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Rationale The effort to make fake documents look real leads to the use of crickets and beverages to produce artificially aged papers, as land titles, based on yellowing caused by the use of these methods. An old practice in Brazil, called “cricketing”, has led to the misappropriation of Brazilian land using these documents. We propose a rapid, simple, instantaneous and non‐destructive method to identify artificially aged papers by easy ambient sonic‐spray ionization mass spectrometry (EASI‐MS) analysis. Methods Three typical aging procedures were used to obtain artificially aged papers using coffee, cola drink, and crickets, with the papers being analyzed by EASI‐MS. Multivariate statistical analyses were performed on the data to find the sample groups and to study the most relevant ions of each ageing procedure. High‐resolution MS (HRMS) was used to obtain the exact masses and attribute formulae to relevant ions present in the samples. Results The combination of EASI‐MS and multivariate statistical analyses allowed us to identify the most relevant ions to classify the adulteration of documents and HRMS identified most of these relevant ions. TMS fingerprinting in combination with multivariate analysis also demonstrated that this approach can qualitatively differentiate all the examined paper samples. Conclusions We developed a cheap, fast and easy method that can help to elucidate counterfeit documents that have been artificially aged, helping to identify chemical additives and one that can be used in forensic laboratories.

The ionizable molecular composition of 36 lacustrine oil samples and 29 marine oil samples from different off-shore Brazilian basins have been screened by ultrahigh-resolution and accuracy Fourier transform ion cyclotron resonance mass spectrometry with electrospray ionization in the negative-ion mode [ESI(−)-FT-ICR MS]. The negative mode has been demonstrated successfully to characterize source rock because it favors the detection of heteroatomic compounds such as nitrogen-, sulfur-, and oxygen-containing (NSO), which reveal information about geochemical environmental. ESI(−)-FT-ICR MS data was processed with a new approach that unifies information from the chemometrics tool and petroleomics conventional data processing. Novel diagrams were proposed that use variable important to projection (VIP), such as molecular formula obtained, via partial leastsquare discriminant analysis (PLS-DA) to plot in diagrams, such as those that display double bond equivalence (DBE) versus number carbon atom (NCA) and H/C ratio versus molecular mass (MM) trends. This new approach is advantageous since it is able to verify and compare all samples at once, obtaining more selective variables, such as molecular formula, and with more confidence because the figures of merit are acquired by statistical tests from PLS-DA, whereas it also provides the usual information from petroleomics tools such DBE, NCA, H/C ratio, MM, and molecular classes. This new approach revealed significant differences in the molecular distribution of heteroatomic components for N-containing and O-containing molecules (N class and O class) allowing a clear separation of all samples in two groups of marine or lacustrine crude oils.

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