FLOW-INJECTION DETERMINATION OF DIESTERS AS FERRIC HYDROXAMATE COMPLEXES

Diesters such as succinylcholine chloride (SCC) and dioctylsulfosuccin ate (DOSS) can be converted to hydroxamic acids which are found to rea ct with Fe3+ in methanol to form a purple chelate complex having an us eful absorption band at 520 nm with a molar absorptivity of about 171 L/molecm, and a detection limit of 1.5 x 10(-4) M. To adapt this meth od for flow injection, a methanol-water solvent and acidification of t he sample were required to reduce the large blank peak. The reproducib ility of the flow injection method was a factor of two better than sta ndard spectrophotometry but the detection limit of the former method w as two times higher. This colorimetric method can permit analysis of p harmaceutic al products containing either SCC or DOSS. Phosphatidylcho line (lecithin) can also be determined using this method.