In this work it is demonstrated that the manipulation of the mesoscale-sized particles through Marangoni flows occurs during the transient regime of the convection cell evolution. By exploiting this fact, it was possible to selectively separate a single glass bead out of a group of other beads ranging from 150 to 212 μm. This task was accomplished by controlling the Marangoni convection cell growth. The growth was controlled by varying the pulse width of an infrared laser beam that acts as a thermal source. Thus, extending the use of the Marangoni flows for single particles sorting or manipulation.