The article describes a comprehensive mass spectrometric approach to the study of surfaces of structural materials. The combined use of thermal desorption mass spectrometry, gas and liquid chromatography, and laser desorption/ionization mass spectrometry (LDI) to provide information about the surface and surface layers of materials is proposed. The suggested method allows one to determine the thermodynamic characteristics of compounds and surface contaminants adsorbed on surfaces, as well as surface layers, to determine the composition of volatile and non-volatile contaminants on the surface, and to determine the nature of the distribution over the surface of these compounds. The method allows to obtain the most complete information about the surface condition and can be used to predict the life of structural materials.

A combination of theoretical and experimental approaches was applied to determine the chromatographic rules of isomeric compounds’ behavior for preliminary identification. In gas chromatography-mass spectrometry (GC-MS), identification is performed by spectra matching, however, difficulties arise with isomeric compounds, which cannot be distinguished from each other without additional information. The thermodynamic characteristics of the adsorption of symmetric and asymmetric isomers of chlorophenylphenols, dimethoxybiphenyls, tri- and tetrachlorobiphenyls were determined using molecular statistical calculations. By-products in the chlorination of 4-hydroxybiphenyl were identified: 4-hydroxy-2,3′- and 3,2′-dichlorobiphenyls, 4-hydroxy-3,5,2′- and 2,3,6-trichlorobiphenyls. A developed theoretical approach was applied to predict the retention order of tri- and tetra-chlorobiphenyls. The GC-MS data and molecular statistical calculations made it possible to determine the main products of methoxybenzene dimerization as well as identify impurities. Thermodynamic parameters were received to describe the unusual retention behavior of epimers in reversed-phase high-performance liquid chromatography. Molecular descriptors were calculated to determine correlation with retention of both structural isomers and epimers. Descriptor combining surface area and partial charge information turned out to be useful in evaluating retention order for isomers.

Ethanol extraction was employed to isolate a range of compounds from waste products derived from coconut fiber production (coconut dust) in Ben Tre, Vietnam. Phytochemical screening confirmed the presence of flavonoids, tannins, polyphenols, saponins, alkaloids, flobatannins, and anthraquinones among the extracted substances. FT-IR spectroscopy analysis supported the identification of oxygen and nitrogen atoms within functional groups (e.g., O–H, N–H, C–O) and aromatic rings, characteristic of typical corrosion inhibitors. Mass spectrometry investigations indicated that when St3 steel was exposed to an alkaline solution lacking chlorides, a passive film composed of FeOOH formed on the surface. However, upon the addition of NaCl at a concentration of 1.00 mol/dm3, FeCl, FeCl2Cl–, and FeCl3Cl– compounds were detected across the analyzed surface, while peaks corresponding to FeOO– were absent. Remarkably, areas with the highest concentration of particles corresponded to regions exhibiting visible corrosion damage under magnification. The addition of 2.00 g/dm3 of coconut dust extract to the chloride solution prevents the formation of Fe and Cl compounds on the steel surface. Consequently, only peaks characteristic of FeOO– and organic fragments containing oxygen atoms from the extract were observed. Based on these results, it can be assumed that coconut dust extract has the potential to inhibit local (pitting) corrosion of low-carbon steel (St3) when exposed to aqueous alkaline solutions simulating concrete pore liquid containing chlorides. The addition of 2.00 g/dm3 of the extract has been shown to prevent pitting formation at a chloride concentration of 1.00 mol/dm3. Conversely, in the absence of the extract, visible local corrosion damage was observed upon magnification. These findings provide a basis for further exploration of the protective properties of coconut dust extract as an environment-friendly corrosion inhibitor for mild steel in concrete environments containing chlorides.

Thin-layer chromatography and matrix-assisted desorption/ionization are used in this work to analyze and to separate monosubstituted and disubstituted nitrobenzoic acids. Parameters of chromatographic process were calculated due to the possibility of visualization of the mass spectrometric method. The data indicate that the mobility coefficients for meta-nitrobenzoic and 3,5-dinitrobenzoic acids differ by approximately two times, and the separation factor is 0.67. It was found that the thickness of a stationary phase (silica gel) of a factory plate for thin-layer chromatography should be decreased to increase the sensitivity of the analysis. It is recommended, therefore, to mechanically remove a small layer of silica gel before starting the analysis. Silica gel acts as a matrix during mass spectroscopic analysis.

This article presents results on the application of mass spectroscopy with a source based on matrix-activated or surface-activated laser desorption/ionization (MALDI/SALDI) for the detection of chlorine on the surface of reinforcing steels after exposure to an environment simulating chloride contaminated concrete pore solution. Due to their informativity, rapidity and reliability, the MALDI/SALDI methods allow to perform the identification of contaminants, as well as the determination of corrosive products upon contact of materials with the environment. It was shown that the mass spectrum includes compounds that can be referred to organic impurities introduced on the sample. It was found that the largest peaks belong to iron hydroxide clusters in the +2 oxidation state. This fact reliably confirms the presence of corrosion at the investigated point. During ionization, various cluster ions with chlorine are formed. Two-dimensional distribution diagrams of [FeCl3](-) and [FeCl3 center dot Fe(OH)(2)](-) particles were constructed for monitoring corrosion traces on the surface under study. The obtained results show the investigated surface heterogeneity, which is associated with active corrosion processes and acting features of the aggressive environment. Traces of adsorption of chlorine, which is a potential corrosion activator, were found on the steel surface, and its localization was shown. The distribution of the chloride ion over the studied surface is characterized by a relatively uniform distribution. The Cl- distribution diagram also shows areas that differ in concentration by several times, which characterize the next formation of corrosion pits. Thus, in this work, the possibilities of using the MALDI/SALDI methods for assessing the distribution of chlorine and detecting corrosion on steel surfaces at an early stage are shown.