Chemical Reagent Test sensitive at low concentrations
Do you have the pure compounds on hand?  If you do, the two target compounds can be crudely isolated by extracting the broth with diethyl ether, concentrating it down, and spotting on SiO2 TLC plate. Compare RF with that of the pure compounds. 
Alternatively, the same general extraction methodology could prepare a sample for GC-MS or crude NMR, if such instrumentation is available