Fluorescence Spectroscopy Applied to Monitoring Biodiesel Degradation: Correlation with Acid Value and UV Absorption Analyses

Table 1

Fatty acid methyl ester composition in biodiesels from Sesamum indicum L. and Raphanus sativus L. [16].

Fatty acids (%)	Description	S. indicum L.	R. sativus L.
Palmitic	C 16  :  0	8.54 ± 0.03	6.38 ± 0.66
Palmitoleic	C 16  :  1	0.00 ± 0.00^A	0.33 ± 0.01^A
Stearic	C 18  :  0	6.83 ± 0.01	2.32 ± 0.14
Oleic	C 18  :  1(n-9)	34.12 ± 0.09	31.72 ± 2.14
Vaccenic	C 18  :  1(n-7)	0.00 ± 0.00^B	0.00 ± 0.00^B
Linoleic	C 18  :  2(n-6)	48.86 ± 0.08	18.35 ± 1.27
Arachidic	C 20  :  0	0.87 ± 0.03^C	0.93 ± 0.06^C
Eicosenoic	C 20  :  1	0.18 ± 0.01	8.80 ± 0.59
Linolenic	C 18  :  3(n-3)	0.41 ± 0.00	11.38 ± 0.67
Docosanoic	C 22  :  0	0.19 ± 0.01^D	0.53 ± 0.03^D
Erucic	C 22  :  1	0.00 ± 0.00	17.89 ± 1.13
Lignoceric	C 24  :  0	0.00 ± 0.00^E	0.63 ± 0.04^E
Nervonic	C 24  :  1	0.00 ± 0.00^F	1.80 ± 0.29^F
Σ saturated	—	16.43 ± 0.02	10.79 ± 0.93
Σ monounsaturated	—	34.30 ± 0.09	60.54 ± 4.16
Σ polyunsaturated	—	49.27 ± 0.08	29.73 ± 1.94

Values are mean ± sd (standard deviation) (n = 3) expressed as a percentage in relation to total fatty acids quantified. Values on the same line highlighted by equal superscript letters indicate no significant differences ().