The presence of correlation dependences between the type of motor oil and its refractometric and electrophysical characteristics (refractive index, specific resistance and dielectric constant) is experimentally shown. Methods for determining the type of engine oil are proposed, based on the measurement of these characteristics, as well as prototypes of portable measuring devices that implement these methods. Impedance spectroscopy was used to determine the resistivity and dielectric constant, and a device based on the effect of surface plasmon resonance was used to determine the refractive index. It is shown that the accuracy of identification of the type of motor oil increases significantly with simultaneous consideration of all above physical characteristics. It is shown that this complex method can most accurately detect, on the one hand, purely synthetic motor oils, on the other hand, oils with a mineral component (semi-synthetic and mineral). The results of the studies can be used to identify the type of motor oil as well as to detect forgery.

The authors propose a method for determination of the electro-physical characteristics of electrical insulating liquids on the example of different types of gasoline. The method is based on the spectral impedance measurements of a capacitor electrochemical cell filled with the liquid under study. The application of sinusoidal test voltage in the frequency range of 0,1—10 Hz provides more accurate measurements in comparison with known traditional methods. A portable device for measuring total electrical resistance (impedance) of dielectric liquids was designed and constructed. An approach for express estimation of octane number of automobile gasoline using spectroimpedance measurements and statistical multi variation methods of data analysis has been proposed and tested.

This work is devoted to the study of sensory properties of nanocomposites of electrically conductive polymers towards a number of phosphorus and organochlorine volatile compounds that are simulators of toxic gaseous substances, as well as nitroaromatic simulators of explosive organic substances. Gas sensitivity measurements were performed using an array of chemoresistive sensor microelectrodes covered with thin layers of these nanocomposites. The relative responses was at the level of 4–5%, the detection threshold depending on the type of analyzed toxic substances was from 10 to 100 ppm, the response rate was about 1 minute. The possibility of qualitative identification of toxic and explosive substances in a wide range of concentrations using the methods of statistical analysis of data from the sensory array has been demonstrated.