Determination of MOSH and MOAH - German standard method with improved precision data

Abstract

Mineral oil hydrocarbons (MOH) are divided into the group of mineral oil saturated hydrocarbons (MOSH) and of mineral oil aromatic hydrocarbons (MOAH). MOH are often found at higher levels in edible oils than in most other foods. According to current knowledge, the sources of contamination are distributed along the entire production chain. Therefore, a systematic investigation of these sources and their contribution to the overall contamination is necessary in order to develop and implement appropriate minimization options. This minimization was a great challenge for manufacturers as results from different laboratories often showed limited comparability using the actual European standard method EN16995:2017 especially in the lower concentration range below 10 mg/kg. To overcome this problem an improved method with a lower limit of quantification at 1 mg/kg was developed and published as a German standard method DGF C-VI 22 (20) “Mineral oil saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH) with online coupled LC-GC-FID-method for low limit of quantification.” Precision data of total MOSH and MOAH and of fractions according to the advice of the Joint Research Center was successfully determined in a collaborative trial on different edible oil matrices with a group of 14 experienced laboratories from Germany, Austria and Italy. The collaborative trial was evaluated according to ISO 5725. Total MOSH ranged from 2 mg/kg to 99 mg/kg and total MOAH from 1 mg/kg to 31 mg/kg. Good reproducible relative standard deviations of 12.5 %–20.7 % as well as Horrat values ranging between 1.1 and 2.3 have been achieved for total MOSH. The reproducible relative standard deviation of total MOAH ranged from 12.4 % to 39.5 % with Horrat values between 0.9 to 2.6.