Amyl alcohol (normal only) 75 ml HCl (concentrated) 25 ml
Dissolve p-dimethylaminobenzaldehyde in normal amyl alcohol. Slowly add HCl. Store at 4°C. To test for indole, add 0.2-0.3 ml reagent to 5 ml of 24 h bacteria culture in tryptone broth. Dark red color in surface layer is positive test for indole.
R34. 0.1 N Lithium Hydroxide Lithium hydroxide (anhydrous) 2.395 g Distilled water 1 liter
R35. Lugol's Iodine Solution Potassium iodide (KI)10 g Iodine 5 g Distilled water 100 ml
Dissolve KI in about 20-30 ml of distilled water. Add iodine and heat gently with constant mixing until iodine is dissolved. Dilute to 100 ml with distilled water. Store in amber glass-stoppered bottle in the dark.
R36. Methyl Red Indicator Methyl red 0.10 g Ethanol, 95% 300 ml Distilled water to make 500 ml
Dissolve methyl red in 300 ml ethanol. Bring volume to 500 ml with distilled water.