ASTM D6584 and DIN EN 14105 both require that the sample undergo silylation with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) to convert any residual mono- and di-glycerides into methyl esters prior to GC analysis. Because of the moisture-sensitive nature of derivatization-grade MSTFA, special precautions should be taken. It is strongly recommended to purchase and use the smallest reagent package practical for the work at hand. Storing the reagent in a tightly sealed container, such as a refrigerated desiccator, will provide the best shelf life. Carefully drying all glassware and syringes that will come into contact with the MSTFA reagent during sample preparation minimizes the opportunity for the reagent to become inactive.