In situ quantification of Cu(II) during an electrodeposition reaction using time-domain NMR relaxometry

The use of a low-cost benchtop time-domain NMR (TD-NMR) spectrometer to monitor copper electrodeposition in situ is presented. The measurements are based on the strong linear correlation between the concentration of paramagnetic ions and the transverse relaxation rates (R(2)) of the solvent protons. Two electrochemical NMR (EC-NMR) cells were constructed and applied to monitor the Cu(2+) concentration during the electrodeposition reaction. The results show that TD-NMR relaxometry using the Carr-Purcell-Meiboom-Gill pulse sequence can be a very fast, simple, and efficient technique to monitor, in real time, the variation in the Cu(2+) concentration during an electrodeposition reaction. This methodology can also be applied to monitor the electrodeposition of other paramagnetic ions, such as Ni(2+) and Cr(3+), which are commonly used in electroplating.