Table 2.

Characterization of inorganic and organic arsenic species

Compound	m/z	Elemental formula
As(V)	109	[AsH2O2]+
	143	[AsH3O4 + H]+ Protonated As(V) molecular ion
	161	[AsH6O5]+
As(III)	109	[AsH2O2]+
	143	[AsH3O4 + H]+
	161	[AsH6O5]+
MMA	109	[AsH2O2]+
	141	[CAsH5O3 + H]+ Protonated MMA molecular ion
	143	[AsH3O4 + H]+
	161	[AsH6O5]+
DMA	109	[AsH2O2]+
	139	[C2AsH7O2 + H]+ Protonated DMA molecular ion
	141	[CAsH5O3 + H]+
	143	[AsH3O4 + H]+
	161	[AsH6O5]+
AsBet	105	[C2AsH6]+
	109	[AsH2O2]+
	120	[C3AsH9]+
	135	[C2AsH4O2]+
	139	[C2AsH7O2 + H]+
	141	[CAsH5O3 + H]+
	143	[AsH3O4 + H]+
	161	[AsH6O5]+
		[C5AsH10O]+
	179	[C5AsH11O2 + H]+ Protonated AsBet molecular ion