Characterization of sepia ink in ancient graphic documents by capillary electrophoresis

A simple and rapid capillary electrophoresis with diode array detection method was developed for sepia ink identification in ancient graphic documents.Separation was performed in a fused-silica capillary (64.5 cm length, 50 μm i.d.). The running buffer was 20 mM sodium tetraborate solution, pH 9.2. The applied potential was 25 kV, temperature 25 °C and detection was at 220 nm. An appropriate extraction procedure was applied for the take and treatment of sample from the reference substances and ancient graphic documents. This method was successfully applied to the collection of drawings and maps from the Royal Chancellery Archives of Granada (Spain).