The dataset contains chromatographic traces of samples containing thioarsenic species and solubility data for disordered orpiment (arsenic sulfide). This dataset is associated with the following publication: Wilkin, R.T., R.G. Ford, L.M. Costantino, R.R. Ross, D.G. Beak, and K.G. Scheckel. Thioarsenite Detection and Implications for Arsenic Transport in Groundwater. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 53(20): 11684-11693, (2019).