We study the influence of electric fields on 3D surfactant-covered drops using a spectrally accurate boundary integral method. Surfactants (surface-active-agents) are compounds that change the surface tension between liquids and are widely used in engineering applications, and their evolution is modeled by a surface pde: the convection-diffusion equation. The dynamic of the drops is governed by the Stokes equations, while the leaky dielectric model is used to study the influence of the external electric field. I will talk about the main numerical tools developed to deal with these kinds of microfluidic simulations and I will show some interesting numerical results.