CVD‑engineered silver nanoparticle substrates for matrix‑free LDI‑MS analysis of diesel fuel components

Abstract Rapid screening of diesel‑fuel composition remains challenging because the hydrocarbon matrix is chemically complex and conventional chromatographic workflows are labor‑intensive. Here, we systematically examined how chemical vapor deposition (CVD) parameters influence the morphology and analytical performance of silver nanoparticle (AgNPs) substrates for nanostructure‑assisted laser desorption/ionization mass spectrometry of diesel‑fuel components. Stainless‑steel plates were coated with AgNPs layers using a volatile silver precursor while varying deposition time, precursor‑evaporation temperature (T s ), deposition temperature (T d ), and argon flow rate. The resulting surfaces were characterized by SEM and AFM, and their performance was evaluated by LDI‑MS for a certified diesel standard and three real diesel samples, in parallel with conventional MALDI‑MS using DHB and HCCA matrices. Within the investigated dataset, substrates prepared at T s = 240 °C, T d = 290 °C, 60 min, and intermediate Ar flow formed continuous fine‑grained AgNPs films that were among the best‑performing surfaces in terms of signal richness and spectral coverage. For the real diesel samples analyzed here, AgNPs‑assisted NALDI generally produced cleaner, analyte‑centered spectra than MALDI‑MS, whereas for the diesel reference standard the MALDI datasets contained a broader overall set of detected m/z features. These findings support CVD‑prepared AgNPs substrates as promising matrix‑free platforms for rapid diesel profiling, although the present conclusions should be regarded as exploratory until validated with independently prepared replicate substrates.