Abstract: A biological component concentration fluid assembly includes magnetizing microparticles that are surface-activated to bind with (or are bound to) a biological component; a multi-fluid density gradient column with a first fluid layer, a second fluid layer, and a third fluid layer; and a magnet to attract and draw the magnetizing microparticles from the first fluid layer, through the second fluid layer, and into the third fluid layer. The first fluid layer has a first fluid density, and a second fluid layer has a second fluid density that is greater than the first fluid density, and is positioned beneath the first fluid layer. A third fluid layer has a third fluid density that is greater than the second fluid density and is positioned beneath the second fluid layer. The second and third fluid layers in this example are formulated to interact with the surface of the magnetizing microparticles.

Abstract: An example device includes a processor to connect to an electrode disposed within a microfluidic volume and to connect a second electrode that includes a surface of silver metal disposed within the microfluidic volume. The processor is to apply an electrical potential between the electrode and the second electrode when the microfluidic volume contains a fluid that contains chloride ions to form a layer of silver chloride on the surface of the second electrode. The processor is further to cease application of the electrical potential and operate the second electrode as a reference electrode in a measurement process performed within the microfluidic volume.

Abstract: An example device includes a processor to connect to an electrode disposed within a microfluidic volume and to connect a second electrode that includes a surface of silver metal disposed within the microfluidic volume. The processor is to apply an electrical potential between the electrode and the second electrode when the microfluidic volume contains a fluid that contains chloride ions to form a layer of silver chloride on the surface of the second electrode. The processor is further to cease application of the electrical potential and operate the second electrode as a reference electrode in a measurement process performed within the microfluidic volume.