Possibilities of detection residue of mineral oil in sunflower oil | Možnosti detekcie rezíduí ropných látok v slnečnicovom oleji

It is not first time we eat mineral oil material. Mineral oil is the largest contamination of our body. Products of mineral oil are everywhere around us. Food can be contaminated during production from machine (vaseline, hydraulic oil.) or from packing (wax paper) or during transport (motor oil, tarmac). The analytical target is the determination of mineral oil material in sunflower oil. Present analytical methods only enable the detection of the paraffins (saturated alkanes), but not of the (usually highly alkylated) aromatics (which make up roughly 30% of the mineral oil). Mineral paraffins (alkanes of mineral oil origin) must be distinguished from paraffins of plant origin. Plant paraffins primarily consist of n-alkanes and are characterized by the predominance of the odd-numbered species (usually C27, C29, C31 and C33). Mineral paraffins primarily consist of branched or cyclic species (in GC forming a hump of unresolved material), possibly with n-alkanes on top with even and odd numbered species being balanced. Sample preparation included a pre-separation step whereby only saturated hydrocarbons remain in the sample matrix to analyse used of a silica gel column for sample clean-up. Detection method is preferably GC-FID (flame ionisation detector). Calibration by an alkane or paraffin oil assuming equal response of all paraffins. Analytical results reflected only the presence of saturated hydrocarbons in the range of c10-c56 from external sources (the endogenous presence of hydrocarbons has not to be reported, in the case of sunflower oil, the alkanes C27, C29 and C31 are considered to be of endogenous origin). Acceptable level of saturated hydrocarbons (mineral oil) from external sources in crude sunflower oil is 50 ppm. Acceptable level of saturated hydrocarbons (mineral oil) from external sources in refined sunflower oil is 50 ppm. State veterinary and food institute (SVFI) in Dolný Kubín uses for determination of mineral oil in sunflower oil kattel method from 2008. Sample is clean up using activated silica gel packed in glass tube. Clean extract is injected using on-column injection on non polar fused silica capillary column and pollutants are detected by FID. Quantification of mineral oil is done using of relative ratio of peaks area of hump to internal standard C16. During year 2008 were investigated 42 official samples of sunflower oils from market or border control. Country of origin (48% Ukraine, 23% Hungary, 48% Slovakia, 5% Czech republic, 5% Germany). One sample has contained mineral oil in relative high concentration (650 mg/kg) what was over of acceptable level (50 mg/kg). Three samples contained mineral oils close to acceptable level. All positive samples were from Ukraine. Due to know relative high contamination of mineral oil around us systematic random control of food is needed.