1. 0.25g indigo carmine in 100mL of 50% ethanol.
pH range 11.6 to 13.0 , colour change blue to yellow.
2. 1.0g per litre of 50% ethanol pH 11.6-14, blue to yellow.
1. 0.25g indigo carmine in 100mL of 50% ethanol.
pH range 11.6 to 13.0 , colour change blue to yellow.
2. 1.0g per litre of 50% ethanol pH 11.6-14, blue to yellow.