ABSTRACT
This technique has been applied exclusively to organic and organometallic compounds with no applications to the determination of anions and cations.
14.1 Organic compounds
14.1.1.1 P e t r o l e u m spil ls
Thin layer chromatography has replaced paper chromatography in many applications because of its greater versatility and reproducibility. It has been applied as a rapid method of classifying petroleum and natural and synthetic oils by chromatographic O.lmg quantities of sample oils [1]. These were spotted on to a silica gel plate and developed with an ascending solvent composed of 70:30 vol/vol chloroform-benzene. After l h the solvent was evaporated, and the resulting chromatogram evaluated in ultraviolet light (366nm) and the fluorescent areas noted. This was followed by spraying the chromatogram with concentrated sulphuric acid and baking it at 120°C for 15min. Coloured zones formed under visible and ultraviolet light were noted. With this procedure, oils were classified into four groups:
1 hydrocarbon oils (eg petroleum products); 2 synthetic ester oils; 3 naturally occurring oils; 4 oils of different composition (eg silicone oil and low-molecular-weight
polyethylene oxides).
