mini-Ni : A small GC-MS database of nitrogen-containing compounds

mini-Ni is a small database of electron ionization mass spectra and retention indices for nitrogen-containing compounds, mainly aromatic heterocycles.Full details of this database, reagents, GC-MS experimental conditions, etc. are contained in the corresponding published paper (please cite it when using this database!): Sholokhova AY, Borovikova SA, Kosyakov DS, Matyushin DD. A GC-MS Database of Nitrogen-Rich Volatile Compounds. Toxics. 2025 Nov 16;13(11):986. https://doi.org/10.3390/toxics13110986Gas chromatography-mass spectrometry (GC-MS) is a very important method of chemical analysis. Identification is performed using a library search of the mass spectrum in a mass spectral database, and retention index information is also used. Nitrogen-containing small molecules with a high content of nitrogen (Ni means i nitrogen atoms), such as derivatives of triazoles, pyrazoles, imidazoles, diazines, etc., including those containing -CN and -NH2 groups, are an important class of analytes, including priority pollutants. Unfortunately, such compounds are insufficiently represented in the available GC-MS databases, and the databases also contain erroneous entries. This database partially fills this gap.All data (and further notes) are provided in an XLSX file. The other three files also contain mass spectra and retention indices, in formats suitable for import into NIST MS Search and other software. To import the SDF file into NIST MS Search, use the Lib2NIST utility.Electron ionization mass spectra and retention indices (5%-phenylpolydimethylsiloxane and polyethylene glycol) for 104 molecules are provided. For 72 molecules, retention indices are given for three different heating rates (temperature programming mode). The following chromatographic conditions were used for these molecules:Non-polar stationary phase:Column: 5%-phenyl-methylpolysiloxane, HP-5MS, 30m х 0.25mm х 0.50µm, Agilent; starting temperature 40 °C; helium flow rate 0.84 mL/min;Polar stationary phase:Column: polyethylene glycol, HP-INNOWax, 30m х 0.25mm х 0.25µm, Agilent; starting temperature 40 °C; helium flow rate 1.01 mL/min;The analyte solution in methanol (up to 10 analytes in one batch, concentration of each ~0.1 mg/mL) was injected using split injection mode (0.5 μL, 1:20). In some cases, the concentration was increased until high-quality mass spectra of sufficient intensity were obtained.Some of the retention index data was taken from the following source: Karnaeva A. E., Sholokhova A. Y. Validation of the identification reliability of known and assumed UDMH transformation products using gas chromatographic retention indices and machine learning //Chemosphere. – 2024. – V. 362. – P. 142679. https://doi.org/10.26434/chemrxiv-2024-mfbd6 (CC BY 4.0 license)All mass spectra were recorded using a Shimadzu GCMS-TQ8040 (quadrupole mass analyzer, 70 eV electron ionization mode). All mass spectra and retention indices were obtained using pure standards.