Several procedures involving gas chromatography (CC) have been described for the analysis of phenylurea herbicides. Earlier methods were based cm the hydroiysis af pfienyiureas followed by GC of the correspond&g anilines, either di_z~.Aly~-~ or as derivatives~-5. The transformation Into &tines has the disadvantage that specific deterz&ation of such phenyhxeas as lil~urori and d&on, which contaiin the same substituted-pheny: moiety, is not possible withont previous and timeconxxning separation. 1~ order to overcome this problem, attempts have been made to perform &ect GC of pheqlurez&'.
However, SpengIer and Hamroll& have p&ted ~rrt +&at pherqlureas anaIysed as described by McKone and Hance6 are pyrolysed and eiuted as pbeoyl isocyzmates. According to Katz and Strusz', this decomposition was msrkedfy reduced by temperature-programmed GC after aging of the cohmm with a mixture of the compounds urider st;Gdy. Hawever, retention times could not be reproduced, so that the procedure is not applicable for identifying unknown phenylureas.
This paper elucidates the therm& instability of phexylurea compounds and describes rhe X-meehyladon of mono-, di-arzd trisxbstitrrred phenyIureas by the use of eodkm hydride, dime+JryE s=JIphoxide and iodomethane-Procedures for the GC separation and GC-mass spectrometic (MS) iderLtifx&ion of the tetra-subs&u&d derivatives are suggested. h&&y, the camporrnds Iisted in Tabfe I were investigated by GC-MS. This