This invention relates to the field of microfluidic flow cytometry and more generally microfluidic techniques for analysis of particulate-containing fluids. It deals with the improvements to such technologies in order to identify subsets of particles or sub-populations of cells that differ in their properties, and, if necessary, separate the said identified sub-populations of cells, e.g. sex of semen cells, alive cells from the dead ones, cancerous cells from the healthy ones, subsets of viruses, bacteria or subsets of particles. This invention disclosure deals with the apparatus and the method for detection of cells or particles based on measurements of complex AC impedance between electrodes across the flow of fluid containing such cells or particles.