Determination of manganese in human brain samples

A method is presented for the determination of manganese (Mn) in human tissue samples (especially brain) by graphite furnace atomic absorption spectrophotometry (GFAAS). After complete digestion by a mixture of concentrated nitric acid (HNO₃)/concentrated perchloric acid (HClO₄) (50:50, v/v), the samples are assayed on a Perkin-Elmer 5100 PC apparatus, equipped with transversal graphite tubes and a Mn-specific hollow cathode lamp. The furnace conditions are as follows (for each step: temperature (°C)/ramp (s)/duration (s)) dry 120/1/40; char 1200/5/10; atomization 2250/0/4; pyrolysis 2400/1/1. Zeeman correction is employed. The method is linear over the range 0.05 to 5.00 μg/g wet tissue, and the limit of detection for Mn is about 0.01 μg/g wet tissue. This simple and rapid method may be of value for the post-mortem assessment of Mn accumulation in brain structures due to occupational or iatrogenic exposure. An application is presented in which elevated levels of Mn were determined in the brain samples of a 63-year-old female deceased after long-term total parenteral nutrition involving Mn supplementation.