Polychromatic shades - brick and alizarine
reds, hot oranges, lemon and chrome yellows bestirring the cool quiet colors of sky blues and forest greens - gyrate with sparkling polka dots and spirals, petals and waves, arabesques and chequerboard.
Different spectrophotometric procedures have been reported for determination of PEH including the formation of ion-pair complexes between the drug and alizarine
red S, alizarine
yellow G or quinalizarine , ninhydrin in sulfuric acid , nitrobenzene derivates in acetonitrile medium , oxidative coupling with 4-aminoantipyrine in the presence of potassium ferricyanide or sodium periodate [17,18], diazotized p-nitroaniline or 2-aminobenzothiazol in alkaline medium [19,20], forming a charge transfer complex with chloranil or haematoxylin in alkaline medium [21,22]= 7and.