Analysis of Oils
Examples of vegetable oils rich in monounsaturated
fatty acids are olive oil, rape oil and peanut oil.
These also contain high amounts of oleic acid.
Examples of oils rich in polyunsaturated fatty acids
are safflower oil, sunflower oil, soybean oil, corn oil and
cottonseed oil.
Long term storage of untreated oils is a problem as they
can go rancid rather quickly. The more unsaturated
fatty acid they contain, the quicker they go rancid. The primary
cause of rancidity is exposure to oxygen resulting in oxidation
of oils.
Antioxidants prevent fats and oils from
being oxidized and prolong therefore the shelf life. Edible
oils contain some natural tocopherols (vitamin E) as an antioxidant.
Legally permitted food additives acting as antioxidants are
vitamin C (ascorbic acid) or the more lipophilic ascorbylpalmitate
as well as additional vitamin E or BHT (butylated hydroxytoluene)
or BHA (butylated hydroxyanisole).
Metrohm has a variety of methods and instrumentation
for the determination of the quality of oils at hand.
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Food
Analysis 
