Use of glyceroltriheptanoate as marker for processed animal by-products: development and validation of an analytical method.

A recently published European Regulation requires that the artificial marker, glycerol triheptanoate (GTH), be added to processed animal by-product (ABPs) prohibited from entering the food chain. The objective of this new requirement is to allow full traceability and ensure that these materials are disposed of in a proper way. Here, we report the development and single-laboratory validation of an analytical method for the determination of GTH in meat and bone meal plus animal fat. The method comprises three steps: (1) extraction of GTH from the samples with petroleum ether when analysing meat and bone meal or dissolving the sample in n-hexane when analysing fat; (2) clean-up of the extract using commercially available SPE cartridges; (3) determination of GTH by GC/MS or GC with flame ionisation detection (FID). The results of the validation study demonstrated that the relative standard for intermediate precision varied between 2.5 and 8.2%, depending on GTH concentration and the detector utilised. In all cases, the relative recovery rate was above 96%. The limit of quantification was 16 mg kg(-1) (GTH/fat content of the sample) with MS as detector and 20 mg kg(-1) with FID. Moreover, the method has been successfully applied in a second laboratory, indicating its transferability. Considering the minimum GTH concentration in ABPs of 250 mg kg(-1), the method is considered suitable for the intended purpose and can be utilised by EU Member States laboratories for official control and monitoring.