# Two-dimensional nuclear magnetic resonance spectroscopy with a microfluidic diamond quantum sensor

## TL;DR

This paper demonstrates high-resolution two-dimensional NMR spectroscopy using a microfluidic diamond quantum sensor, significantly improving spectral resolution and enabling analysis of tiny sample volumes for chemical and biological applications.

## Contribution

It introduces a microfluidic platform that separates polarization and detection phases, achieving unprecedented spectral resolution in diamond-based NMR spectroscopy.

## Key findings

- Spectral resolution of 0.65 Hz achieved
- Performed 2D correlation spectroscopy on ~20 picoliter samples
- Significant advancement for mass-limited chemical and biological analysis

## Abstract

Quantum sensors based on nitrogen-vacancy centers in diamond have emerged as a promising detection modality for nuclear magnetic resonance (NMR) spectroscopy owing to their micron-scale detection volume and non-inductive based detection. A remaining challenge is to realize sufficiently high spectral resolution and concentration sensitivity for multidimensional NMR analysis of picoliter sample volumes. Here, we address this challenge by spatially separating the polarization and detection phases of the experiment in a microfluidic platform. We realize a spectral resolution of 0.65 +/- 0.05 Hz, an order-of-magnitude improvement over previous diamond NMR studies. We use the platform to perform two-dimensional correlation spectroscopy of liquid analytes within an effective ~20 picoliter detection volume. The use of diamond quantum sensors as in-line microfluidic NMR detectors is a significant step towards applications in mass-limited chemical analysis and single cell biology.