NMRanalyst's AssembleIt workwindow contains the FindIt, VerifyIt, and AssembleIt components.

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 NMRanalyst's AssembleIt workwindow contains the FindIt, VerifyIt, and AssembleIt components.

 http://www.sciencesoft.net/NMRanalyst_Manual/HTML/overview.html

 NMRanalyst automates the analysis of one to three dimensional NMR spectra. It reduces experimental multidimensional NMR data to a list of detected spin systems, eliminating the tedious manual interpretation of raw NMR data. NMRanalyst's AssembleIt workwindow contains the FindIt, VerifyIt, and AssembleIt components. The FindIt component identifies the best matching structures for analysis results. It contains over 15.9 million common molecular structures and further ones can be added. The VerifyIt component rates a specified structure by its agreement with NMR results. It can compare the rating with all the FindIt structures for further confirmation of the specified structure. The AssembleIt component performs the structure elucidation. It combines the analysis results of several spectra and derives the most likely molecular skeletons from this often incomplete and ambiguous information.

The NMRplot program displays experimental, simulated, and residual spectra as contour, surface, and isosurface plots. The NMRgraph program displays and allows editing molecular structures. It predicts proton and carbon chemical shifts. It completes determined molecular skeletons by adding likely bond multiplicities and NMR unobserved heteroatoms.
The NMRanalyst spectral analysis software is based on a mathematical spin system model. NMRanalyst analyzes all acquired phase components simultaneously for maximum sensitivity. This provides maximum sensitivity for various types of multidimensional spectra. This approach contrasts with other computerized analysis strategies, such as peak picking, which ignore valuable spectral information. By using this novel mathematical approach, NMRanalyst often excels compared to even an experienced spectroscopist in the sensitivity, reliability, accuracy, and speed of the data analysis.
The software supports the analysis of the following and equivalent spectrum types:

• Adequate sensitivity DoublE-QUAnTum spEctroscopy (ADEQUATE),
• Double-Quantum Filtered COrrelation SpectroscopY (DQF-COSY),
• HETeronuclear CORrelation (HETCOR),
• Heteronuclear Multi-Bond Connectivity (HMBC),
• Heteronuclear Single Quantum Coherence (HSQC, HMQC),
• Incredible Natural Abundance DoublE-QUAntum Transfer Experiment (INADEQUATE),
• Nuclear Overhauser Effect SpectroscopY (NOESY),
• Rotating frame Overhauser Effect SpectroscopY (ROESY),
• TOtal Correlation SpectroscopY (TOCSY), and
• 3D spectra.

1.1 The Automated Spectral Analysis

The first application of NMRanalyst was for 2D INADEQUATE spectra. The schematic explains this application for a >CH-CH₂-CH₃ molecular fragment. Its 1D proton decoupled ¹³C spectrum is shown at the back of the schematic. In the 2D spectrum, a pair of bonded carbons (e.g., CH-CH₂) gives rise to a pair of anti-phase doublets, centered at the chemical shifts of the two carbons (v_A and v_B), and split approximately by the carbon-carbon coupling constant (J). Each of these AB spectral patterns is displaced along the F1 axis by the sum of the two relevant chemical shifts, v_A+v_B.
This spin system results in a bond pattern for each pair of bonded carbons symmetrically disposed about the diagonal as shown. Because the double-quantum frequency (in F1 direction) is the sum of the chemical shifts of the two coupled carbons, an initial analysis of a proton decoupled 1D carbon spectrum can be used to identify the regions of the 2D INADEQUATE spectrum which may contain correlation signals. For each pair of resonances identified in the 1D spectrum, two small regions of the spectrum are defined by the small rectangles shown in the figure above. In case of a bond between the two carbons under consideration, the characteristic pattern is contained within this "fitting area". Here, the AB and BC fitting areas contain the required patterns, but the AC fitting area does not, consistent with the bonding of the three-carbon fragment shown. The objective of NMRanalyst is to examine the fitting area appropriate for each pair of carbon resonances and to determine whether or not it contains a correlation (bond) signal.

This analysis strategy extends to other spectrum types by using the appropriate spin-system model. Shown in this schematic is the DQF-COSY spin system. The spectrum contains an active coupling of two protons. Each correlation (coupling) signal is composed of 16 anti-phase transitions. The spectral diagonal is normally overly crowded and NMRanalyst only examines the off-diagonal transitions in the two shown fitting areas. What can be improved by using this automated spectral analysis?

1. A major limitation of NMR is its lack of sensitivity. A phase sensitive 2D dataset is acquired with four phase components and each phase sensitive 3D dataset with eight. Half of the phase components are acquired sequentially and hence their noise content is uncorrelated. NMRanalyst evaluates all phase components simultaneously by nonlinear regression analysis, making full use of the acquired data.
2. The visual spectrum analysis can be described as "pattern recognition". What sticks out of the noise level and looks like an expected signal? Can this signal be assigned to other signals in the same or other spectra or is it perhaps a spectral artifact?NMRanalyst looks for the whole spin system, potentially consisting of several transitions. NMRanalyst starts with 1D resonance information and only searches the areas in the multidimensional spectrum which could contain spin systems. The automated analysis is more selective than the visual pattern recognition. It is also more sensitive as it can reliably detect signals even for signal-to-noise challenged spectra where resonances are not visible.
3. The molecular structure determination using NMR remains labor intensive. Why not automate the steps which don't require the creative capabilities of a spectroscopist? "Spectroscopist-In-A-Box" is our goal for NMRanalyst. Things remain to be improved, but NMRanalyst already effectively supports using NMR as a structure elucidation tool.

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