EDTA was used as an enhancer for Fe 2+ catalyzed light emission from luminol oxidation by dissolved oxygen. As a result, the limit of detection for ferrous ion with flow injection analysis was improved by a fact...EDTA was used as an enhancer for Fe 2+ catalyzed light emission from luminol oxidation by dissolved oxygen. As a result, the limit of detection for ferrous ion with flow injection analysis was improved by a factor of 160 by addition of EDTA to the luminol solution. Fe 2+ and Fe 3+ were determined simultaneously with a novel copper-coated zinc reductor minicolumn installed in one of the shunt after sample splitting in the manifold. The reductor minicolumn can be used for 3000 determinations at least. The dynamic range of determination was 1×10 -9 ～1×10 -5 mol·L -1 , with the limit of detection of 2.7×10 10 and 3.5×10 10 mol·L 1 ,for Fe 2+ and Fe 3+ , respectively. The preci sion for determination of 2×10 7 mol·L 1 of Fe 2+ and Fe 3+ was 2.3% and 4.0% (n=8), respectively, at a sampling rate of 60 h -1 . Cr 3+ and Co 2+ interfere. Fe 2+ and Fe 3+ in mixture were determined with satisfactory results. Samples of Fe 2+ and Fe 3+ were determined simultaneously and the results in good agreement with the standard spectrophotometric method. Indications were shown that EDTA functions as an enhancer, Fe 2+ as a catalyst, and oxygen is the oxidant of the chemiluminescent reaction, and the mechanism of the reaction was discussed.展开更多
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, F...To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, Fe（OH）x^32x and FeC6H5O7） addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3＋-EDTA, Fe^2＋-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content （30.70 mg/g biomass cell） was obtained under conditions of 18 μmol/L Fe^2＋-EDTA, despite the lower cell density （2.3×10^5 cell/ml） in such condition. Fe^3＋-EDTA is more effective than Fe^2＋-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3＋-EDTA addition. On the other hand, all the various species of iron （EDTA-Fe, Fe（OH）x^32x, FeC6H5O7） are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration （36 μmol/L） of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe（OH）x^32x and EDTA-Fe.展开更多
文摘EDTA was used as an enhancer for Fe 2+ catalyzed light emission from luminol oxidation by dissolved oxygen. As a result, the limit of detection for ferrous ion with flow injection analysis was improved by a factor of 160 by addition of EDTA to the luminol solution. Fe 2+ and Fe 3+ were determined simultaneously with a novel copper-coated zinc reductor minicolumn installed in one of the shunt after sample splitting in the manifold. The reductor minicolumn can be used for 3000 determinations at least. The dynamic range of determination was 1×10 -9 ～1×10 -5 mol·L -1 , with the limit of detection of 2.7×10 10 and 3.5×10 10 mol·L 1 ,for Fe 2+ and Fe 3+ , respectively. The preci sion for determination of 2×10 7 mol·L 1 of Fe 2+ and Fe 3+ was 2.3% and 4.0% (n=8), respectively, at a sampling rate of 60 h -1 . Cr 3+ and Co 2+ interfere. Fe 2+ and Fe 3+ in mixture were determined with satisfactory results. Samples of Fe 2+ and Fe 3+ were determined simultaneously and the results in good agreement with the standard spectrophotometric method. Indications were shown that EDTA functions as an enhancer, Fe 2+ as a catalyst, and oxygen is the oxidant of the chemiluminescent reaction, and the mechanism of the reaction was discussed.
基金Supported by Xiamen Scientific and Technologic Projects (No. 3052Z20031086)Xiamen University Alumni Association Foundation in Singaporethe First National College Students Innovative Experimental Project
文摘To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, Fe（OH）x^32x and FeC6H5O7） addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3＋-EDTA, Fe^2＋-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content （30.70 mg/g biomass cell） was obtained under conditions of 18 μmol/L Fe^2＋-EDTA, despite the lower cell density （2.3×10^5 cell/ml） in such condition. Fe^3＋-EDTA is more effective than Fe^2＋-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3＋-EDTA addition. On the other hand, all the various species of iron （EDTA-Fe, Fe（OH）x^32x, FeC6H5O7） are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration （36 μmol/L） of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe（OH）x^32x and EDTA-Fe.
