Concentrations Of Ethylenediaminetetraacetic Acid Research Articles

Impact of Various Irrigating Agents on Root Fracture: An in vitro Study.

Irrigating solutions are used for cleaning and removing dentinal debris, and the other remains from pulpal space during biomechanical preparation. Therefore, we evaluated the impact of various irrigating agents on root fracture at 5-minute time exposure. We sectioned 60 permanent maxillary premolars with fully formed root structures transversely maintaining the root length of approximately 14 mm. Five study groups were made comprising ethylenediaminetetraacetic acid (EDTA), cetrimide, citric acid, and so on as various irrigating agents. A universal force test machine was used to calculate the force which was enough to fracture each root. Analysis of variance (ANOVA) test was used to access the level of significance. About 10% citric acid solution as an irrigating agent showed minimal fracture opposing results, whereas 10% EDTA solution showed the maximum fracture resistance of root portion. Selection of suitable EDTA concentration that has minimal adverse effect on the mechanical properties of the tooth is very important for the successful management of tooth fracture. About 10% EDTA provided the highest fracture resistance, necessitating the use of irrigating solution in root canal therapy (RCT). Further research with higher and different study groups is required to search for more efficient irrigating solution to improve the outcome of RCT.

Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process**Project supported by the National Natural Science Foundation of China (Grant Nos. 61274074, 61271070, and 61574100).

Ultrathin VO2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO2 nanobelts at 350 °C in air results in the formation of V2O5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V2O5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V2O5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C.

In Vitro Evaluation of Bacteriocins Activity Against Listeria monocytogenes Biofilm Formation.

The present study aimed to assess the activity of cell-free supernatant (CFS) containing bacteriocins on the formation and maintenance of biofilms developed by Listeria monocytogenes, and the associated effect of bacteriocins and ethylene-diamine-tetra-acetic acid (EDTA) on the formed biofilm. CFS from 9 lactic acid bacteria (LAB) strains was tested for inhibitory activity against 85 L. monocytogenes isolates and 21 LAB strains. Then, 12 L. monocytogenes strains were selected based on genetic profiles and sensitivity to CFS and were subjected to an in vitro assay to assess biofilm formation in microtiter plates, considering different culture media and incubation conditions. Based on these results, 6 L. monocytogenes strains were subjected to the same in vitro procedure to assess biofilm formation, being co-inoculated with CFS. In addition, these strains were subjected to the same in vitro procedure, modified by adding the CFS after biofilm formation. Relevant decrease in biofilm formation was observed in the first experiment, but CFS added after biofilm formation did not eliminate them. CFS from Lactobacillus curvatus ET31 were selected due to its anti-biofilm activity, being associated to EDTA at different concentrations and tested for biofilm control of three strains of L. monocytogenes, using the same in vitro procedure described previously. Concentrated bacteriocin presented poor performance in eliminating formed biofilms, and EDTA concentration presented no evident interference on biofilm elimination. Twelve selected L. monocytogenes strains were positive for investigated virulence makers and negative for luxS gene, recognized as being involved in biofilm formation. Selected L. monocytogenes strains were able to produce biofilms under different conditions. CFSs have the potential to prevent biofilm formation, but they were not able to destroy already formed biofilms. Nevertheless, low concentrations of CFS combined with EDTA caused a relevant reduction in already formed biofilms, but this association was not able to eliminate them. The activity of selected CFS was demonstrated against L. monocytogenes-formed biofilms, being more effective when associated to EDTA at different concentrations.

Effect of EDTA-assisted copper uptake on photosynthetic activity and biomass production of sweet Sorghum

Sweet sorghum (Sorghum bicolor L. Moench cv. Rona) is a widely grown sugar crop that is used for bioenergy production. Since sorghum shows increased sensitivity to nutrient deficiency, the objective of this study was to reach an appropriate Cu level in plant tissues using various concentrations of Cu and ethylenediaminetetraacetic acid (EDTA) in order to enhance the photosynthetic activity and biomass production of plants. Copper accumulation increased in the root and stem of plants irrigated for 12 weeks with 0.1 μM CuCl2 both in the presence and absence of 300 μM EDTA and as a consequence, the plant-available Cu concentration in the soil extracts was lower at harvest. Although the copper content of leaves slightly increased, the transport of Fe and Mn, the microelements participating in light reactions of photosynthesis was negatively affected. In spite of this, 0.1 μM CuCl2 alone and with 200 or 300 μM EDTA enhanced the maximal CO2 assimilation rate (Amax) as a function of photon flux density (PPFD) and increased soluble sugar content in all plant parts. The dry mass of plants especially that of stems increased very significantly after 0.1 μM CuCl2 + 300 μM EDTA treatment. These results show that non-toxic concentration of copper in combination with suitable concentration of EDTA can enhance photosynthesis, biomass production, sugar content and the total copper accumulation in the shoot of sweet sorghum plants.

