2D Experiment Setup

General steps to set up a 2D experiment.

  1. Creating a data set
    • Use command "edc" to generate a new experiment set from the currently displayed experiment.
    • Or, use "rpar" command to read from an existing data set. For instance, "rpar HSQCETFPF3GP"  will create a new 1H-15N HSQC experiment.
    • If there is no exisiting experiment or data set available, and topspin has only the pulse program, then you will have to set parameters manually.
  2. Type "ased" to open the acquisition parameter window
    • Define/check the spectrum dimension and window position by setting parameters SW, O1P, O2P. Wrong setting may result in fold-back peaks.
    • Define spectrum resolution by setting parameters TD F1 and TD F2.
  3. Type "eda", to open pulse program parameter window.
    • Set power level and pulse length parameters including high power pulses, decouple pulses, shape pulses, and et al. 
      "getprosol 1H A B" command, in which A is the calibrated 90° proton pulse length, and B is the related power level, will set all pulse parameters for you based on the values provided in the command. This command also can be applied to other nuclei as well, such as "getprosol 13C A B". Note that this command may not work for customized pulse programs if the pulse definitions differ from the Bruker default.
    • Check/adjust NS, DS, D1, mixing time if required; Set gradient files and percentages defined in the pulse program; For a 13C and 15N double labeled sample, ZGOPTNS should be set to "-DLABEL_CN" for decoupling purpose.
  4. Check and adjust receiver gain using the command "rga" before starting the experiment, and the rg value should be set reservedly.
  5. Start the experiment using command "zg"
  6. Process the FID using command “xfb”, and phase the spectrum when necessary. Note that SI values (size of real spectrum) of both demensions should be reasonable (F2 =< 2K, F1=< 1K). Putting too large numbers will increase the file size, causing slow data processing and spectrum viewing. 

The layout of a 2D1H-15NHSQC