This paper provides high-resolution chemistry and impurity measurements from the Mount Brown South ice core in East Antarctica, from 873 to 2008 CE. Measurements include sodium, ammonium, hydrogen peroxide, electrolytic conductivity, and insoluble microparticles. Data are provided on three scales: 1 mm and 3 cm averaged depth resolution and decadally averaged. The paper also describes the continuous flow analysis systems used to collect the data and characterizes uncertainties and data quality.