EDTA, additive

The effects of albumin, Zn2+, and Cl- are different in character and, therefore, when they are evident, they are all additive in an assay. With preparations from all sources inactivated (see Section III,3 p. 424) with (ethylenedinitrilo)tetraacetate (EDTA), addition of Zn2+ in the assay causes an immediate and complete restoration of activity. 

Modifying lead, zinc and cadmium bioavailability in soil by apatite and EDTA addition. Frese-nius Environmental Bulletin, 10, 727-730. 

Finally, it is possible to incorporate platinum particles into micelles of [ZnTOPyP]43", which has a structure similar to that of [ZnTMPyPJ44, except that one of the pyridyl nitrogen atoms is quatemized with a C,8H37 chain, making it amphiphilic, either alone or diluted with CTAC.117 Irradiation in the presence of EDTA produces hydrogen (4 = 0.004 0.002) by reductive quenching of the zinc porphyrin by EDTA. Addition of MV2+ increases the quantum yield to 0.01, either because of reduction of MV2+ by [ZnTOPyP]44 or because it is reduced by [ZnTOPyP]3+ formed by the reductive quenching by EDTA. 

EDTA addition can prevent anion interferences other than chloride, phosphate and per-oxydisulfate. 

H. Gremen, J. Persolj a, F. Lobnik, and D. Lestan, Modifying lead, zinc, and cadmium bioavailabiUty in soil by apatite and EDTA addition, Fresenius Environ. Bull, 10 (2001) 121-I m. 

The phenomenon is not observed in an acid environment (at pH levels below 2) the most stable solutions are achieved when phosphoric(V) acid at a concentration of 10 mM is used with EDTA addition. Solutions are stable for 4 days at room temperature in the presence of manganese and iron at a concentration of 100 mg Reduction in temperature to 4 °C (but without freezing) and protection from light considerably prolong the period of sample storage to 28 days after 3 months the change in the content of arsenic compounds does not exceed 10 %... 

Drinking water Sample chelation in EDTA addition of Fluron Laser-induced fluorometry 0.08 pg/L 100% at 1 pg/L Velten and Jacobs 1984 (EPA Method 908.2)... 

Drawing of air through impingers containing pH 7 phosphate buffer and EDTA addition of bisulfite, reaction of excess bisulfite with 5,5 -dithiobis(2-nitrobenzoic acid) (indirect measure of formaldehyde). 

Figure 5.9. (a) Percent nickel sorbed onto ferrihydrite as a function of pH (experimental conditions nickel lO " mol L, Fe + 0.009 mol L, NaNOs 0.1 mol L ) (Z>) EDTA sorbed (experimental conditions EDTA 10 mol L, Fe3+ 0.009 mol L , NaNOs 0.1 mol L ) (c) percent nickel and EDTA sorbed, premixed addition sequence (experimental conditions nickel I O mol L, EDTA 10 mol L, Fe + 0.009 mol L , NaNOs, 0.1 mol L, times are from contact with ferrihydrite (rf) percent nickel sorbed metal first addition sequence (experimental conditions lO mol L total nickel equilibrated with Fe + 0.009 mol L, in NaNOs 0.1 x mol L at pH l.O prior to the addition of EDTA 10 mol Measurements at 2, 26, and 50 hours indicate time elapsed since EDTA addition. (Modified from Bryce et al., 1994.)... 

Jasaitis et al. (1983) proposed a carbon electrode with covalently bound alkaline phosphatase (AP) for the determination of Zn2+. Apo-phosphatase was created by treating the electrode with EDTA. Addition of a zinc ion-containing sample restored the enzymatic activity of AP within 30 s as demonstrated by the formation of electrode-active hy-droquinone from hydroxyphenyl phosphate. After each measurement the electrode was regenerated by treatment with EDTA. As little as 0.8 pmotyl of Zn2+ could be detected. 

