Interlaboratory evaluation of injection techniques for triglyceride analysis of cocoa butter by capillary gas chromatography

As part of two international collaborative studies, in which 14 laboratories applied capillary GLC to determine the triglyceride (TG) profile of cocoa butter, the performance of different sample introduction techniques, i.e. cold on-column injection (OCI), split injection and programmed-temperature vapouriser (PTV) injection, was compared. In both studies, the participants did not apply a uniform GLC procedure. Synthetic mixtures of triglycerides were chosen to permit an accurate determination of detector response factors. No statistically significant difference was found between the mean values obtained by different injection modes. The OCI, generally recommended as best practice, did not give superior results than the PTV or the split injection techniques.