Speciality chemicals group Johnson Matthey said its underlying performance for the full year is expected to be slightly ahead of previous company expectations after third quarter profit rose by 34%. The third quarter performance was driven as demand in its key markets remained robust, the group said in a company statement. Sales excluding precious metals were up 22% of the same period last year and slightly up on the second quarter of this year. Operational leverage and higher precious metal prices resulted in underlying operating profit rising 31% on the same quarter the year before.Profit ay Johnson Matthey's environmental technologies business rose 14% while its fine chemicals unit delivered only slight growth, the group said.