Cacodylic acid has been widely used in buffers for electron microscopy techniques.¹It has also been used to introduce arsenic into proteins for single-wavelength anomalous diffraction (SAD) phasing in protein crystallography.²Cacodylic acid has also been used as an herbicide, acting as a defoliant.³In rats exposed to carcinogens, cacodylic acid increases the likelihood of tumor formation in the bladder, kidney, liver, and thyroid gland at concentrations as low as 50 ppm for the bladder.⁴

1.Graham, L., and Orenstein, J.M.Processing tissue and cells for transmission electron microscopy in diagnostic pathology and researchNat. Protoc.2(10)2439-2450(2007) 2.Liu, X., Zhang, H., Wang, X.J., et al.Get phases from arsenic anomalous scattering: De novo SAD phasing of two protein structures crystallized in cacodylate bufferPLoS One6(9)1-8(2011) 3.Mastradone, P.J., and Woolson, E.A.Levels of arsenical species in cotton after field application of a cacodylic acid defoliantBull. Environ. Contam. Toxicol.31(2)216-221(1983) 4.Yamamoto, S., Konishi, Y., Matsuda, T., et al.Cancer induction by an organic arsenic compound, dimethylarsinic acid (cacodylic acid), in F344/DuCrj rats after pretreatment with five carcinogensCancer Res.55(6)1271-1276(1995)