The 1H-13C HMQC-TOCSY experiment combines 1H-13C HMQC and 1H-TOCSY experiments to give through-bond correlations between a 13C-attached 1H to all other coupled 1H. The coupled 1H's can be seen along a line at the same 13C chemical shift from the carbon atom attached to the primary 1H. The spectrum should be compared with a 1H-13C HSQC or HMQC spectrum. The differences between a HSQC-TOCSY and HMQC-TOCSY is the same as mentioned here. The HSQC-TOCSY sequence is generally recommended over the HMQC version.

The following figure is the Varian 2D gradient-selected, phase-sensitive 1H-13C HMQC-TOCSY pulse sequence (varian name: gHMQCTOXY) with the main parameters displayed (NMR500).


Procedure (on NMR500)

Default parameters

The default setting (modified from Varian's default values) in our parameter set uses the following for a quick 2D experiment:

Data Processing

You can use vnmrJ to process the data by clicking autoprocess, but vnmrJ's graphics display for 2D spectrum leaves much to be desired. A separate program is strongly recommended for detailed processing and analysis.

One of the most widely used free processing/display software package for multi-dimensional NMR data processing is nmrPipe/nmrDraw. This program package has been installed on NMR500 and the data station. Follow this procedure to process data with nmrPipe/nmrDraw.

Example spectrum collected on NMR500

Sample: Strychnine at ~ 25mg/mL (~ 100mM) in cdcl3
  • Data collected October 2010 (~43 mins with nt=8)
  • TOCSY mixing time: 80 msec
  • Processed and displayed with nmrPipe/nmrDraw

ghmqctoxy spectrum

H. Zhou Updated Nov 2010