Xylenol Orange Triturate

Triturate 1 part of xylenol orange with 99 parts of potassium nitrate.

Test for sensitivityTo 50 mL of water add 1 mL of dilute acetic acid, 50 mg of the xylenol orange triturate and 0.05 mL of lead nitrate solution. Add hexamethylenetetramine until the colour changes from yellow to violet-red. After addition of 0.1 mL of 0.1 M sodium edetate the colour changes to yellow.