Contactless NMR Spectroscopy on a Chip

Inductively coupled planar resonators offer convenient integration of high-resolution NMR spectroscopy with microfluidic lab-on-a-chip devices. Planar spiral resonators are fabricated lithographically either by gold electroplating or by etching Cu laminated with polyimide. Their performance is characterized by NMR imaging as well as spectroscopy. A single-scan limit of detection LODt = 0.95 nmol S-1/2 was obtained from sample volumes around 1 mu L. The sensitivity of this approach is similar to that obtained by microstripline and microslot probes.