The addition of an acid (usually nitric or sulfuric) to a sample to lower the pH below 2.0. The purpose of acidification is to "fix" a sample so it won't change until it is analyzed.
ACIDIFIED (UH-SID-UH-FIE-D)
Meaning of ACIDIFIED (UH-SID-UH-FIE-D) in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012