Sentence:  He was obsessed with making LSD even purer than Sandoz, producing it first in powder form in gelatin capsules as well as light-blue liquid (“Mother's Milk”) that was easily recognizable when <WSD>titrated</WSD> onto sugar cubes. 
Meaning of the word marked with <WSD> tags:  To ascertain the amount of a constituent in a solution (or other mixture) by measuring the volume of a known concentration (the "standard solution") needed to complete a reaction.