3-MCPD (3 monochlorpropandiol) belongs to the chemical group of the so-called chlorpropanols. These are formed as by-products of processing foodstuffs from natural constituents (food-borne toxicants). The lead substance 3-MCPD is formed when foodstuffs containing fat and salts are exposed to high temperatures.
In 2002, the German Federal Institute for Risk Assessment (BfR) classified 3-MCPD as an unsafe substance from a toxicological point of view. Directive (EC) 466/2001 (Directive on Maximum Amount of Contaminants) currently sets a maximum content of 20 µg/kg for soya sauce and hydrolysed vegetable protein (HVP). At the moment, no maximum 3-MCPD ester content for foodstuffs has been specified.
To analyse 3-MCPD esters, first of all the fat is extracted from the sample. The 3-MCPD ester contained is then saponified and the 3-MCPD released. Through derivatising with phenylboronic acid, a highly voluble reaction product results, which is then extracted with hexane and quantified using GC/MS. Quantification is by the method in our internal standards. To do this, isotope-labelled 3-MCPD-d5 is added before extraction.
Fig 2: Chromatogram of a standard 20 mg/kg, SIM traces of the 3-MCPD (left, m/Q 196/147/146)
and of the internal standard 3-MCPD-d5 (right, m/Q 201)