Roles of EDTA washing and Ca2+ regulation on the restoration of anammox granules inhibited by copper(II)

We investigated the feasibility of using ethylene diamine tetraacetic acid (EDTA) washing followed by Ca2+ enhancement for the recovery of anammox reactors inhibited by Cu(II). Kinetic experiments and batch activity assays were employed to determine the optimal concentration of EDTA and washing time; and the performance and physiological dynamics were tracked by continuous-flow monitoring to evaluate the long-term effects. The two-step desorption process revealed that the Cu in anammox granules was primarily introduced via adsorption (approximately, 80.5%), and the portion of Cu in the dispersible layer was predominant (accounting for 71.1%). Afterwards, the Cu internalized in the cells (approximately, 14.7%) could diffuse out of the cells and be gradually washed out of the reactor over the next 20 days. The Ca2+ addition that followed led to an accelerated nitrogen removal rate recovery slope (0.1491kgNm−3d−2) and a normal biomass growth rate (0.054d−1). The nitrogen removal rate returned to normal levels within 90 days and gradual improvements in granular characteristics were also achieved. Therefore, this study provides a new insight that externally removing the adsorbed heavy metals followed by internally repairing the metabolic system may represent an optimal restoration strategy for anammox consortium damaged by heavy metals.

Citric acid and ethylene diamine tetra-acetic acid as effective washing agents to treat sewage sludge for agricultural reuse

This paper presents the effects of different concentrations of citric acid (CA) and ethylene diamine tetra-acetic acid (EDTA) when used as additive reagents for the treatment of sewage sludge for agricultural use. Herein, both the retention of nutrients and removal of metals from the sewage sludge are examined. The average removal rate for the metals after treatment by CA decreased in the order Cu>Pb>Cd>Cr>Zn, while the rates after treatment by EDTA decreased in the order of Pb>Cu>Cr>Cd>Zn. After treatment with CA and EDTA, total nitrogen and total phosphorus concentrations in the sludge decreased, while the content of available nitrogen and Olsen-P increased. In addition, a multi-criteria analysis model-fuzzy analytic network process method (with 3 main factors and 12 assessment sub-factors) was adopted to evaluate the effectiveness of different treatment methods. The results showed that the optimal CA and EDTA concentrations for sewage sludge treatment were 0.60 and 0.125mol/L, respectively.

Competitive Effects of Calcium and Magnesium Ions on the Photochemical Transformation and Associated Cellular Uptake of Iron by the Freshwater Cyanobacterial Phytoplankton Microcystis aeruginosa.

Photochemical reduction of iron and iron uptake by Microcystis were investigated in a freshwater medium (pH 8) containing a range of calcium (Ca) and magnesium (Mg) ion concentrations (0.002-20 mM). In a medium containing the chelator ethylenediaminetetraacetic acid (EDTA), 50-fold increases in net photochemical formation rates of unchelated ferrous iron (Fe(II)') were observed as the concentration of calcium or magnesium metal (Me) was increased to exceed the concentration of EDTA. Kinetic modeling of iron transformation processes indicated that the facilitated Fe(II)' formation is attributed to Me-promoted photoreductive dissociation of the ferric iron-EDTA complex. In the medium containing Suwanee River fulvic acid, in contrast, the competitive effect of Me on photochemical Fe(II)' formation appears to be negligible due to the weak binding affinities of fulvic acid to Me. The cellular iron uptake rate in the EDTA-buffered system increased by ∼3-fold in the excess Me condition where the increased rate of photochemical Fe(II)' formation was observed, whereas the presence of Me resulted in a decrease in iron uptake rate in the fulvic acid system (by up to 5-fold). The decrease in iron uptake is likely caused by Me binding to iron transporters and other entities involved in intracellular iron transport. The findings of this study indicate a significant effect of Ca and Mg concentrations in natural waters on iron uptake by Microcystis, with the magnitude of effect depending strongly on ligand type.

