1991), or more frequently interpreted as analytical artefacts because of evidence of their formation during pyrolysis of aliphatic compounds through cyclisation and aromatisation (Saiz-Jimenez 1994/?).
In sample S2, KMn[O.sub.4] oxidation (MN-2) (with a smaller decrease of OC, 1.3 mg [g.sup.-1]) caused a strong decline in carbohydrate products (from 31.5% of TQPA in NO-2 to 17.4% in MN-2) and an increase in aliphatic pyrolysis products (sum of n-alkanes, n-alkenes and other aliphatic compounds from 5.3% in NO-2 to 23.1% in MN-2).
Total; >[C.sub.18], long/chain n-alkenes/alkanes; [C.sub.18]/[C.sub.10], short/cham H-alkenes/alkanes; OA, other aliphatic compounds (predominantly branched alkenes); Ph, phenols; TL, total lignin markers; MAH monocyclic aromatic hydrocarbons; AB, alkyl/benzenes; PAH, polycyclic aromatic hydrocarbons (intact terpene/like plant biomass, ITPB; black/carbon/derived, BC); N, nitrogen compounds; BN, BC/derived N compounds; Polysacchs, polysaccharides (well preserved, WP; degraded, Dg); U, unidentified compounds; B/ AB, benzene/alkyl-benzenes ratio; P/AP, total PAH/alkylated PAH ratio Second row: relative proportions within main group (n-alkanes/enes, MAHs, PAHs, N compounds and polysaccharides).
Use of this hydrophobicity index may improve prediction of water repellency from soil properties, as it is a direct measure of the proportion of C in the soil present as aliphatic compounds which cause water repellency.
Infrared microscopy can be used to identify hydrophobic aliphatic compounds in the coating on a single sand grain.
It is not possible (according to the available knowledge) to eliminate the formation of PAH in the obtained oil without elimination or decreasing the aromatization processes via secondary reactions through either a Diels-Alder type reaction or selective cracking of aliphatic compounds resulting in selective concentration of aromatic compounds.
* The formation of aromatics via secondary reactions during pyrolysis has been attributed to Diels-Alder type reactions or to gas-phase cracking of aliphatic compounds resulting in selective concentration of aromatic compounds.