![]() ![]() Using non-tuned coils for NMR spectroscopy has been considered in the 60s of last century 21, 22 however, it has remained unexploited in the following decades of developments of ever higher field spectrometers. For multi-(frequency) channel probes, this implies multiple coils and/or multi-dip tuning circuits, making the probes very complex. For heteronuclear and multidimensional NMR experiments, sophisticated and complex electronic circuitry is required 17, 18, which limits the more widespread application and implementation of (microcoil) NMR spectroscopy.Ī classical NMR front end consists of a transmit/receive coil enveloping the sample and a tuning/matching circuit driven through a Z 0 (usually 50 Ω) coaxial cable 19, 20. Microcoils with different geometries have proven to be a successful sensitivity enhancement strategy for mass-limited samples 11, 12, 13, 14, 15, 16, although their use remains restricted to date mainly to 1D 1H-NMR spectroscopy. Investigation of mass-limited samples can also benefit from the reduction of the sample volume in miniaturized coils, since the amplitude of the NMR signal is optimal when the sizes of the coil and sample match 8, 9, 10. Methodologies to enhance the NMR sensitivity comprise expensive and technologically demanding solutions such as ultra-high magnetic fields 1, cryogenically cooled probes 2 and dynamic nuclear polarization schemes 3, 4, or more exotic alternative detection schemes like optical 5, or remote detection 6, or travelling wave NMR. However, the low sensitivity of NMR spectroscopy severely constrains its applications, particularly for mass- and volume-limited samples. Nuclear magnetic resonance (NMR) spectroscopy is one of the most versatile and powerful analytical tools used in chemistry, physics, biology and medicine. Importantly, the concept of a non-resonant system provides magnetic field-independent NMR probes moreover, the small-volume alleviates problems related to field inhomogeneity, making the broad-band coil an attractive option for, for example, portable and table-top NMR systems. Noteworthy, heteronuclear 2D experiments can be performed in a straightforward manner on virtually any combination of nuclides (from classical 1H– 13C to more exotic combinations like 19F– 31P) both in coupled and decoupled mode. Routine one-dimensional (1D) and two-dimensional (2D), homo- and heteronuclear experiments can be carried out using the broad-band coil set-up. Here we show that a non-resonant planar transceiver microcoil integrated in a microfluidic chip (detection volume 25 nl) can detect different nuclides in the full broad-band range of Larmor frequencies (at 9.4 T from 61 to 400 MHz). R-release (arm64): ChemoSpec2D_0.5.0.tgz, r-oldrel (arm64): ChemoSpec2D_0.5.0.tgz, r-release (x86_64): ChemoSpec2D_0.5.0.tgz, r-oldrel (x86_64): ChemoSpec2D_0.5.0.Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique, but its low sensitivity and highly sophisticated, costly, equipment severely constrain more widespread applications. Knitr, tinytest, irlba, ThreeWay, multiway, parallel, matrixStats, R.utils, mlrMBO, ParamHelpers, smoof, mlr, lhs, RcppRoll, rmarkdown, robustbase, bookdown, CMLS Tools, utils, colorspace, readJDX, ggplot2 'ChemoSpec2D' takes many of its cues from 'ChemoSpec' and tries to create consistent graphical output and to be very user friendly. In addition to chemometric tools, a few tools are provided for plotting 2D spectra, but these are not intended to replace the functionality typically available on the spectrometer. Each 2D spectrum (a matrix) is treated as the unit of observation, and thus the physical sample in the spectrometer corresponds to the sample from a statistical perspective. 'ChemoSpec2D' deploys methods aimed primarily at classification of samples and the identification of spectral features which are important in distinguishing samples from each other. ChemoSpec2D: Exploratory Chemometrics for 2D SpectroscopyĪ collection of functions for exploratory chemometrics of 2D spectroscopic data sets such as COSY (correlated spectroscopy) and HSQC (heteronuclear single quantum coherence) 2D NMR (nuclear magnetic resonance) spectra. ![]()
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