Microglial cell line samples were carefully scraped and counted before sample preparation. Samples were analyzed for different metals including, Cd, Ca, Cr, Co, Cu, Fe, Mg, Mn, Mo, P, K, Se, Na, and Zn using ICP-MS (Analytik Jena Inc., Woburn, MA, USA) in CRI mode with hydrogen as the skimmer gas. Standards for elemental analyses were obtained from Inorganic Ventures (Christiansburg, VA), and digestion vessels, trace mineral grade nitric acid, and hydrochloric acid were obtained from Thermo Fisher Scientific (Pittsburgh, PA). Briefly, samples were digested in 70% nitric acid at 60°C for ≥12 hours. Preweighed samples were transferred to 15-ml tubes, and 0.25 ml of 70% nitric acid was added. All samples were digested overnight at 60°C. After digestion, all samples were diluted to 5 ml using 1% nitric acid with 0.5% hydrochloric acid and then analyzed using ICP-MS. For quality control, Bi, Sc, In, Li, Y, and Tb were used as internal standards for the ICP-MS.