Fig. 2.

A comparison of ¹³C CP MAS (thin line) and ¹³C CHHC-filtered (t₁ = t_mix = 0, τ_CP = 65 μs for the last two CP steps) spectra (thick line) for (a) U-¹³C and (b) U-¹³C^dil_10% L-Tyrosine·HCl. The contact pulse for the first CP step in the CHHC experiment (and the only CP step in the CP MAS experiment) was of duration 700 μs. For both experiments, 32(U-¹³C) and 256 (U-¹³C^dil_10%) transients were co-added for a recycle delay of 3 s.