Hypercomplex NOESY Data
Varian (and JEOL) acquires some phase-sensitive data (such as NOESY) as hypercomplex, meaning that 2 FIDs are acquired for each t1 time point, with a phase shift of one pulse in the sequence. After FT in the direct dimension, the pairs of spectra are combined to create complex interferograms in the indirect dimension.
Varian phase-sensitive NOESY of strychnine.
This data set can be downloaded, along with processing macros.
NUTS-Pro versions newer than May, 2002, include a modified arrayed mode for that allows phasing in both dimensions after processing. Commands for processing are listed below.
Users with the standard 2D version cannot use Arrayed Mode, and can process with a different macro (below).
Import the fid, then process using the following series of commands:
|PT||set processing type to 2D_HyperComplex|
|AR||enter arrayed mode (note that status bar says “pairwise complex arrayed mode”|
|S#||set phase shift for sine multiplication to 90|
|MS MS||apply cosine squared window function|
|PH||phase while viewing the first slice; on exiting phase routine, the entire data set is phased|
|ZF||zero-fill (may be repeated if needed)|
|FT||may require phasing; see 2D phasing|
|SR||may or may not be needed to make diagonal run in the conventional direction|
|TD||to view data with direct dimension horizontal|
|MH||set minimum height to 0.3 (good starting guess for contour threshold)|
All quadrants of the data are retained, allowing phasing in both dimensions. See details. Be sure to save the processed data.
Macro using Arrayed Mode
NUTSMACRO Varian noesy in arrayed mode ; for hypercomplex data ask fileimport im 2f pt 2D_hypercomplex, 2n, set ARRAY_PAIRWISECOMPLEX set s# 90 ms ms ft ; transpose td ; process using zero-fill ms ms zf ft td set mh 2 ss ip end
Note that the processed data have not been saved. Phasing in one or both dimensions may be needed. See 2D phasing.
Before running the macro, import the data with IM. The macro start by prompting for a data file to open – select the translated NUTS file, which always starts with $.
Processing is done one 1 slice at a time, so the sequence of commands is done in a Link, which is repeated for each slice.
Before running the macro, import the data, FT and phase. When the macro starts, it will ask for a file to open – select the translated file. Temporary files are written at each stage of processing, so the macro must reset the file names at each stage. Be sure to save the final result.
set sl 1
|Before running macro, open data set, FT and phase 1st sliceMacro asks for name of data set to open – supply translated file name|
|set filec ft1.2d|
set s# 90
|window fcn will be cosine squared; phase is set with S#|
|ga bc ms ms ft ps bc tr ia ga bc ms ms ft ps bc tr st in||Link to process 1st dimensionGA reads in the first slice|
BC removes DC offset of the 2 halves of the FID
MS MS applies cosine squared
BC after FT removes DC and tilt in baseline
TR “tags” this to be the real half of the complex FID in t1
IA increments slice counter for File A
GA reads in the next slice, which is processed same way
TR “tags” this to be the imaginary half of the complex FID in t1
ST saves the 2 halves, and IN increments the file pointers and loops to the beginning of the Link
|set filec td.2d|
set filea ft1.2d
set sl 1
|reset file namestranspose data|
|set filea td.2d|
set filec ft2.2d
|reset file names|
|set sl 1|
ga ms ms zf ft sc in
|2nd dimension processing|
|set filea ft2.2d|
set sl 1
set mh .3
|reset file namesset contour threshold (MH = 0.3), set scale, display intensity plot|
This macro ends displaying data with the indirect dimension on the horizontal axis. This is because usually some phasing is needed. See 2D phasing.
Last updated: 3/23/05