A new, simple, and rapid cloud point extraction (CPE) procedure system, combined with flame atomic absorption spectrometry (FAAS), was developed for selective separation, preconcentration, and determination of trace amounts of total iron in some environmental samples. The complexing agent, N,N -(2,2 -(ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(2-chloroacetamide) (EDBOCA), is selective at pH 5.0 for only Fe(II) and Fe(III) ions in the presence of Cu(II), Pb(II), Cd(II), Mn(II), Co(II), Cr(III), Cr(VI), Ni(II), Zn(II), Al(III), Mo(VI), Pd(II), Pt(IV), Au(III), and V(V) ions. The procedure is based on the complexation of Fe(III) ions with EDBOCA reagent in the presence of Triton X-114 (TX-114) as a non-ionic surfactant.The optimum conditions for the CPE of Fe(III) ions were investigated with respect to several experimental parameters such as pH of the solution, TX-114 and EDBOCA concentrations, incubation time and temperature, and centrifugation rate and time. The detection limit for Fe(III) ions based on the 3 times the standard deviation of the blanks ( N :10) was found to be 1.22 μ g L −1 , while the relative standard deviation (RSD) was 4.2%. Environment Canada TM-25.3 and CRM-SA-C Sandy Soil C, as certified reference materials, were used, and spike tests were applied to validate the method. The method was applied to some real environmental samples to evaluate their total iron levels.

The present study was conducted to determine the phenological changes in the content of main flavonoids, namely amentoflavone, hyperoside, isoquercitrin, quercitrin, quercetin, avicularin, rutin, (+)-catechin, and (-)-epicatechin in different tissues of Hypericum pruinatum, a promising medicinal herb of the Turkish flora. The wild-growing and greenhouse-grown plants were harvested at vegetative, floral budding, full flowering, fresh fruiting, and mature fruiting stages and dissected into stem, leaf, and reproductive tissues, which were dried separately and subsequently assayed for flavonoid contents by high performance liquid chromatography (HPLC). Chemical contents in whole plants increased during plant phenology and were similar quantitatively for both wild and greenhouse-grown plants. Depending on development stages, reproductive parts produced higher amounts of rutin, quercetin, (+)-catechin, (-)-epicatectin, and amentoflavone; however, leaves accumulated the highest level of hyperoside, isoquercitrin, quercitrin, and avicularin. The present results indicated a close relationship between flavonoid content in plant parts and phenological development of plants. It is suggested that the raw plant should be harvested during flowering for medicinal purposes.

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