Utilization of Dielectrophoresis for the Quantification of Rare Earth Elements Adsorbed on Cupriavidus necator

A new method of quantifying rare earth elements (REEs): light RREs (Neodymium - Nd (III), Samarium - Sm (III)) and heavy REE (Europium - Eu (III)) was investigated utilizing native Cupriavidus necator as biosorbent and dielectrophoresis (DEP) as the quantification technique. C. necator was characterized as a control (through the measurement of first and second crossover frequency) in a polymer (PDMS)-based point-and-planar microwell (PPM) platform at 8 Vpp (peak-to-peak voltage) AC signal and variable frequencies. Allied C. necator (Cupriavidus necator in its metal-bound state) was then characterized for each of the rare earth metals adsorbed. The first crossover frequency (fco1) was correlated with the amount of metal adsorbed that was obtained through spectrophotometry. The influence of pH, bio-sorbent dosage, initial REE concentration, and metal incubation period was also investigated. The crossover vs. concentration curve is plotted and that serves as a calibration curve such that when the crossover f...