Microwave dielectrometer application to antibiotic concentration control in water solution

Abstract

Subject and Purpose. This study focuses on the original waveguide-differential dielectrometer designed for complex permittivity measurements of high-loss liquids in the microwave range towards the determination of pharmaceutical ingredient concentrations in water solutions at room temperature. The suitability of the device and effectiveness of the dielectrometry method are tested on such pharmaceutical ingredients as lincomycin and levofloxacin over a wide range of concentrations. Methods and Methodology. The main idea of the method consists in that the complex propagation coefficients of the HE11 wave are obtained from the amplitude and phase shift differences acquired by the wave after it has passed through the two measuring cells of the waveguide-differential dielectrometer. Results. We have shown that the proposed dielectometry method allows a real-time determination of pharmaceutical ingredient concentrations in water solution by measuring the wave attenuation and phase shift differences. We have found that unless concentrations of pharmaceutical ingredients are low, few free water molecules in water solution are bound to the pharmaceutical ingredients. The number of free water molecules in solution decreases as the concentration of pharmaceutical ingredients rises. Conclusion. The current study confirms that the dielectometry method and the device developed provide effective determination of pharmaceutical ingredient concentrations in water solutions.

Monitoring of the Enzymatic Reactions Course by Differential Microwave Dielectrometry Method in Real Time

“…We used a differential microwave dielectrometer (Fig. 1, a) for the study of the enzymatic reaction course that was previously used for the measuring of the high-loss liquids like water solutions [16][17][18][19]. In the dielectrometer manufacturing, we used the generator in the microwave frequency range, where the frequency dispersion of the real and imaginary CP parts of water is observed.…”

“…Open-ended coaxial Liquids and From milliliters 0.05÷0.1 0.01÷50 GHz probe from Keysight [11] conformable solids to microliters for relative comparisons between different materials [16][17][18][19]. When using the resonator techniques, in particular, the microfluidic sensor [20,21], the sensitivity of the CP determination is limited for a liquid with high CP.…”

“…for the first time, to use the microwave differential microwave dielectrometry method for the monitoring of the enzymatic hydrolysis of proteins without the interrupting of the reaction course. For measurements, we used the microwave dielectrometer earlier developed by our scientific team and tested by numerous comparisons with other results described in our papers [16][17][18][19]. The biologically significant reactions of hydrolysis of the human immunoglobulin G (IgG) and human serum albumin (HSA) proteins by enzyme trypsin were selected as the reactions to be examined in the current study.…”