The Use of EDTA As a Mechanistic Probe of Magnesium Corrosion in Chloride Containing Electrolyte

Despite recent developments which have led to a better understanding of the localized corrosion behavior of magnesium (Mg) in chloride electrolyte, there are certain characteristics which remain unclear. One such aspect is the enhanced electro-catalytic activity of the dark corroded Mg surface to cathodic hydrogen evolution, previously demonstrated in several recent publications. It has also been shown that in many instances, the time-dependent Mg corrosion rate increases in proportion to the area of cathodically- activated dark surface produced in the early stages of localized corrosion propagation. It has been proposed that the effect is due to enrichment in transition metal impurity phases on the anodically attacked Mg surface. However, direct evidence of such enrichment has proved difficult, although recent reports have located iron-rich particles within the corrosion product layer (1) and interfacial Fe enrichment on a corroded Mg by Rutherford backscattering spectroscopy (2). In this work the localized corrosion of commercial purity Mg, comprising a 280 ppm Fe impurity level, is investigated in the presence and absence of ethylene diamine tetra-acetic acid (EDTA), at different concentrations and pH values, when immersed in aqueous sodium chloride electrolyte. The aim of the investigation is to exploit the ability of EDTA to act as a chelating agent for Mg2+ and transition metal ions such as Fe2+, so that the principal influencing factors causing the propagation of cathodically activated dark regions on corroding Mg may be identified. The presence of EDTA in 1 mol dm-3 NaCl (aq) at pH 6 is shown to markedly decrease the rate of Mg corrosion in freely corroding conditions, as shown by the plots of time dependent hydrogen evolution (HE) given in Figure 1. Increasing the concentration of EDTA progressively reduces the rate of HE and produces a change in kinetics, where a monotonic increase in the quantity of hydrogen evolved with time is observed. This is in contrast to the exponential relationship seen over the first 60 min immersion for the control experiment and at a lower EDTA concentration. The decrease in corrosion rate is accompanied by a significant change in the visual appearance of the corroding surface. Although dark, expanding circular corrosion features propagate in the presence of 10-3 mol dm-3EDTA, no such behavior is observed when the concentration is increased by an order of magnitude, and the exposed surface remains covered by a cloudy white film. In-situ SVET shows no evidence of localized corrosion patterns characteristic of the un-inhibited case even over protracted immersion times of several hours. Similar observations are observed at higher pH although the influence of EDTA on bulk rates of HE are not as marked when compared to the control case. In separate experiments, where localized corrosion is allowed to propagate before EDTA addition to the corrosive electrolyte, significant changes in current density patterns are observed at the point of addition. This is shown in Figure 2, where EDTA halts propagation and the intense local anodic activity observed at the perimeter of the corroded area becomes displaced to the remaining intact (uncorroded) surface, although at significantly lower current density values. The observations of a strongly mitigated HE rate seem to be inconsistent with a scenario where EDTA complexation of Mg2+ ions prevents deposition of surface corrosion product. A theory is proposed to explain the action of EDTA in terms of its ability to strongly chelate Fe2+, possibly present in the direct vicinity of the corroding Mg surface, in a situation where Fe-rich impurity phases become detached from the matrix and corrode independently of the matrix. The possibility of subsequent re-plating of Fe onto the corroding Mg to produce an electro-catalytically activated surface is considered. The acceleration of HE rates from corroding Mg surfaces on which iron re-plating has taken place is confirmed by experimentation.

Cadmium Remediation by Arbuscular Mycorrhizal Fungus–Colonized Celery Plants Supplemented with Ethylenediaminetetraacetic Acid

ABSTRACTA pot trial using Glomus mosseae along with EDTA (ethylenediaminetetraacetic acid) was conducted for the phytoextraction of cadmium (Cd) by celery (Apium graveolens Linn.) plants from soil artificially contaminated with Cd under glass house conditions. The experiment is a 2 × 2 × 4 factorial design with two levels of G. mosseae inoculations (G. mosseae inoculated and uninoculated), two EDTA concentrations (without and with 2.5 mmol kg−1 soil EDTA) and four Cd concentrations (0, 5, 10, and 20 mg kg−1 soil). The results indicate the formation of an effective symbiosis between G. mosseae and celery in the contaminated soil. However, an increase in Cd input level and EDTA addition showed strong phytotoxic effect on celery plants and G. mosseae, as a considerable decrease in the frequency of root colonization and spore density was noticed. However, the plants were able to withstand the stressed condition due to the benefits provided by G. mosseae through increased P accumulation, chlorophyll content, and plant growth, resulting in an increase in Cd accumulation, which was good enough for the phytoextraction purpose. Thus, celery plants inoculated with G. mosseae and later supplemented with EDTA could be an effective and potentially suitable practice for the remediation of Cd-contaminated sites.

