GC-MS Analysis of Cocoa Butter Triglycerides
Cocoa butter is the edible fat extracted from cocoa beans that is used in the manufacture of chocolate. Cocoa Butter Equivalents (CBE) are a substance derived from palm oil and shea butter that are used as a substitute for cocoa butter in chocolate. European regulations govern the labeling of chocolate as containing CBE less than 5%. US regulations require that Cocoa Butter Equivalents be specifically labeled with wording such as “chocolate flavored” coating. Analysis of the triglyceride content of chocolate is a quality control measure. Analysis of a standard sample of cocoa butter triglycerides is presented here as an example of the use of the JEOL Q1500 quadrupole GC-MS system for the detection of lipids separated by using a high-temperature GC column (Restek Rtx-65TG).
A certified cocoa butter reference standard (IRMM-801) was purchased from LGC and prepared as a solution in isooctane according to the directions supplied with the standard. A Restek Rtx-65TG high-temperature GC column was installed in the Agilent 7890B gas chromatograph with a 1 m deactivated fused silica guard column, and the column was directed into the JEOL MS-Q1500GC quadrupole mass spectrometer for analysis. The GC conditions (Table 1) were adapted from the European standard for the analysis of Cocoa Butter Equivalents (https://ec.europa.eu/jrc/sites/jrcsh/files/EUR%2020831%20EN.pdf). One microliter of sample was introduced into the gas chromatograph as a split injection using a 10:1 split. The low split ratio causes a modest amount of overloading for the high-abundance components, but was used to make it easier to detect the low-level triglycerides in the total ion current chromatogram. Mass spectra were acquired in scan mode using the conditions shown in Table 2.