gHSQC

Set up appropriate 1H parameters. Normally should acquire 1D ¹H spectrum first.

pw = ¹H pulse, should be 90º pulse

tpwr = high power for ¹H; should be set according to pw, or is correlated to pw.

nt = number of scans, should be multiple of 2, but 1 is acceptable

ni = number of t1 increments, points in t1 dimension, at least 64, 128 is preferable

np = number of points in t2 dimension, must be even number, 2048 is standard

d1 = relaxation delay; normally should be slightly longer than in gCOSY, so 1.5 seconds is normal, but aromatic (or vinyl or methyl) protons usually need 2.0-2.5 seconds for optimal signal-to-noise

Steps:

1) Acquire 1 scan of 1H 1D experiment. Set cursors ~0.5 ppm beyond last proton resonance on both sides of spectrum, type command:

movesw

2) Re-acquire 1H 1D experiment (this is only required for 1H 1D on side of 2D spectrum)

3) Move parameters to another experiment. To move parameters from experiment 1 to experiment 3 type command:

mp(1,3)

4) Change to experiment 3, type command:

jexp3

5) Set gHSQC parameters with setup macro, type command:

gHSQC (for sensitivity enhanced HSQC user macro gHSQCSE)

6) Spin will likely turn off, if it does not, open Acqi window and manually turn it off. Lock Level should not drop more than ~5 %-10 %. If it does, you should reshim non-spin shims- X1, Y1, XZ, and YZ, and on higher field (500/600) X2Y2 and XY

7) Set the number of scans (nt) to appropriate value, generally 1 or 2 (it is preferable for nt to be a multiple of 2; nt might need to be increased for sufficient signal-to-noise, generally nt = 2 is sufficient if decent 1H spectrum can be acquired in 32 scans), type:

nt=2

8) Set the number of points in t1 dimension (second dimension) (ni), generally 128-256 are suggested, 128 is normally sufficient, type:

ni=128

9) Set d1 time, normally should be slightly longer than in gCOSY, so 1.5 seconds is normal, but aromatic (or vinyl ) protons especially in non-viscous solvent usually need 2.0-2.5 seconds for optimal signal-to-noise

10) Set the parameters sw1, dof, and j1xh; sw1 = spectral width in 13C dimension, the default is ~-10 to 160 ppm; if you have a protonated 13C beyond that range then sw1 must be increased or dof (the center of the carbon spectrum must be changed); the default value of j1xh (the 1-bond 1H/13C coupling constant) is 140 Hz, which is approximately correct for aliphatic proton/carbon pairs, aromatic 1-bond 1H/13C coupling constants are 170-250 Hz, so j1xh = 180

11) Start acquisition, type command:

go

12) Process data with VNMR: processhsqc

13) If spectrum has yellow streaks and purple streaks horizontally across the spectrum, then the spectrum should be phased; set cursor on peak, type:

ds

then manually phase, be careful to only click once on spectrum during phasing, only rp (or rp1 phase correct should be changed)

redraw 2D type:

dpn10

If spectrum still has streaks in horizontal direction more phasing is required including lp (or lp1) phase correct. If spectrum has yellow/purple streaks in vertical direction, then the other dimension needs to be phased, so switch the axes, type:

trace = 'f1' (or 'f2', depending upon which axis is currently the x-axis, then type:

dpn10

14) Spectrum should be appropriately referenced already, but you should confirm this; if necessary re-reference by putting cursor on appropriate diagonal peak and type (assuming CDCl3):

rl(7.26p)

rl1(77d)

dpn10

15) Adjust vertical scale with vs +20% and vs -20% menu buttons or with middle mouse button or manually changing the parameter, vs2d, so vs2d = 100 (the lower the number, the less noise displayed), then redraw 2D with dpn10 command

16) Print with full rectangle, type:

full

dpn10

pn10

for only positive peaks:

p10

for only negative peaks:

n10

17) Save data, type:

svf('filename')