Anewformulawaspresentedforlocatingdoublebondpositionindodecenols,tetrade-cenols,hexadecenolsandtheiracetates,basedonmassspectraldataofdimethyldisulfidederivatives.Inthisprocedure,molecularionandbasepeakionwereutilizedascharacteristicparameterstoidentifythepositionalisomers.Themethodwastestedwithmassspectraof25dimethyldisulfldederivativesofmono-unsaturatedacetatesandalcohols,andtheoriginaldouble-bondpositionineachisomerwaslocatedunambiguously.