Arsenic speciation of two specimens of Napoleon's hair

Abstract

Since 1960, it has been demonstrated by various analytical procedures that high concentrations of arsenic were present in Napoleon's hair. Various authors, indicating that the detected arsenic levels are a consequence of external contamination, have challenged the results of these examinations. We have tested two strands of hair, referenced as Noverraz and Grand Maréchal Bertrand. Samples were incubated 6h in water at 90 degrees C, and arsenic speciation was carried out by HPLC-ICP/MS. The residue was injected on a cation-exchange PRP-X200 column that allows the detection of arsenobetaine and on an anion-exchange PRP-X100 column to test for the mineral forms. In these conditions, the inorganic species As(III), As(V) and their metabolites (DMA and MMA) were separated. Analysis of hair samples highlighted massive amounts of total arsenic (42.1 and 37.4ng/mg). Arsenical species found in the two samples of analyzed hair are distributed in the following: As(III) 31.1 and 44.7%; As(V) 66.3 and 53.2%; DMA 0.42 and 0.15%. Traces of MMA were detected, and 2% of the species could not be identified. These results prove that more than 97% of the arsenic found in the hair of Napoleon is in inorganic form, which is consistent with a chronic intoxication to arsenic.