High molecular weight organic sulfur compounds

The existence of mercaptans, thiophenes, and other organic sulfur compounds in (gasifier) product gas will probably be a function of the degree of severity of the process, contacting schemes, and heat-up rate. Those processes that tend to produce tars and oils may also tend to drive off high-molecular-weight organic sulfur compounds into the raw product gas. 

Highly selective to halogenated and oxygenated compounds Electron capture detector EDB, DBCP (EPA 8011) Acrylamide (EPA 8032) Phenols (EPA 8041) Phthalates (EPA 8061) Organochlorine pesticides (EPA 8081) PCBs (EPA 8082) Nitroaromatics and cyclic ketones (EPA 8091) Haloethers (EPA 8111) Chlorinated herbicides (EPA 8151) CLP SOW for organic analysis Interferences from Elemental sulfur (S8) Waxes, lipids, other high molecular weight compounds Phthalate esters, which are common laboratory contaminants Oil in PCB analysis... 

The brief discussion above shows the difficulty of a straightforward paleoenvironmental assessment based on OSC. Their occurrence seems not to be related to any special type of environment on the contrary, they are widespread. However, several of the encountered compounds cannot be related chemotaxonomically to specific biological contributions yet, because information on the lipid composition of appropriate organisms is still scant. Nevertheless, it is clear that much information is contained in the extractable OSC, information which is not evident when only the aliphatic hydrocarbon fraction is investigated. Furthermore, high-molecular-weight sulfur species not directly amenable to GC-MS analysis is another source of information, but chemical treatment (desulfurization) is required for its disclosure. 

Kuhn-Roth method for C-methyl determination. Oxidation of organic compounds with chromic and sulfuric acids in such a manner that the C-methyl groups are converted to acetic acid which can be assayed volumetrically. The method has been modified and extended (1) to saturated fatty acids and alcohols containing up to about 20 carbon atoms, and (2) to aliphatic long-chain compounds of very high molecular weight. 

---