156 Marine Macro- and Microalgae: An Overview
3,3,4,4,5,5-d 6 -5-sulfonate sodium salt (DSS) as the primary reference for both
1
H and
13
C-NMR
spectroscopy in highly polar solvents. For most purposes, the difference between DSS and TMS when
dissolved in the same solvent is negligible and, therefore, the data from DSS and TMS scales may be
validly compared without correction (see Table 5) (Harris et al. 2001).
Fig. 3. (a) FT-Raman spectrum of ground seaweed (Chondrus crispus female gametophyte) treated with a mixture of acetone
and methanol. (b) FT-Raman spectrum of fresh seaweed treated with calcium hypochlorite 4% (30 s), then dried and ground.
(c) FT-Raman spectrum of ground seaweed (obtained from a herbarium sample) treated with calcium hypochlorite 4%
(30 s). (d) FT-Raman spectrum of C. crispus extracted carrageenan (after Pereira et al. 2009b).
Table 5. Chemical shifts for common internal standards for NMR-spectroscopy in aqueous systems (adapted from van de
Velde et al. 2004; Pereira 2004; Pereira 2016).
Compound
Abbr.
Chemical shift (ppm)
Compound chemical name
13
C
1
H
DSS
0.000
0.000
2,2-Dimethyl-2-silapentane-3,3,4,4,5,5-d 6 -5-sulfonate sodium salt
TSP
–0.18
–0.017
3-(Trimethylsilyl) propionic-2,2,3,3-d 4 acid sodium salt
MeOH
51.43
3.337
Methanol
DMSO
41.53
2.696
Dimethyl sulfoxide
Acetone
32.69
2.208
Acetone
Recorded in D 2 O containing Na 2 HPO 2 (20 mM) at 65°C.
a
600
700
800
900
1000
1100
1200
1300
1400
Wavenumber (cm- 1 )