Table 6 Comparison of several analytical methods, reaction types observed and species detected during oxidation of linseed oil

FTIR

Hydroxyl group formation

Hydroxyl group

3430 cm^-1

(Lazzari & Chiantore1999)

Double bond decreasing in abundance

Cis double bond

3011, 1654, 722 cm^-1

(Lazzari & Chiantore1999)

The cis- trans isomerisation reaction and changes of conjugation

Trans conjugated double bond

987, 971 cm^-1

(Oyman et al.2005a; Mallégol et al.2000)

The broadening of carbonyl peak

Carbonyl compounds

1747 cm^-1

(Lazzari & Chiantore1999)

H-NMR

Decreasing the abundance of cis double bonds

Non-conjugated cis double bonds

5.4 ppm

(Oyman et al.2005a; Miccichè et al.2006)

Decreasing the abundance of double allylic hydrogen

Double allylic hydrogen

2.7 ppm

(Oyman et al.2007)

The changes in conjugation

Conjugated double bond

5.5-6.6 ppm

(Oyman et al.2005a; Miccichè et al.2006)

Formation of conjugated hydroperoxides

Conjugated ethyl linoleate hydroperoxide

7.9 and 8 ppm

(Miccichè et al.2006)

Isomerisation of cis double bonds

Allylic methane

4.3 ppm

(Miccichè et al.2006)

Disappearance of vinylic hydrogen

Vinylic hydrogens

5.3 ppm

(Martini et al.2009)

Epoxidation reaction

Epoxy groups

2.9-3.1 ppm

(Martini et al.2009)

Raman

Changes of double bond abundance

Non-conjugated cis double bond

1265, 1655 cm^-1

(Oyman et al.2005a)

Changes of conjugation structure

Conjugated double bond

1599, 1634 cm^-1

(Oyman et al.2005a)

Oxirane group formation

Trans-9,10- and cis-9,10-epoxystearic acids

1064, 1295, 1443 cm^-1

(Muik et al.2005)

Carbonyl formation

Saturated aldehydes

1725 cm^-1

(Muik et al.2005)

Conjugated unsaturated aldehydes

1690 cm^-1

UV–vis

Formation of ligand complex of cobalt catalyst

Co(II) octoate solution in toluene

590 nm

(Tanase et al.2004)

Hydroperoxide formation

Conjugated diene

232-232.5 nm

(Belhaj et al.2010; Hendriks et al.1979)

Chemiluminescence

Hydroperoxides formation

Hydroperoxides

(Rolewski et al.2009)

Oxygen uptake

Oxygen consumption

(Oyman et al.2005a)

DSC-TGA

Thermal decomposition reactions

(Lazzari & Chiantore1999)

Reaction exotherm profiles

(Tuman et al.1996)

HPLC

Identification and quantitation of aldehyde emissions

Aldehydes compounds such as ethanal, propanal, pentanal, hexanal.

(Fjällström et al.2002)

GC-MS

Fatty acid composition

Fatty acid methyl esters

Retention times depend on the columns and methods

(García-Martínez et al.2009)

MALDI-RTOF-MS and ESI-MS

Triacylglycerol composition

Triacylglycerols

Based on mass-to-charge ratio (m/z)

(Krist et al.2006)

SPME-GC-MS

Identification and quantitation of VOC

Saturated and unsaturated hydrocarbons

Retention times depend on the columns and methods

(Krist et al.2006; Jeleń et al.2000; García-Martínez et al.2009; Lee et al. 105; Lee & Min2010)

Aldehydes, ketones, carboxylic acids, alcohols, furans

Aromatic compounds

SEC

Polymerisation (cross-linking) reaction

Hydroperoxides

Retention time varies

(Lazzari & Chiantore1999; Miccichè et al.2006)

Dimeric fraction

Higher oligomer

EPR/ESR (discussed later in this paper)

Radical formation

Allylic, pentadienyl, peroxyl, hydroxyl, alkoxyl radicals

(Zhu & Sevilla1989; Dikalov & Mason2001)

Metal-dioxygen complexes

(Yamada et al.1984)