Natural abundant 17O NMR in a 1.5-T Halbach magnet

We present mobile, low‐field 17O NMR as a means for monitoring oxygen in liquids. Whereas oxygen is one of the most important elements, oxygen NMR is limited by a poor sensitivity related to low natural abundance and gyro‐magnetic ratio of the NMR active 17O isotope. Here, we demonstrate 17O NMR detection at a Larmor frequency of 8.74 MHz in a 1.5‐T Halbach neodymium magnet with a home‐built digital NMR instrument suitable for large‐scale production and in‐line monitoring applications. The proposed 17O NMR sensor may be applied for direct, noninvasive measurements of water content in, for example, oil, manure, or food in automated quality or process control. Copyright © 2015 John Wiley & Sons, Ltd. We present mobile, low‐field 17O NMR as a means for monitoring oxygen in liquids. Whereas oxygen is one of the most important elements, oxygen NMR is limited by a poor sensitivity related to low natural abundance and gyro‐magnetic ratio of the NMR active 17O isotope. Here, we demonstrate 17O NMR detection at a Larmor frequency of 8.74 MHz in a 1.5‐T Halbach neodymium magnet with a home‐built digital NMR instrument suitable for large‐scale production and in‐line monitoring applications.