The Program "Spin Works" fulfills two functions:

1. It provides easy basic off-line processing of 1D NMR data on PC's
2. It can simulate and fit complex second order spectra including NMR spectra of species undergoing exchange.

The program comes with nice Documentation and Tutorials for its use. Here are the basic commands to workup your data and simulate your spectra.

First, use the ssh program to transfer the data from our spectrometers to your PC. Then start the program Spin Works.

• Define your data file type by clicking Options -> Data Format -> Varian
• Import your data with File -> open -> click on fid file in the data directory on your PC.
• Define the weighting function with Edit -> Processing Parameters -> lb 0.5 Hz is our standard for proton spectra, 3 Hz for ¹³C data.
• "wft" your data with Processing -> "em + ft"
• Phase your spectra by click on the phasing icon. The program automatically chooses the largest peak, indicated with a green line, as fixed point for the 1st order phasing. So phase that peak correct with the 0-order phasing and phase the rest of the spectra with the 1^st order parameter. You do this by sliding the bars until correct. Click "apply and exit". Use black + or - to look at detailed vertical scale, to determine the phasing quality.
• Baseline corrections are very important for fitting of patterns! First, define the points that characterize the baseline curve by clicking on the icon b pt and selecting points densely enough with the left mouse button on the baseline. Then choose Processing -> Automatic Baseline (least square) or Automatic Baseline (SVD).

For successful simulations you have to have a good baseline!!! Also, usually, simulations are an iterative process and work the best, the better your starting parameters are. Prepare your input data by switching the axis to Hz (Unit icon) and read out the chemical shift values and differences between peaks by clicking on one peak and reading out the displayed values at the bottom.

• Enter the starting parameters: Select Spin Systems -> Edit Chemical Shifts :

Enter the appropriate values, for example Group 1 : 1 ( number of spins)

label : A

species : proton

chemical shift : in Hz

• Select Spin Systems -> Edit Scalar (J) Couplings: Only enter the numerical part of these entries. Do not change the coupling labels.
• Select Simulation -> Run NUMMRIT Simulation. A blue simulated spectrum will appear above the experimental spectrum. Use the blue + and – up-arrow or down arrow symbols to compare the two spectra.
• Assign experimental peaks to transitions: The left and right keyboard arrow keys will move a transition cursor across the simulated spectrum. Assign lines in the experimental spectrum to these transitions by pointing to the corresponding experimental peak and clicking with the right mouse button. A red line will connect the transition to its corresponding peak. A misassigned transition can be deleted with the keyboard "d" key.
• Under Spin Systems -> Edit Chemical Shifts and Spin Systems -> Edit Scalar (J) Couplings check the iterate boxes for the parameters you want to have fitted. If you can separate parameters, use a limited set. For example, a well-separated triplet allows you to determine its chemical shift and one coupling parameter independently of the related pattern.
• Under Simulation -> Edit Simulation Parameters -> check Optimize, Autoignore, and Autoassign boxes.
• Repeat Simulation -> Run NUMMRIT Simulation. Now the spectrum will be fitted.
• If the simulation was satisfactory, load the new parameters (Spin System -> Load optimized Parameters) into the spin system editor. You may improve on the simulation by either manually giving new start parameters or by reassigning experimental peaks to transitions. In that case re-run the simulation. You can examine the simulation output (Simulation -> List Simulation Output) and check the RMS deviation between the experimental and calculated spectra.
• You can load the final optimized parameters (Spin System -> Load Optimized Parameters) and save the new spin system (File -> Save Spin System As) and the assigned transitions (File -> Save Assigned Transitions As ..) to disk for later use.