Composition and structure of natural organic matter through advanced nuclear magnetic resonance techniques

Chemical and Biological Technologies in Agriculture

Table 2 Functional groups (%) detected in ¹³C CP/TOSS NMR Spectra of demineralized sediments (DM) collected at different sites (B1, A01, and A04) from the Pearl river delta and their fractions (LF and NHC)

Samples	Alkyl C 0–48 ppm	OCH₃/NCH 48–65 ppm	Alkyl C–O 65–91 ppm	O–alkyl–O 91–110 ppm	Arom C–C 91–150 ppm	Arom C–H 91–150 ppm	Arom C–O 150–165 ppm	COO/NC=O 150–165 ppm	(CH₂)n	Aromatic C^a	Polar C^b
DM
B1	27.4	12.0	15.9	3.27	18.6	13.0	4.36	5.57	8.30	35.9	46.1
A01	32.4	11.8	13.6	3.56	15.6	12.3	4.81	5.84	9.50	32.8	45.6
A04	25.6	11.8	14.6	4.83	23.0	7.38	5.46	7.29	7.70	35.9	46.9
LF
B1	22.0	12.6	17.2	3.08	19.6	14.9	4.68	5.89	6.50	39.2	46.9
A01	27.3	12.9	13.6	3.04	19.8	11.3	5.30	6.73	8.30	36.4	46.8
A04	23.0	12.2	15.6	3.25	21.0	12.7	5.19	7.21	6.40	38.8	46.6
NHC
B1	24.6	9.39	8.12	1.05	23.6	22.7	5.62	4.95	7.90	51.9	36.0
A01	29.2	9.43	8.37	1.32	22.1	18.7	5.94	4.95	10.7	46.7	39.4
A04	24.0	8.81	8.15	1.18	26.2	19.1	6.68	5.87	7.70	52.0	37.2

^a Aromatic C aromatic C–C (91–150 ppm) + aromatic C–H (91–150 ppm) + aromatic C–O (150–165 ppm) (%)
^b Polar C polar aliphatic (48–91 ppm) + polar aromatic and C=O (150–190 ppm)