INEPT Intensive Nucleus Enhancement

INEPT — Intensive Nucleus Enhancement by Polarization Transfer... 

This is just following the rules for each individual operator in the product (Fig. 7.15). The resulting product operator, 2SXIZ, can be described as 13C magnetization on the xf axis, antiphase with respect to the z magnetization (a or p state) of its attached H nucleus. Acquisition at this time would yield an FID at the 13C frequency, and Fourier transformation with phase reference - -x would give a carbon doublet with a downfield component of normal phase and an upheld component of opposite phase (upside-down). This is what you will see in your INEPT spectrum an antiphase 13 C doublet. Later, we will see that this spectrum is actually four times as intense as the normal 13C spectrum this is the enhancement part of INEPT. 

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