What specific chemical tests did the Netherlands Forensic Institute use to date the diary inks and papers?
Executive summary
Publicly available material does not identify any specific chemical assays that the Netherlands Forensic Institute (NFI) used to date the diary inks and papers in the matter implied by the question; the NFI’s website confirms broad capabilities in trace and forensic chemistry but does not list case‑level analytical methods for that diary [1]. In the absence of a direct NFI disclosure, the laboratory techniques commonly used to date inks and papers—documented in forensic literature and government research—provide the best basis to infer which methods could plausibly have been applied, and those methods carry important limitations that courts and journalists should not gloss over [2] [3].
1. What the NFI says it can do (but not what it did)
The NFI presents itself as a national forensic laboratory with growing ability to analyse minimal and complex trace evidence, including partnerships with universities for advanced techniques, but the site does not publish a case‑by‑case list of chemical tests applied to specific diaries or documents, so there is no public confirmation that the NFI used any particular ink‑ or paper‑dating assay in this instance [1].
2. Common non‑destructive screening first: light and spectral inspection
Forensic practice starts with non‑destructive optical screening—visible, ultraviolet and infrared examinations—to reveal fading, hidden writings, spectral differences and substrate fluorescence before any sample removal; authoritative overviews and textbooks stress that UV/IR optical methods are routine first steps because they preserve evidence and can reveal which areas merit chemical testing [4] [5].
3. Chemical separation of dyes: TLC and liquid chromatography
When chemical analysis is needed, thin‑layer chromatography (TLC) and various forms of liquid chromatography (notably HPLC) are standard to separate and identify dye components in inks; forensic reviews and manuals cite TLC and HPLC as principal methods for distinguishing inks and building comparative databases that help estimate relative ages and identify manufacturers [2] [4] [5].
4. Mass spectrometry and GC–MS for volatile and molecular markers
Gas chromatography–mass spectrometry (GC–MS) and other mass spectrometric approaches are used to detect volatile solvents, additives and polymer degradation products in inks and paper coatings; peer‑reviewed overviews list GC–MS and high‑resolution MS as tools for profiling ink chemistry that can change with age and thus contribute to dating assessments [2] [6].
5. Elemental and laser methods: LA‑ICP‑MS, LIBS, XPS
Elemental profiling techniques such as laser ablation inductively coupled plasma mass spectrometry (LA‑ICP‑MS), laser‑induced breakdown spectroscopy (LIBS) and X‑ray photoelectron spectroscopy (XPS) are increasingly employed to map elemental composition of inks and papers and to discriminate sources—NIJ‑funded research highlights LIBS and LA‑ICP‑MS for rapid elemental analysis, while recent studies demonstrate XPS chemical imaging for ink differentiation [7] [8].
6. Dating is inferential, often destructive, and constrained by limits
All chemical dating approaches are inferential: inks and papers are dated by comparing known manufacturing markers, solvent loss, dye degradation or elemental fingerprints against reference databases, and many definitive assays require removing micro‑samples—making them destructive—while accuracy depends on up‑to‑date reference material and understanding of storage and environmental effects [3] [9] [4]. Forensic literature repeatedly warns that absolute calendar dating of ink is rarely possible; instead, experts provide relative ages or exclude possibilities [2] [4].
7. What can and cannot be concluded about the NFI’s specific tests
Because neither the NFI public site nor the supplied reporting lists the precise chemical assays the NFI performed on the diary in question, it is not possible to state with evidence which exact tests were used; one can only say the institute has the institutional capability to apply any of the methods cited above and that standard practice would begin with non‑destructive optical screening and then move to chromatographic, spectrometric or laser elemental methods as required [1] [2] [4]. Readers should treat press summaries that claim a single definitive chemical “date” without method disclosure with skepticism, and seek the lab report or expert testimony that specifies which techniques and reference datasets were used.