Bis(5-amidino-2-benzimidazolyl)methane (BABIM) (30) is a serine protease inhibitor having Ki of 19 pM (against trypsin) at pH 8.2 in the presence of 1.0mM EDTA. Addition of Zn at concentrations as low as lOOnM increased the affinity of BABIM for trypsin to Ki of 5.0 nM (i.e., by 3,800-fold). The X-ray crystal structure analysis of the trypsin-BABIM-Zn + complex (31) disclosed that His57 and Serl95 (maybe deprotonated) of trypsin, as well as two deproto-nated nitrogen atoms from each of the two benzimidazoles of BABIM, coordinate to Zn tetrahedrally in the Si (subsite 1) pocket. The BABIM in the trypsin-BABIM-Zn complex... 

Shifts relative to uncomplexed ligand (1.0 JVf in NiCU 3 Af in ligand) in parts per million. Shifts relative to uncomplexed ligand (0.5 Af Ni-EDTA) additional data NCH2CO2 = 426, 488 in parts per million. 

Ca " is an indispensable cofactor for O2 higher plant PSII Cl-33. The increased Ca has been attributed to release of Ca " ", although the role 5f still unclear Cl-4]. In this study, we report a unique property of the S2 state generated in spinach PSII stringently treated with NaCl under illumination followed by EDTA addition. 

Polarography has been helpful and almost the only tool to study these rearrangements in aqueous solution. The similarity between curves measured for both binuclear complexes (Fig. 1) is obvious and the absence of polaro-graphic waves in this area for the mononuclear complex indicates a high reduction potential (2). The appearance of two waves for the binuclear complexes is explained by dissociation of the water molecules attached to metal in each case, which is higher for the mote basic solution of the mixed chelate and low for the mote acidic solution of the distannous EDTA. Addition of basic or neutral electrolytes has no effect on the polarogram of disodium tin (II)-EDTA, however, acid produces a dramatic change as shown in Table 111. 

Some conclusions can be drawn about the interaction of the iron-on-zirconia catalysts. In catalysts containing only iron, it is observed that while the first onset of reduction is equal in all samples, complete reduction is retarded in the catalysts prepared using the Engelhard support and with EDTA. Addition of potassium shifts the onset temperature of the initial reduction to temperatures about 100°C higher than in catalysts without potassium. This effect has been observed before [3]. 

Fig. 2 - Unfolding spectra for the subunits and their RNAs. They represent the changes in the absorption spectra on Mg " removal. The solvent was 10 mM Tris-HCl (pH 7.4) with 0.08 mM Mg-acetate magnesium removal was accomplished by EDTA addition to a concentration of 0.2 mM.

Fluorimetric determination of the complex after EDTA addition... 

Apparently (see Table 16) the addition of EDTA leads to correct results on both commercial columns specially designed for hop acids analysis. It must be noted that EDTA has to be added to the water used for preparing the eluent. In the eluent itself it is very difficult to dissolve the indicated amount of EDTA. This is the reason why EDTA addition failed many years ago, when we first tried this. According to the Merck Index 1 litre of water can dissolve 500 mg of EDTA. Still, to dissolve 100 mg of EDTA in 300 ml of water may take considerable time. The disodium salt of EDTA is more soluble, but although results with this chemical were reasonable, EDTA seems to be better. With the disodium salt of EDTA, larger amounts were tried, but this did not further improve the results. It is noteworthy that the standard deviation (s%) in the tables becomes smaller with every improvement of the analytical results due to changes in eluent composition. 

Some further results, presented in Table 17 show that columns which are not specifically designed for iso-alpha acids analysis are unsatisfactory, even with EDTA addition to the eluent. 

Table 17. A eluent as mentioned in the text. B Idem as A but with the disodium salt of EDTA. C idem as A but without EDTA. On non-demineralized RoSil (last column) the iso-alpha acids peak shape is very bad, also with EDTA addition. Without EDTA addition even the Rosil (Hop) and Nucleosil (Hop) columns do not give correct results.

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