Identification of degradation products of phenylarsonic acid and o-arsanilic acid in contact with suspensions of soils of volcanic origin

► Several organoarsenicals of phenylarsenicals in contact with soil were identified. ► Combining HPLC with different MS detection led to a structural elucidation. ► Nitrophenylarsonic and methylphenylarsinic acid were identified as products. ► Isomers of hydroxyphenylarsonic acid were observed after irradiation with visible light.