Interfacing a microfluidic electrophoresis chip with inductively coupled plasma mass spectrometry for rapid elemental speciation

Abstract

A microfluidic chip based electrophoresis system was interfaced with inductively coupled plasma mass spectrometry to provide rapid elemental speciation capabilities. The chip had an 8 cm long, 100 µm wide and 20 µm deep separation channel etched in a serpentine pattern on the glass base plate (30 × 25 × 3 mm). Hydrodynamic sample injection was accomplished by a flow injection mode through an externally controlled gravity pump and a three-way valve. With application of an electric field up to 500 V cm⁻¹, species such as Cr(III) and Cr(VI), Cu(II) and Cu(EDTA)²⁻ were separated in acidic solution within 30 s. The separation of As(III) and As(V) was achieved in an alkaline buffer system by using hydrodynamically modified electroosmotic flow (HMEOF) to control the fluid. The quantification of these species is also reported.