Highlights from What’s Nu August 2026

Analytical chemistry and spectroscopy are seeing rapid advancements thanks to technological innovation. The hardware that comprised older instruments is now being updated to improve the speed and precision of modern spectroscopic instrumentation. Because of these changes, new innovations, including dual-comb spectroscopy, forensic clear-coat analysis, and high-performance inductively coupled plasma–mass spectrometry (ICP-MS) method transfers—are rewriting the rules of molecular and elemental identification.

In this Q&A overview, we recap the content in Spectroscopy’s August “What’s Nu” newsletter, highlighting fun facts about Beer’s Law and advancements in trace analysis for forensic and pharmaceutical laboratories.

Fourier-transform infrared (FT-IR) spectroscopy has relied on a moving mirror for 60 years. Is this classic interferometer design becoming obsolete?

The classic interferometer still has value in modern analytical spectroscopy, but there are current challenges that the technology is facing. For example, FT-IR spectroscopy historically relied on a mechanical sliding mirror inside a Michelson interferometer to generate an interferogram.¹ Today, dual-comb spectroscopy is eliminating this mechanical movement. By mixing two coherent frequency combs from quantum cascade mid-infrared (MIR) lasers, dual-comb systems generate radio-frequency interferograms without mechanical scanning.¹

This shifts spectral resolution down to the megahertz level. This is an improvement of four orders of magnitude and cuts acquisition times to under a millisecond.¹ Although classic benchtop instruments remain the most cost-effective choice for routine bulk analysis, dual-comb spectroscopy has opened up new frontiers in tracking transient reaction intermediates, detecting gas leaks, and monitoring combustion in real time.¹

Spatial resolution has historically been a major bottleneck in infrared microscopy. How are designers breaking this “diffraction barrier”?

Conventional IR microscopy is limited by MIR diffraction. As a result, it caps spatial resolution at several micrometers.¹ Two techniques improve spatial resolution: optical photothermal infrared (O-PTIR) spectroscopy and atomic force microscopy–infrared (AFM-IR) spectroscopy.

O-PTIR spectroscopy uses a shorter visible wavelength to deliver a 30-fold improvement, achieving a ~450 nm spot size and simultaneous co-localized Raman and IR spectra without complex sample preparation.¹ This pairing is highly valuable for mapping protein aggregates inside individual cells and identifying microplastics.¹

AFM-IR spectroscopy uses an AFM cantilever’s sharp tip as the absorption sensor.¹ Localized thermal expansion launches a cantilever oscillation, mapping chemical features down to 10 nanometers.¹

In forensic science, how does integrating these spectroscopic tools help solve high-stakes investigations?

Spectroscopic tools are regularly used in forensic science today, and crime scene investigations normally involve using several techniques to reduce error. This strategy is especially integral for investigating hit-and-run accidents.² Out of 16 paint subcategories under national standards, roughly eight are widely used in automotive coatings.² Recently, a team of researchers demonstrated that a comprehensive approach helps differentiate these complex polymer systems. In a recent case study, investigators analyzed three-layered silver paint fragments under 50× magnification, performing contamination-controlled microdissection to isolate each stratum.²

The researchers found that FT-IR spectroscopy effectively differentiated the acrylic amino first layer from the alkyd amino second layer.² Acrylic amino was identified by combining melamine triazine bands (~1552/815 cm⁻¹) with acrylic C=O stretching at 1731 cm⁻¹.² Alkyd amino exhibited distinguishing alkyd resin absorptions at 1262, 1122, 743, and 761 cm⁻¹.²

In the third (white) layer, the scene sample and “Suspect 1” contained epoxy polyester paint with TiO₂ and BaSO₄, while “Suspect 2” had alkyd amino paint, excluding it.² This exclusion was cross-verified using portable Raman spectroscopy (800–1000 cm⁻¹ peak shapes) and SEM-EDS (magnesium was present in the scene and Suspect 1 but absent in Suspect 2).²

Shifting to trace metals, what hurdles do laboratories face when transferring ICP-MS methods for difficult analytes like palladium?

