Basic HSQC sequence with States-TPPI quadrature detection 1H coupled HSQC-13C peaks are split by C-H couplings in /4.Jrs 中31 01=x,-=x States-TPPI 2=x,x,-6,x 1H decoupled HSQC-13C peaks are singlets in 01 at natural abundance, 031=K,一x,-x,x split by 13C-13C couplings in 13C labeled systems +States-TPP 12 4 1/4US Φ31 1/2 gradients must be of opposite signs to continue to dephase I spins not coupled to S