1, 8-Dihydroxyanthraquinone As A Reagent For Boric Acid And Its Use In The Analysis Of Pharmaceutical Grade Glass.

Various anthraquinone derivatives are known to give a very sensitive colour reaction with boric acid, identification limit being 1 ug of boron with purpurin 0.6ug for alizarin S and 0/06ug for quinalizarin, but the intensity was not proportional to the concentration. The reagent 1, 8-dihydroxyanthraquinone (istizin, Chrysazin) was found to be almost as sensitive as quinalizarin and reacted to give a complex colour with two maximum absorbancies at 340 and 580 mu (beer's law is not obeyed) but by the use of a calibration graph the latter wavelength could be utilised for a spectrophotometric method.