Vol 78, No 8 (2023)

A method is developed for determining concentrations in Zeeman electrothermal atomic absorption spectrometry based on the conversion of the transformation function of an atomic absorption spectrometer into a calibration dependence adapted to the matrix of the analyzed sample. The transformation function is expressed as a one-parameter saturation function, which is an integral optical characteristic of the spectrometer, independent of the composition of the analyzed sample. The algorithm of the method includes measurement of the analytical signals of an analyzed sample and a same sample with a known additive of the analyte and calculation of the matrix coefficient and the desired concentration of the analyte in the analyzed sample from these signals. The adaptive calibration method is tested for As, Au, Cd, Cu, Mo, Pd, Pb, Mo, Pd, Pb, Ti, V. The relative systematic error in determining the concentration of an element in the range of measuring the absorbance of atomic vapor does not exceed 10%. The analytical ranges for the elements exceed three orders of magnitude.

A single sensor with a piezoelectric quartz transducer is considered a platform for simulating an “electronic nose” that performs the function of a sensor array. The analytical task was to detect volatile organic compounds, component-by-component, in biosamples at diagnostically relevant concentrations without selecting mixtures or any sample preparation. We confirmed the fundamental possibility of utilizing a single sensor for the separate detection (recognition) of vapors of organic compounds and various functional states of a body during a short contact (60–80 s) with skin, the most representative and constantly performing bioassay. Modifying the electrodes of bulk acoustic wave piezoelectric quartz resonators with 2–4 μg of the nanohydroxyapatite phase is an essential step in solving the problem. The newly calculated adsorption kinetic parameters can be used to detect biomarkers of many diseases with high reliability, including С3–С5 alcohols, ketones, linear and cyclic amines, acids, aldehydes, etc. The hydroxyapatite sensor can detect molecules pointing to problems with many organs, and any abnormalities in the functioning of the nervous and cardiovascular systems. It can also measure the body’s responses and compensatory mechanisms in relation to stress, hunger, and fatigue. The sensor has a potential as a simple diagnostic and monitoring tool for point-of-care diagnostics of both adults and children.

The technology is based on recording the focal activity (FA) of the olfactory bulb (OB) of rats upon the exposure rats to trinitrotoluene (TNT) vapors in the concentration 4.7 × 10–15 g/cm3, separately and in a mixture with saturated vapors of a complex interference composed of spices. The focal activity of the rat olfactory bulb was recorded using an array of 16 special electrodes implanted in the dorsal part of the rat olfactory bulb. The setup contained a box with a rat, sources of vapors (odorants), a multichannel digital system for recording electrical signals from an electrode array, and software performing algorithms for recognizing and classifying odorants presented to the rat. One source of TNT vapors was a device for batch volumetric preparation with a concentration of about 10–15 g/cm3, and another source was a source with a concentration of 4.7 × 10–15 g/cm3 in an air flow presented to rats. Data from 25 tests showed a 100% probability of detecting TNT vapors of the specified concentrations in pure air and also in the presence of a complex odor interference in the form of vapors from a mixture of red pepper, coriander, tobacco, etc., which, as a rule, mask the smell of TNT for animals.The technology is based on recording the focal activity (FA) of the olfactory bulb (OB) of rats upon the exposure rats to trinitrotoluene (TNT) vapors in the concentration 4.7 × 10–15 g/cm3, separately and in a mixture with saturated vapors of a complex interference composed of spices. The focal activity of the rat olfactory bulb was recorded using an array of 16 special electrodes implanted in the dorsal part of the rat olfactory bulb. The setup contained a box with a rat, sources of vapors (odorants), a multichannel digital system for recording electrical signals from an electrode array, and software performing algorithms for recognizing and classifying odorants presented to the rat. One source of TNT vapors was a device for batch volumetric preparation with a concentration of about 10–15 g/cm3, and another source was a source with a concentration of 4.7 × 10–15 g/cm3 in an air flow presented to rats. Data from 25 tests showed a 100% probability of detecting TNT vapors of the specified concentrations in pure air and also in the presence of a complex odor interference in the form of vapors from a mixture of red pepper, coriander, tobacco, etc., which, as a rule, mask the smell of TNT for animals.