Identification of synthetic dyes in early colour photographs using capillary electrophoresis and electrospray ionisation-mass spectrometry.

Capillary electrophoresis with photodiode array detection (CE-PDA) and with electrospray ionisation-mass spectrometry (CE-ESI-MS) was used for the separation and the identification of 23 synthetic organic dyes, among those used in early 20th century colour photographs such as autochromes. Both cationic and anionic dyes could be separated within 15min using a single CE-PDA method. The method was used as the basis to develop a CE-ESI-MS methodology through the optimisation of the relevant ESI and MS parameters.

Simultaneous identification of natural dyes in the collection of drawings and maps from The Royal Chancellery Archives in Granada (Spain) by CE.

A simple and rapid capillary electrophoretic method with UV detection (CE-UV) has been developed for the identification of five natural dyes namely, carmine, indigo, saffron, gamboge and Rubia tinctoria root. The separation was performed in a fused-silica capillary of 64.5 cm length and 50 microm id.

Sampling and identification of natural dyes in historical maps and drawings by liquid chromatography with diode-array detection.

A simple and rapid liquid chromatographic with diode-array UV-vis spectrophotometric detection (HPLC-DAD) method for identification of natural dyes has been developed. Chromatographic retention of carminic acid, indigotin, crocetin, gambogic acid, alizarin and purpurin has been studied. The mobile phase consisted of 40 mM SDS-10 mM phosphate buffer solution (pH 2.