EDTA concentration

EDTA concentration and the degree of inhibition (Shimomura et al., 1961). In a 30 mM sodium phosphate buffer containing 60 mM NaCl, pH 7.0, inhibition by EDTA is very strong (84%) even at an EDTA concentration as low as 25 pM, but the inhibition does not increase beyond 90% even at an EDTA concentration of 5 mM. The inhibition is completely reversed by the addition of a sufficient amount of Ca2+ to bind EDTA. 

Classical approaches to plant DNA isolation aim to produce large quantities of highly purified DNA. However, smaller quantities of crudely extracted plant DNA are often acceptable for PCR analysis. Another efficient method for preparation of plant DNA for PCR is a single-step protocol that involves heating a small amount of plant tissue in a simple solution. Several factors influence nucleic acid release from tissue salt, EDTA, pH, incubation time and temperature. These factors must be optimized for different sample substrates. EDTA in the sample solution binds the Mg + cofactor required by the Taq polymerase in the PCR, so the EDTA concentration in the solution, or the Mg + concentration in the PCR, must be carefully optimized. 

Anions of weak acids can be problematic for detection in suppressed IEC because weak ionization results in low conductivity and poor sensitivity. Converting such acids back to the sodium salt form may overcome this limitation. Caliamanis et al. have described the use of a second micromembrane suppressor to do this, and have applied the approach to the boric acid/sodium borate system, using sodium salt solutions of EDTA.88 Varying the pH and EDTA concentration allowed optimal detection. Another approach for analysis of weak acids is indirect suppressed conductivity IEC, which chemically separates high- and low-conductance analytes. This technique has potential for detection of weak mono- and dianions as well as amino acids.89 As an alternative to conductivity detection, ultraviolet and fluorescence derivatization reagents have been explored 90 this approach offers a means of enhancing sensitivity (typically into the low femtomoles range) as well as selectivity. 

The Pu +/Pu + couple for a series of Pu(IV)/(EDTA ) based complexes, where EDTA = ethylenediaminetetraacetate, has been studied as a function of pH and EDTA concentration [118]. The voltammetry was also studied with citrate and carbonate ions present in solution. At a relatively low pH of 2.3 and equimolar Pu +/EDTA concentrations a quasi-reversible one-electron reduction is observed for Pu(EDTA) at E /2 = 0.342 V versus SHE. The quasireversibility of this process remains as the pH is raised to 4.6. Additional voltammetry studies are discussed in the paper for the higher coordinate Pu + species, Pu(EDTA)-L (where L = EDTA, carbonate, citrato), all of which show irreversible electron-transfer behavior. 

The influence of Na+, K+, calcite, and EDTA on complete hydroxyapatite dissolution and hydroxypyromorphite formation was also examined (Ma 1996). Only high EDTA concentrations (EDTA/Pb molar ratios up to 5) significantly affected the ability of dissolving hydroxyapatite from sequestering hydroxypyromorphite the strong bond between the EDTA ligand and the Pb2+ was fairly competitive with the tendency to precipitate out as hydroxypyromorphite. 

Thus, if is large enough, for a given solubility product Ksp, and the pH and free EDTA concentration are appropriate, the solid M(OH)m of reaction 13.13 will pass entirely into solution (see Exercise 13.6). Since the donor atoms in these ligands are hard oxygen, they are particularly effective against hard Mm+ ions such as Ca2+ or Fe3+. 

Spreadsheet equation for auxiliary compiexing agent. Consider the titration of metal M (concentration = Cm, initial volume = Vm) with a solution of EDTA (concentration = CEDTA, volume added = VEDta) n the presence of an auxiliary compiexing ligand (such as... 

Figure 10. Rate of 2-butanol formation at different time intervals of illumination. Initial (NHi+ EDTA concentration 2xlO 2M. a) Addition of (NH4)3EDTA, 2xlO-2M, b) and c) Addition of (NHit)3EDTA, 1.7x10 2M.

Inspection of individual test runs showed that the strontium spike, corresponding to 3xl0 3M total strontium, dissolved entirely when HEDTA or EDTA concentrations were 0.1M or 0.05M, respectively. However, in the presence of 10 5M or lower HEDTA or EDTA concentrations, strontium was at saturation with concentrations of about 4xl0 5M (-0.17 Ci 90Sr/L in Hanford HLW). Strontium concentrations in Hanford HLW, as shown in Table HI, are about 0.004 Ci "Sr/L and probably not solubility limited. 

Sorption Prediction Equations. Equations predicting radioelement distribution coefficients, K s, as arithmetic functions of component concentrations were obtained for sorption of strontium, neptunium, plutonium, and americium on two Hanford sediments. These equations, presented in Table VH and derived from statistical fits of Box-Behnken experimental designs, were generated for strontium in terms of sodium ion, HEDTA, and EDTA concentrations. Prediction equations for neptunium and plutonium sorption were derived from NaOH, NaA102, HEDTA, and EDTA concentrations. Americium sorption prediction equations were based on NaOH, HEDTA, and EDTA concentrations. 

As shown in Table VII, the equations modeled the data better for neptunium and plutonium than for strontium and americium. The lack of fit for strontium and americium reflected the strong effect that the increased HEDTA and EDTA concentrations had on decreasing the K. The ranges of Kd s observed for strontium and americium were broader, and more difficult to model, than the ranges observed for neptunium and plutonium. 

Predicted rates of the radioelement transport through sediment were found to depend strongly on HLW compositions. Compositions of HLW that are high in HEDTA/EDTA concentrations resulted in 30 to 40 times faster migration rates for americium and strontium. Neptunium and plutonium migration rates increased by factors of 6 to 40 by changing HLW from dilute/noncomplexed to concentrated/complexed compositions. 

