The reaction of N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide with arginine proceeds with cleavage of the guanidino group, producing a mixture of the tert-butyldimethylsilyl derivatives of ornithine and carbodiimide. These compounds are identified by analysing the reaction mixture using gas chromatography/mass spectrometry. The reaction of N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide with arginine proceeds with cleavage of the guanidino group, producing a mixture of the tert-butyldimethylsilyl derivatives of ornithine and carbodiimide. These compounds are identified by analysing the reaction mixture using gas chromatography/mass spectrometry.