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This curated selection of articles highlights recent advancements in microplastics and nanoplastics and soil analysis.

This is Chemometrics in Spectroscopy Column Number 251. In Column Number 250, we left you with a puzzle. We had just shown that a little-known piece of two-hundred-year-old mathematics, Lagrange's method of undetermined multipliers, could force an MLR calibration to ignore one particular, carefully chosen direction of repack-induced spectral change. It worked, but it only handled one direction at a time, and we admitted we had no idea whether the trick could be extended to PCR or PLS. That bothered us. So in this installment we go looking for the more general version of the idea, and we find it sitting in some very good recent work by Neal Gallagher and Nathanial Watson on what they call clutter suppression (a framework built for a completely different problem, target detection in hyperspectral imaging, that turns out to fit ours almost perfectly). Put the two together and you get an algorithm that whitens the calibration spectra with a clutter covariance matrix estimated from repack replicates, then hands the whitened data to the same Lagrangian machine we built last time. The payoff: the correction now generalizes to several, non-proportional directions of diffuse-reflection variability at once, and, because it is just a preprocessing step, it works ahead of PLS and PCR as well as MLR, which finally answers the question we could not answer before. This approach may very well be an answer to repack variation in repeated solid or slurry sample measurements using diffuse reflection. In this column we change gears with our writing tone and format by taking a "chemometry" approach, rather than a strict tutorial one. In future columns we hope to "unpack" this information in our more typical extended and tutorial manner. Let's explore solving this repack variation problem together.

This dynamic video explores some of the latest advancements in molecular spectroscopy.

Top content published this week include a new digital e-book that explores the role of spectroscopy in cultural heritage analysis and more.

A handheld infrared (IR) scanner paired with an artificial neural network (ANN) can identify human versus animal bone with over 96% accuracy.

Fourier-transform infrared spectroscopy, a technique built on a scanning mirror invented before the moon landing, is quietly being rebuilt from the ground up. Light combs, photothermal probes, and chip-scale photonics are pushing infrared analysis past resolution and speed limits that stood for six decades.

The 29th International Conference on Raman Spectroscopy (ICORS 2026) is set to have a gala dinner cruise for conference attendees to enjoy.

X-ray fluorescence (XRF) spectroscopy has been an important method in the study Stonehenge.

Sapienza Università di Roma team reports near-infrared (NIR) techniques that identify and quantify cocaine and cutting agents through sealed police evidence bags, addressing safety and chain-of-custody concerns in forensic laboratories.

In this preview of the upcoming American Chemical Society (ACS) Fall 2026 Meeting, we sat down with Pavithraa “Pavi” Sundararajan, a postdoctoral fellow at NASA Ames Research Center, talks about her career journey and what inspired her to become an astrochemist.

A forensic case study using FT-IR, portable Raman spectroscopy, and SEM-EDS to differentiate three-layer automotive coatings from a hit-and-run accident, demonstrating that combining complementary spectroscopic and elemental techniques improves the accuracy of paint evidence identification.

The deadline to submit nominations for the 2027 Coblentz Award, presented annually to an outstanding young molecular spectroscopist under the age of 40, has been extended to August 31, 2026.

In this preview of the upcoming American Chemical Society (ACS) Fall 2026 Meeting, we sat down with Pavithraa “Pavi” Sundararajan, a postdoctoral fellow at NASA Ames Research Center, to ask her about what she is looking forward to at the conference.