Transferring ICP-MS methods is a complicated process. Some of the obstacles analysts face when doing this include low recovery and memory effects, especially when samples require robust digestion.³ As an example, the authors of a recent study showed that during a transfer from an Agilent 7700/Anton Paar system to an Agilent 7900/MARS system, palladium recoveries dropped to 40–50%.³

How were these palladium recovery and memory issues resolved?

The laboratory resolved this by upgrading to MARS Easy Prep high-performance vessels, which operate safely at higher temperatures and pressures. Raising the microwave digestion temperature to 230 °C dramatically improved recovery.³ Additionally, adding perchloric acid (HClO₄) to the nitric/hydrochloric acid mixture provided the strong oxidizing conditions needed to digest the matrix.³ In contrast, pre-digestion sonication was found to offer no improvement and increased sample loss risk.³ Finally, increasing the rinse time to 250 seconds eliminated palladium memory effects, yielding consistent 98–100% recoveries with no carryover.³

And finally, what did the “What’s Nu” newsletter highlight about Beer’s Law?

We highlighted in “What’s Nu” how the equation that most spectroscopists associate with Beer’s Law (A = εbc), which is the cornerstone of quantitative spectroscopy, doesn’t actually appear in August Beer’s 1852 paper.⁴ Beer studied how absorption depends on concentration, but the pathlength dependence traces back to Bouguer and Lambert’s earlier work in photometry, which Beer himself credited in his 1854 book.^4–6 Notably, his 1853 textbook on optics doesn’t develop the concentration-absorption law either.⁶ The modern A = εbc formula is a later synthesis of these separate contributions, not something any single scientist wrote down.⁷ Even IUPAC’s official definition reflects this composite history.⁸ The main takeaway is that today’s fundamental equations often have far messier, more collaborative origins than textbooks suggest.

References

1. Workman, Jr., J. Is the Moving Mirror Obsolete? Six Innovations Redefining FT-IR Instrumentation. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/is-the-moving-mirror-obsolete-six-innovations-redefining-ft-ir-instrumentation (accessed August 31, 2026).
2. Ge, Y.; Lv, J. Forensic Differentiation of Automotive Coatings with Multiple Spectroscopic Methods: Comprehensive Spectral Information Analysis for More Accurate Identification. Spectrosc. Suppl. 2026, 41 (wp8). DOI: 10.56530/spectroscopy.tp2087o9
3. Izmer, A. Resolving Poor Recovery and Memory Effects in Trace Metal Analysis by Inductively Coupled Plasma Mass Spectrometry (ICP-MS): A Method Transfer Case Study. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/resolving-poor-recovery-memory-effects-trace-metal-analysis-icp-ms-case-study (accessed August 31, 2026).
4. Beer, A. Bestimmung der Absorption des rothen Lichts in farbigen Flüssigkeiten. Ann. Phys. Chem. 1852, 162 (5), 78–88. DOI: 10.1002/andp.18521620505.
5. Beer, A. Grundriss des photometrischen Calcüles; Vieweg: Braunschweig, Germany, 1854.
6. Beer, A. Einleitung in die höhere Optik; Vieweg und Sohn: Braunschweig, Germany, 1853. Digital copy at Google Books
7. Mayerhöfer, T. G.; Pahlow, S.; Popp, J. The Bouguer–Beer–Lambert Law: Shining Light on the Obscure. Chem. Phys. Chem. 2020, 21 (18), 2029–2046. DOI: 10.1002/cphc.202000464.
8. International Union of Pure and Applied Chemistry. Beer–Lambert Law. In Compendium of Chemical Terminology, 5th ed.; IUPAC: Research Triangle Park, NC, 2025; Online version 5.0.0. DOI: 10.1351/goldbook.B00626.