Table 1 Possible oxidative structures of tested monoterpenes related to observed molecular ions.

132

C₁₀H₁₂

M-4

− 4[H]

Loss of 4 hydrogens to form two double bonds from two –CH₂–CH₂− group

134

C₁₀H₁₄

M-2

− 2[H]

Loss of 2 hydrogens to form an double bond from –CH₂–CH₂−

136

C₁₀H₁₆

M

Parent compound or its isomers

138

C9H₁₄O

M + 2

 + [O] and −[CH₂]

Replacing –CH₂- group with an oxygen

150

C₁₀H₁₄O

M + 14

 + [O] and − 2[H]

Formation of C=O group from –CH₂−

152

C₁₀H₁₆O

M + 16

 + [O]

Insertion of oxygen between C and H in –CH₂− CH₂− group to form hydroxyl group, or addition of oxygen to a double bond to form epoxide group

154

C₁₀H₁₈O

M + 18

 + [O] and + 2[H]

Addition of OH and H to a double bond