It has been known since the isolation of the vitamins K that derivatives of 2-methyl-1,4-naphthoquinone (MN&) are unstable to light (l-5). However, the exact nature of the chemical change is still under discussion (6, 7). An interesting observation by MacCorquodale and coworkers (3) that the vitamin is quite stable as it exists in crude extracts, only becoming labile after a fair degree of puri...
