cells , grown in the presence of phenylacetic acid , are incubated with phenoxymethylpenicillin ( type i ) , benzylpenicillin ( type ii ) or ampicillin and the 6-aminopenicillanic acid formed is detected and quantitatively estimated by its strong reaction with fluorescamine at ph 4 .
C0030827
benzylpenicillin
C0002680
ampicillin