Amperometric Method And Apparatus For Measurement Of Soft Particles In Liquids By Analyzing The Adhesion Of These Particles To An Electrode

摘要

Method and apparatus for measurement and analysis of soft particles in liquids in the size range 1-500 μm represented by vesicles and living cells, liposomes and blood cells in particular, but also to diluted dispersions of oil droplets and other confined microparticles in liquids. The method is based on amperometric detection and analysis of single events of particle adhesion in raw samples, or after the concentration adjustment, by means of permanent record of time series of stochastic electrical signals in the real time. The detected new class of electrical signals is generated by adhesion causing the deformation, rupture and spreading of soft particles at mercury electrode in air saturated liquids. Information stored in one current pulse signal is: particle size, adhesion properties and electrode surface area occupied by the spread particle, which is characteristic for each class of particles. The current pulses, appear at irregular intervals due to the inherently stochastic nature of the I particle encounter with the electrode. The total pulse counts (N) recorded for a: fixed time interval (e.g. 100 seconds) is the measure of particle concentration; (C/particles L⁻¹) in the analyzed suspension. The pulse heights (H/μA) are proportional to the particle sizes. Distribution of pulse heights for the fixed time interval (e.g. 100 seconds) represents a relative size distribution (P). Information stored in the time series of the signals is: concentration of soft microparticles in the suspension (C) and the relative size distribution of soft microparticles (P).