Figure 2. Four new arsenolipids found in blue whiting oil.

These structures were supported by high-resolution accurate mass spectrometry, and, for arsenolipid 444, confirmed by chemical synthesis. As-HC442 and As-HC440 were proposed, by analogy, to possess the same carbon skeletons as As-HC444, but with one or two double bonds in their structures, respectively. The position and geometry of the double bonds in arsenolipids As-HC440, As-HC442 and As-HC542 were not determined; they have been assigned by analogy to commonly occurring non-arsenic lipids in organisms¹⁴.