Maurus Biedermann

Food contamination by hydrocarbons from lubricating oils and release agents : determination by coupled LC-GC

We have found that many foods are contaminated with mineral oil products used as lubricating oils/greases or as release agents. The mineral oil base of such products usually consists of branched alkanes ranging between C17 and C35. It forms a broad hump of unresolved compounds in the gas chromatogram. Examples of such products are described; contamination is shown for a sample of bread, bonbon, and chocolate, respectively. The results suggest that contamination of foodstuffs with mineral oils does not always receive the required attention. However, there is also a lack of guidelines.

Determination of organophosphorus insecticides in edible oils and fats by splitless injection of the oil into a gas chromatograph (injector-internal headspace analysis)

ZusammenfassungDirekte Einspritzung von Öl oder Fett in einen mäßig heißen Injektor des Gaschromatographen erlaubt eine Art Headspacetechnik im Verdampfungsinjektor: Öl oder Fett wird 1∶1 mit Aceton verdünnt und bei 200 °C eingespritzt. Die Komponenten, z. B. Phosphorsäureester-Insektizide, verdampfen aus dem Ölfilm auf der Röhrchenwand und werden splitlos in die Säule übertragen. Das Öl fließt langsam der Wand entlang nach unten und wird in einer Art Tasche aufgefangen. Mit flammenphotometrischer Detektion liegt die Nachweisgrenze unter 10 μg/kg.AbstractDirect injection of oil or fat into a moderately heated injector enables performance of a kind of head-space technique in, the injector: oil or fat is diluted 1∶1 with acetone and injected into a vaporizing chamber at 200° C. Components, for example organophosphorus insecticides, evaporate from the oil film on the insert wall and are transferred into the column in the splitless mode; the oil slowly flows along the wall to the bottom of the insert and is retained there in a kind of a bag. Using a flame photometric detector, detection limits are below 10 μg/kg.