ABSTRACT
Solvent extraction of microamounts of Eu3+ and Am3+ from water into nitrobenzene by means of a mixture of hydrogen dicarbollylcobaltate (H+B-) and N,N,N',N'-tetrabutyl-1,10-phenanthroline-2,9-dicarboxamide (L) was studied. The equilibrium data were explained assuming that the species HL+, H2L2+, HL+2, ML3+2, and ML3+3 (M3+ = Eu3+, Am3+; L = N,N,N',N'-tetrabutyl-1,10-phenanthroline-2,9-dicarboxamide) are extracted into the nitrobenzene phase. Extraction and stability constants of the cationic complex species in nitrobenzene saturated with water were determined and discussed. From the experimental results it is evident that this effective N,N,N',N'-tetrabutyl-1,10-phenanthroline-2,9-dicarboxamide receptor for the Eu3+ and Am3+ cations could be considered as a potential extraction agent for nuclear waste treatment.
ABSTRACT
A mesofluidic platform (MP) with fluorescence detection based on a stepwise injection analysis (SWIA) was used for the determination of curcumin in biologically active supplements and food spices. The main units of the MP are a mixing chamber (MC) and an optical channel with a quartz capillary inside. The MC provides rapid and complete mixing solutions by gas bubbling. The proposed method is based on the new rapid and sensitive reaction of curcumin with a fluorescence reagent - 4-(2,3,3-trimethyl-3H-indolium-1-yl)butane-1-sulfonate (TIBS). The fluorescence intensity of TIBS is greatly quenched in the presence of curcumin in an alkaline medium. The linear range was from 1 to 10µM of curcumin, and the limit of detection, calculated as 3σ of a blank test (n=5), was found to be 0.3µM. The sample throughput was 24h(-1). The proposed method was successfully applied for the determination of curcumin in biologically active supplements and samples of food spices. The obtained data were in good agreement with those measured by a HPLC-UV method.
