Abstract:
A method for analysis of a multi-component fluid is provided based on the features of the dynamics of the self-organization processes in drying drops. An electro-acoustic resonator is utilized, with a drop of multi-component fluid placed on one end of the resonator. A shear oscillation is imparting to the resonator along its longitudinal axis. And oscillating electric voltage is placed across the resonator generally perpendicular to the direction of mechanical oscillation. Changes in the electrical conductance corresponding to changes in the acoustical-mechanical impedance can thereby be measured as the drop of multi-component liquid dries. The particular geometry of an amplitude curve includes identifying the spatio-temporal development and phase transitions is used for integral estimation of food authenticity and quality.
Abstract:
A method for measuring changes in the composition of fluids, for medical diagnostics or quality control of fluids, comprising: One) placing a drop of fluid upon a quartz crystal; Two) generating ultrasonic vibrations of a predetermined frequency in the crystal; with the vibrating wave directed into the drop of fluid in a vertical direction relative to the area of the crystal upon which the drop is placed; Three) measuring voltage changes over a bridge circuit connected to the crystal, over a time period during which total or partial evaporation of the liquid occurs; Four) comparing the measurement result to previously obtained results or to predetermined data; Five) detecting changes in the composition of the fluid, from the results. detecting changes in the composition of the fluid, from said results.
Abstract:
The present invention relates to physical chemistry and can be used for a quality test of liquids, in particular, multi-component liquid products, to ascertain the conformity of various process liquids, pharmaceutical preparations, foodstuffs, biological liquids to standard in pharmacology, food processing and chemical industries, and in medical diagnostics. The method of invention enables determining of the mechanical impedance within a drop (1) of test liquid having a specified volume, in the preferred embodiment, 5 mcl, placed on the surface of a piezoelectric resonator (3) of ultrasound frequencies, which provides for excitation of shear modes within drop (1) while it is drying up. The obtained time dependence of the mechanical impedance of drop (1) is used as the information parameter. This information parameter is rather sensitive to the state of the liquid-crystalline structure of multi-component liquids, therefore, comparing the obtained time dependence with the same data for the etalon specimen allows one to assess the composition of a multi-component liquid, test the quality of liquid products, for example, foodstuffs, assess the prospective effectiveness of medical treatment with various medical preparations through analysis of a biological liquid, etc.In the apparatus of invention, the mechanical impedance of test liquid is determined from the disbalance voltage of a bridge circuit (9) comprising a piezoelectric resonator of ultrasound frequencies (3), in preferred embodiments, from the amplitude and/or phase of the disbalance voltage, which ensures high accuracy of measurements.