Dr Heinrich Mannebeck, the German pioneer of olfactometry, died at 86 on 29 Dec. 2022. As an agriculture scientist, he started in 1976 with a simple olfactometric device to take ambient indoor and outdoor samples of clearly noticeable concentrations. Then, 20 years later, he founded the company Ecoma with his children Dorothee and Dietmar Mannebeck. This company was initially based in Kiel, but 2 years later was moved to  a detached house between farms and apple trees in the little town of Honigsee.

  In the 1970s, the urban exodus began in Germany. Many moved to the countryside with their families. At first, they still found the smell of manure, animals and stables pleasant, but at some point, it became annoying. More and more complaints came across the desk of Dr Heinrich Mannebeck, a member of staff at the Institute of Agricultural Process Engineering at Christian Albrechts University in Kiel. But there were no methods of measuring odour at that time.

   Nalophan bags are commonly used for air sampling and especially for odour analysis. Even if olfactometric measurement must be carried out within maximum 30 hours after sampling, the question of potential sample evolution is always present. This study illustrates the behaviour of selected sulphur compounds in Nalophan bags from filling to analysis (over a period up to 100 hours).

   Select compounds were hydrogen sulphide, carbon disulphide, methyl mercaptan, ethyl mercaptan, dimethyl sulphide, diethyl sulphide and dimethyl disulphide and tested at high concentration level (in a range of 3900 to 1800 ppb each) to facilitate their direct and quick measurement by gas chromatography with flame photometric detector. The chemical analysis shows losses by adsorption and by diffusion depending on time and other conditions. Even if the variation seems limited during the first hours, the evolution shows that the need for a better film is real.