July 27, 1982) contained 3830 ppm EDTA. The dramatic increase in EDTA concentration may be due to the installation of the plastic cover over the waste trenches. The presence of this barrier should decrease infiltration by rainwater into the waste trenches resulting in less water accumulation in the "bathtub-like" trenches, thereby possibly resulting in a concentration of any chemical species dissolved in the contaminated groundwater. Water from waste trench 19S, near the center of the burial site, contained 1340 ppb EDTA. Of the many water samples analyzed from the experimental wells and sumps, only groundwater from inert atmosphere well W2NA contained EDTA (1088 ppm, 1009 ppm and 793 ppm on three different sampling dates, see Table IV). 

An indirect AAS method was described for EDTA in the antibiotic streptomycin [42]. The method involved formation of the Ni(II) complex with EDTA, release of complexed Ni(II) by pH adjustment, and subsequent determination of Ni(II) by AAS. EDTA was also determined through its masking effect on the extraction of copper oxinate into methylisobutyl ketone at pH 6.5. The decrease in AAS signal of Cu(II) was linearly proportional to the EDTA concentration [43]. 

Figure 8.9 Interpolated distribution of quasi-total elemental concentrations of Pb (A), Zn (B) and Cu (C) in the soils of the main cities of the Campania region ofltaly (Albanese, 2008), based on aqua regia concentrations, compared with the bioavailable (ammonium acetate-EDTA) concentrations (dots). The data were reclassified by means of the intervention levels established by Italian law D.M. 152/99 (Ministero dell Ambiente, 2006).

Extraction of Am(III) on a POX.11 column this is the main step of the treatment. Before introduction into the POX.11 column, the solution is adjusted to 0.1 to 0.15 M H+ and 0.16 M EDTA. This EDTA concentration corresponds to that of the Fe(III) present. This adjustment is the critical step of the process, as a deficiency of EDTA in relation to Fe(III) results in co-extraction of Fe and Am in the column, thereby reducing capacity of the solvent for americium. Excess EDTA results in the presence of insoluble... 

As described by Sedwick et al. (this issue), a semicontinuous culture of the Ross Sea P. antarctica strain was successively diluted with low-iron (<0.2 nM dissolved Fe) filtered Ross Sea seawater, over a period of several weeks, using a rigorous trace-metal-clean protocol. Using this process, we obtained an inoculum culture of colonial P. antarctica in LI medium diluted 9,140-fold with filtered, low-iron (0.17 nM dissolved Fe) Ross Sea seawater, for which we calculate dissolved Fe and EDTA concentrations of 1.42 nM and 1.25 nM, respectively. Prior to commencing... 

O. 2-pm CritiCap Supor capsule filter (Pall Corporation) into the 1-1 polycarbonate bottle under class-100 filtered air. Subsamples of this 0.2-pm filtered station B seawater were collected for subsequent iron measurements, which confirmed that dissolved Fe concentrations were relatively low (0.17 0.1 nM, n = 4). Based on the concentrations of FeCl3 (11.65 pM) and EDTA (11.71 pM) in the LI medium, the resultant 1-1 inoculum of colonial P. antarctica had initial dissolved Fe and EDTA concentrations of approximately 1.42 and 1.25 nM, respectively. 

The ion-exchange equilibrium of calcium ions is determined by the ratio of the calcium ion species in the solution. Only positive calcium ions (calcium aqua complexes) can participate in the ion-exchange reaction the negative CaEDTA2- and CaHEDTA complexes do not. The ratio of CaEDTA2 and CaHEDTA- depends on the EDTA concentration and pH. When the concentration of EDTA is much smaller than the concentration of calcium ions, the quantity of EDTA complexes is negligible at any pH values. EDTA has an effect when its concentration is more... 

From Table 9 it is observed that, under the conditions of constant temperature and constant linear flow rate, HETP is essentially unchanged over a wide EDTA concentration range. This illustrates that advantage gained from increasing the concentration level of EDTA is not canceled by loss of separation efficiency. It is also apparent from Table 9 that this insensitivity of HETP to EDTA concentration is lost when the concentration of EDTA exceeds 0.075 mol/L and reaches 0.100 mol/L. The concentration of EDTA obviously needs to be confined to a predefined range to assure reproducibility in the separation process. 

Table II. Effect of EDTA Concentration on Calibration Curve Slope °...

The spreadsheet is shown in Figure 17-5. The initial volume of Ca- is entered into cell B3, and the initial Ca- concentration is entered into E2. The EDTA concentration is entered into cell E3. The volumes for which pCa values are to be calculated are entered into cells A5 through AI9. 

Mn zones showed the spread of the radioactivity from the cationic to the anionic values without any electrophoretic zone defined. In other words, at the intermediate EDTA concentrations, which were not high enough to complex all manganese present, both Mn-EDTA complexes and free Mn were present at each position of the electrophoretic rip moving in opposite directions and resulting in the spread of... 

When the EDTA concentration exceeded the stoichiometric amount of copper Initially on the resin, a total release of 80 percent of the Initially bound copper was observed. This result Is not unexpected because of the high formation constant for copper -EDTA complexes. In addition some of the copper In solution was probably due once again to the surface water. 

Remove reagents by passage through Sephacryl S-400 column (50x0.8 cm ) using 10 mM Tris-HCI (pH 7.5) containing 0.1 M NaCl. EDTA concentrations should be kept low ( < 12-fold over Eu) to prevent Eu-dissociation. 

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