Quantitative mass spectrometry is often performed using isotopically labeled samples. Although the 4-trimethylammoniumbutyryl (TMAB) labels have many advantages over other isotopic tags, only two forms have previously been synthesized (ie, a heavy form containing nine deuteriums and a light form without deuterium). In the present report, two additional forms containing three and six deuteriums have been synthesized and tested. These ...
