FIG. 3.

Structures of the phosphoryl moieties that have become attached through phosphorus to tyrosine. Covalent binding to tyrosine results in loss of the fluoride ion from soman, DFP, FP-biotin, and sarin, of the dichlorovinyl alcohol group from dichlorvos, and of the trichloropyridinol group from chlorpyrifos oxon. Tyrosine loses one hydrogen. The added mass is 162.2 for soman, 164.1 for DFP, 136.0 for chlorpyrifos oxon, 572.3 for FP-biotin, 108.0 for dichlorvos, and 120.0 for sarin. The arrows in FP-biotin indicate fragmentation sites. A 227 amu ion is produced by cleavage between carbon 16 and the adjacent nitrogen. A 329 amu ion is produced by cleavage between carbon 10 and the adjacent nitrogen. The 312 amu ion is produced by loss of the amine from the 329 ion.