The acetate process blank was similar when measured by GC/MS or GC/C/IRMS (36.3 vs. 49.5 nmol acetate, respectively). There was minimal blank contribution of other VFAs either at derivatisation or processing suggesting significant levels of acetate in the derivatisation reagent. Considerable variation was observed
in the derivatisation blank and hence this method of quantifying the blank was incorporated into our analytical procedure.