X COLOC Experiment

The original COLOC sequence did not attempt to suppress l J(C, H) correlation peaks using a low-pass J filter, which is part of the HMBC experiment (section 5.8.3). The authors who proposed the COLOC sequence [5.170] stated that there would be no practical improvement using additional 1J(C, H) suppression elements [2]. However, several modified COLOC experiments have been published to suppress H(C, H) correlation peaks and spectrum artefacts that are introduced by pulse imperfections. The BIRD-COLOC sequence [3] uses two BIRD units to suppress the one-bond IH, correlation peaks [5.182]. The alternative TANGO-COLOC [5.183] is similar to the BIRD-COLOC experiment except that a TANGO unit replaces the first BIRD unit. The S-COLOC sequence [5.94] utilizes the COLOC-TANGO sequence plus an additional 180° pulse to enhance the constant-time procedure. 

In the following Check it two alternative COLOC-related experiments TANGO-COLOC and S-COLOC versions are compared. 

Open the configuration file ch5622a.cfg and simulate the TANGO-COLOC experiment. Use the file ch5622b.cfg to calculate the S-COLOC sequence spectrum. 

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