Determination of glyceroltriheptanoate in processed animal by‐products by GC‐FID

The European Regulation concerning animal by-products (ABPs) established rules on safe use, transportation and disposal of these materials. According to the health risks, the products were sorted in three categories, and the materials belonging to category 1 and 2 (high and intermediate health risk) needed to be permanently marked in order to allow full traceability and avoid their entering in the feed and food chain. The selected marker was glyceroltriheptanoate (GTH) with a minimum permissible level of 250 mg/kg fat fraction. This study presents the implementation and validation of an analytical method for the determination of GTH in processed ABPs using GC-FID. Two injection systems (split–splitless and programmable temperature vaporization injector) and chromatographic columns were evaluated in order to select the best instrumental conditions. The method was in-house validated by assessing linearity, precision, trueness, and limit of detection (LOD) and quantification (LOQ). The linearity range was tested from 90 to 2800 mg GTH/kg, the relative SD for repeatability and intermediate precision were, respectively, 1.8 and 2.9%. The mean recovery rate was 99% and the LOD and LOQ were 6.8 and 22.8 mg/kg. In addition, the performance characteristics were compared with those of the reference method developed by the Institute for Reference Materials and Measurements (IRMM) with good agreement. A collection of real samples, obtained from different rendering plants in Italy, were subjected to analysis for the determination of GTH for routine quality controls. Practical applications: After the European Regulation (EC) 1432/2007 that established a minimum added level of GTH to processed ABPs belonging to category 1 and 2 has been put in force, a reliable and simple analytical method became necessary. The Institute for Reference Materials and Measurements (IRMM) of the European Commission developed and validated a methodology based on a GC-MS instrumentations, used by the official control laboratories. The aim of this study was the implementation of an analytical method using a GC-FID, a widespread and easy to use instrumentation. This analytical protocol found its application in the processed quality control laboratories for the routine analysis of the GTH added to ABPs, and in particular for materials belonging to category 1 and 2.