Some aroma-active sulphur volatiles are extremely potent and although producing strong aroma notes, often produce only a small sulphur PFPD peak. An example is shown in Fig. 2 for 2-methyl-3-furan thiol. At the normal attenuation this peak would generally be overlooked. It is only due to the fact that this compound produces a mid-level meaty aroma with GC–O at this retention value that further examination was warranted. Upon further expansion of the sulphur signal in this region (shown in the inset) the2-methyl-3-furanthiol peak can be observed and even then it is not well resolved.