LIBS) sensor on an eight-propeller drone.⁶ By fitting emission lines to an apparent Boltzmann distribution under apparent local thermodynamic equilibrium, the system was designed to self-correct without external standards, quantifying elements in volcanic ash in flight down to about 0.1%.⁶
2. Haptic VR for Blind Scientists: John H. Kalivas (Idaho State University) created a haptic-first virtual reality environment using force-feedback gloves and spatial audio.⁶ In a pilot study, four blind university students used touch and sound cues to judge, from mid-infrared (MIR) spectra, whether new clam samples belonged to an uncontaminated class, correctly overturning a number of the algorithm’s false positives and false negatives.⁶
3. Molecular Memory in Polymers: Dabin Kim (NIST) used polarization-controlled infrared (IR) microscopy to map molecular alignment through shape memory polymer deformation and recovery cycles, suggesting that some residual alignment memory persists after recovery.⁶
4. Nanomedicine for Parkinson's Disease: Salah Oudjertli (Research Center in Industrial Technologies, Algeria) designed an ultrasound-activated graphene–gallium-doped zinc oxide nanotransducer.⁶ The platform combines plasmon-enhanced spectroscopy with targeted blood–brain barrier transport; in transgenic mice, focused ultrasound activation produced a 71.3% reduction in α-synuclein fibril burden and a 4.2-fold improvement in motor coordination.⁶

Why is target analysis alone insufficient for PFAS, and how does sum-parameter analysis solve "The Fluorine Challenge"?

In a recent “Atomic Perspectives” column, Sebastian Kampf, Pia Schünemann, and Björn Meermann of Germany’s Federal Institute for Materials Research and Testing (BAM), together with Carolin Dietze, detail analytical strategies for per- and polyfluoroalkyl substances (PFAS).⁷ With more than 7 million possible individual compounds, traditional target analysis using liquid chromatography–tandem mass spectrometry (LC–MS/MS) can quantify only about 55 PFAS (57 in foodstuffs and 54 in groundwater) because labeled internal standards are scarce.⁷

To close this gap, BAM researchers advocate high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) to measure extractable organic fluorine (EOF) as a sum parameter.⁷ By measuring the absorption of short-lived gallium fluoride (GaF) molecules at 211.248 nm, HR-CS-GFMAS quantifies organically bound fluorine as a whole rather than species by species.⁷ An optimized four-step method refined by Simon et al. reduced the relative standard deviation of response factors across 12 PFAS from 55% to 27%.⁷

The BAM team highlighted three major applications:

1. River Sediment Trends: Analysis of suspended particulate matter samples from German rivers (2005–2020) revealed that while the fraction of EOF explained by known target PFAS decreased, unexplained EOF steadily increased, most likely reflecting a shift from known to unknown PFAS.⁷
2. Plant Bioaccumulation: A study on French bean plants (Phaseolus vulgaris) showed that short-chain PFAS accumulated predominantly in the fruits, whereas long-chain PFAS were mainly retained in the roots.⁷
3. Polymer Leaching: Extraction tests on 12 (non-)fluorinated sealing materials showed measurable fluorine leaching into water in 9 of the 11 samples tested, highlighting environmental concerns when disposed polymers come into contact with rainwater and groundwater.⁷

How is 2D FT-IR spectral imaging revealing the mechanics of knee implant post fractures?

In a SciX 2026 interview, Nancy Pleshko and Petra Baylin (Temple University) discussed their investigation of polyethylene post fractures in posterior-stabilized knee implants. Although post fracture occurs in under 1% of cases, it disrupts joint mechanics and causes instability that requires revision surgery.⁸

While standard studies use 1D line profiles (yielding ~30–60 measurements), Pleshko and Baylin employed 2D FT-IR spectral imaging with a 50 µm sampling interval, acquiring approximately 10,000 to 15,000 spectra per region.⁸ A critical sample preparation step required boiling microtomed sections in n-heptane. Synovial fluid lipids absorbed in vivo contain ester carbonyl groups that overlap the polymer oxidation band; heptane extraction removes these lipids to prevent artificially inflated oxidation readings.⁸

Their 2D maps showed that oxidation peaks at the post’s mid-height, which the researchers attribute to cumulative oxygen diffusion combined with repeated contact from the femoral component in that region.⁸ Modern crosslinking and antioxidant treatments make polyethylene more resistant to oxidation but can also reduce its ductility, while oxidation itself causes subsurface hardening and embrittlement that can lead to delamination.⁸ Because the patient cohort in their study skewed younger and male, the researchers suggested combining modified post designs with tailored implant selection and patient activity guidance.⁸

References

1. Göppert-Mayer, M. Über Elementarakte mit zwei Quantensprüngen. Ann. Phys. 1931, 401 (3), 273–294. https://doi.org/10.1002/andp.19314010303
2. Kaiser, W.; Garrett, C. G. B. Two-Photon Excitation in CaF₂:Eu²⁺. Phys. Rev. Lett. 1961, 7 (6), 229–231. https://doi.org/10.1103/PhysRevLett.7.229
3. The Nobel Prize in Physics 1963. NobelPrize.org. https://www.nobelprize.org/prizes/physics/1963/summary/ (accessed October 23, 2026).
4. Rumi, M.; Perry, J. W. Two-Photon Absorption: An Overview of Measurements and Principles. Adv. Opt. Photonics 2010, 2 (4), 451–518. https://doi.org/10.1364/AOP.2.000451
5. Denk, W.; Strickler, J. H.; Webb, W. W. Two-Photon Laser Scanning Fluorescence Microscopy. Science 1990, 248 (4951), 73–76. https://doi.org/10.1126/science.2321027
6. Workman, J., Jr. Drones, Haptic Gloves, and Sound-Driven Nanomachines: Is Spectroscopy Outgrowing the Laboratory? Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/drones-haptic-gloves-and-sound-driven-nanomachines-is-spectroscopy-outgrowing-the-laboratory- (accessed October 22, 2026).
7. Kampf, S.; Schünemann, P.; Dietze, C.; Meermann, B. Elemental Analytical Methods in the Field of Non-metal Analysis: The Fluorine Challenge. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/elemental-analytical-methods-in-the-field-of-non-metal-analysis-the-fluorine-challenge (accessed October 22, 2026).
8. Pleshko, N.; Baylin, P. A.; Wetzel, W. Mapping Oxidation in Fractured Knee Implant Posts with FT-IR Imaging. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/mapping-oxidation-in-fractured-knee-implant-posts-with-ft-ir-imaging (accessed October 22, 2026).