Non-ionic micellar solubilization — spectrofluorimetric determination of trace of germanium(IV) with quercetin in real samples

A spectrofluorometric method is described for the determination of germanium(IV) based on its complexation reaction with quercetin in presence of Brij-35. The fluorescence is monitored at 552 nm with excitation at 432 nm. The pH, quercetin and Brij-35 concentrations were optimized simultaneously using the response surface methodology from sequential experimental three-variable Doehlert designs. Interferences in this determination have been studied. The detection limit is 7.4 ng ml−1 and the linear range is between 7.4 and 150 ng ml−1. The method has been applied to the determination of germanium in a drug and in wholemeal oats. © 2001 Elsevier Science B.V. All rights reserved.