APT, attached proton test

APT Attached proton test, a modification of the J-modulated spin-echo experiment to determine C//multiplicities, a less sensitive alternative to DEPT... 

A/E, absorption-emission CIDNP net effect APT, attached proton test... 

C-NMR spectra (10) of salicylic acid in DMSO-de (Figs. 4-6) was recorded on a Varian XL-200 NMR spectrometer. The multiplicity of the resoanance was obtained from APT (Attached Proton Test) program. The 13C-NMR spectrum displayed all the seven carbons resonances. The carbon chemical shifts assignments are presented in Table 4. 

APT (attached proton test) Spin echo based selection of multiplicities of signals. Quaternary C and CH2 carbon atoms give positive signals (Peak UP), while CH and CH3 give negative signals (Peak DOWN). 

The broadband decoupler is moved several thousand Hz from the proton frequency of TMS this results in residual 5 (i.e, reduced) coupling by directly attached proton, thus reducing overlap of signals. However, overlap remains a serious problem, t Distortionless Enhancement by Polarization Transfer. As the name implies, sensitivity is increased by polarization transfer from the more sensitive coupled prolon(s) to the less sensitive 13C atom. The APT (Attached Proton Test see Sanders (1993)) gives similar information but lacks the sensitivity of DEPT. 

C-NMR spectrum (12) of clonidine hydrochloride Fig. (7-9) was recorded in DMSO-de by Varian XL-200 MHz NMR spectrometer. The multiplicity of the resonances was obtained from DEPT (Distortionless enhancement by polarization transfer) and APT (attached proton test). The carbon chemical shifts are presented in Table (7). 

The nuclear magnetic resonance spectra presented in this book as well as Carbon-13 and standard APT (Attached Proton Test) experimental data are available in computer library form from General Electric NMR Instrument Division. 

APT attached proton test CZE capillary zone electrophoresis... 

Figure 11 (A) The APT (attached proton test) pulse sequence. (B) Behaviour of the magnetization due to a nc- H...

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