# Full-Signal Ultrahigh-Resolution NMR by Parameter Estimation

## TL;DR

A new method called CUPID improves NMR sensitivity by using all available signal, enabling high-resolution spectra even at low sample concentrations.

## Contribution

CUPID introduces a novel parameter estimation approach for pure shift NMR that utilizes full signal from 2DJ data.

## Key findings

- CUPID produces usable spectra at lower concentrations than existing methods.
- The method allows extraction of individual multiplet structures from overlapping signals.
- CUPID is available as an open-source Python package with a user-friendly interface.

## Abstract

Pure shift NMR spectra,
in which multiplet structure
is suppressed,
are widely used but exact a high price in sensitivity. Here we present
CUPID (Computer-assisted Undiminished-sensitivity Protocol for Ideal
Decoupling), which uses parametric estimation to produce pure shift
NMR spectra from easily acquired 2D J-resolved (2DJ) data sets. Unlike
previous practical methods for broadband pure shift NMR, it makes
use of all of the available signal. CUPID is therefore effective even
at sample concentrations where current methods are too insensitive
to yield usable spectra. As an additional benefit, the estimation
method used allows the extraction of individual multiplet structures
from overlapping spectra. CUPID is freely available through NMR Estimation
in Python (NMR-EsPy), an open-source package with
a simple-to-use API, and comes with a graphical user interface that
is accessible via Topspin, a widely used NMR software platform.