A short, opinionated round-up of new analytical chemistry papers worth a look. Every note below is written from scratch — follow the link for the authors’ own words.
Ionic strength is a matrix effect — and it cuts both ways
Most discussions of matrix effects assume the signal goes down. This group looked at what dissolved sodium and calcium chloride do to PFAS quantification at concentrations typical of ordinary fresh water, and found effects running from heavy suppression all the way to a tenfold enhancement. Short-chain compounds were affected most strongly, and the direction depended on which cation was present.
The uncomfortable finding is not the size of the effect but what happened to the isotope-labelled internal standard: the analyte and its labelled analogue did not respond in step. Isotope dilution, the technique most laboratories treat as a safety net, did not fully correct the bias.
Why it matters: If your samples vary in ionic strength — and most environmental and clinical samples do — a matrix factor measured on one pooled blank may not describe them. The authors argue for matrix-matched calibration or standard addition, and for reporting the ionic composition of the sample alongside the result.
The derivatisation option most laboratories never consider
Derivatisation is normally something that happens to the sample before injection, with all the cost that brings: reagent excess, extra steps, altered chromatography. This review makes the case for the alternative — reacting the analyte after it has already been separated, or inside the ion source itself, so the separation is left untouched.
The authors’ starting point is the same list of problems that drives most LC-MS troubleshooting: poor ionisation efficiency, unstable analytes, matrix interference. Their argument is that post-column chemistry is well covered for optical detection but thinly documented for MS.
Why it matters: If you have exhausted sample preparation, chromatography and source tuning on a stubborn analyte, this is the lever that is usually still untried. One caveat: despite appearing in a current issue, the paper has been available online since March 2025 — it is a useful reference rather than a new result.
When your sorbent binder can’t take the heat
Commercial SPME blades are built for elution into a solvent, not for thermal desorption — the polymer that holds the sorbent in place degrades before the temperature is high enough to release semivolatile compounds. Rather than accept that limit, this group added four microlitres of octanol to the blade before desorption, which brought the required temperature down to around 100 °C.
The demonstration used four drugs of abuse in saliva, with detection limits reaching the sub-microgram-per-litre range, assessed against selected ICH M10 criteria.
Why it matters: The transferable idea is chemical assistance instead of more heat. Anyone running thermal desorption on a temperature-limited sorbent can borrow the principle, whatever the instrument.
Two open-access papers that settle recurring arguments
A direct comparison of two separation modes applied to the same non-target screening problem. Worth reading if you have ever wondered how much of what your screening method “finds” is determined by the column rather than by the sample.
Protocols compared head to head rather than in isolation. The kind of paper to keep at hand for the next time somebody asks whether precipitation is really good enough.
Why both matter: Method-comparison papers age slowly and are far more citable in a laboratory discussion than a single-method demonstration. Both are free to read.
Also noted
A robust isotope ratio LC–MS/MS workflow for high-throughput metabolic profiling of bacteria — Analytical Chemistry, 8 August 2026. Isotope ratio measurement built for throughput rather than for a showcase experiment.
About this series. Literature Watch collects publications from a set of analytical chemistry journals and adds a short note on why each one might matter in practice. The notes are written independently and do not reproduce any publisher abstract. Selection is a judgement call, not a systematic review — and coverage depends on which journals were reachable when the issue was compiled.
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