Effect of EDTA and NH4Cl additives on electrodeposition of Zn–Ni films from choline chloride-based ionic liquid

Two additives of ethylene diamine tetraacetic acid (EDTA) and ammonium chloride (NH4Cl) were separately used in the electrodeposition of Zn–Ni alloy films from a deep eutectic solvent. The effects of these two additives on electrodeposition behavior, composition, morphology, and corrosion performance of the Zn–Ni alloys were investigated. The electrodeposition behaviors of Zn–Ni alloy revealed by the cyclic voltammetry show that the addition of EDTA to the Zn–Ni electrolyte enhances the Zn incorporation into the alloy film while the addition of NH4Cl produces an opposite effect by suppressing Zn incorporation into the film. With an increase of EDTA concentration in the electrolyte, the Zn content of the Zn–Ni films increases, while the grain size of the deposits and the current efficiency of the plating process decrease. The increase of NH4Cl concentration in the electrolyte would significantly refine the grain size of the electrodeposited Zn–Ni films, reduce the Zn content and increase the cathodic current efficiency. The corrosion testing indicates that the barrier corrosion resistances of Zn–Ni films electrodeposited from NH4Cl containing electrolytes are superior to those electrodeposited from EDTA-containing electrolytes, which in turn are superior to those electrodeposited from additive-free electrolytes.

A novel strategy for accelerating the recovery of an anammox reactor inhibited by copper(II): EDTA washing combined with biostimulation via low-intensity ultrasound

Excessive heavy metals are inhibitory or even toxic to microorganisms in biological wastewater treatment systems. Given the promising prospects of anaerobic ammonium oxidation (anammox), this work details a novel remediation strategy for preventing anammox failure due to heavy metal overload (in this study, Cu(II) overload). The strategy involves combining ethylenediamine tetraacetic acid (EDTA) washing with bioactivity stimulation via low-intensity ultrasound. Kinetic experiments and batch activity assays were employed to determine the optimal concentration of EDTA and washing time, and changes in reactor performance and granule characteristics were tracked by continuous-flow monitoring to evaluate the long-term effects. The two-step desorption process revealed that the Cu in anammox granules was primarily introduced via adsorption (approximately 84.9%) and that low-energy adsorption sites were predominant (accounting for 58.6%). The Cu internalized in the cells (approximately 12.5%) could then diffuse out of the cells and be gradually washed out of the reactor within 20days. Thereafter, ultrasound irradiation at intervals of 8days contributed to accelerated performance, with a nitrogen removal rate (NRR) increasing rate of 0.1971kgNm−3d−2. The NRR was able to return to normal levels within 64days, whereas the recovery of dehydrogenase activity (DHA) was hysteretic, requiring approximately 110days. Gradual improvements in granule diameter, settling properties, extracellular polymeric substances and heme content were also detected. Overall, these results demonstrate that external removal of the adsorbed Cu followed by internal repair of the metabolic system may represent an important and useful recovery method in wastewater treatment plant operation.

Evaluation of test strips for the rapid identification of ethylenediaminetetraacetic acid (EDTA) specimens.

Identification of specimens that contain ethylenediaminetetraacetic acid (EDTA) is frequently necessary when investigating potentially mislabeled or improperly collected specimens. To evaluate the performance of rapid EDTA detection test strips in clinical specimens. We applied specimens to test strips designed to detect EDTA (QUANTOFIX EDTA) using a pipet (drop mode). Reactions were scored visually on a scale from red (no EDTA) to orange (low/indeterminate EDTA) to yellow (contains EDTA). Test strips reliably identified specimens from EDTA-containing tube types. Although test strips did not detect strong reactivity in other specimens, tubes containing NaFl/K-oxalate produced an orange (low/indeterminate EDTA) reaction. Bismuth and citrate levels were higher in specimens after we dipped test strips into solution (dip mode). Test strips detected the presence of EDTA in concentrations found in EDTA-containing primary tubes. Test strips were less effective in evaluating low-level EDTA concentrations expected with intravenous line contamination or backflow. Indeterminate reactions required further investigation. Dip mode can produce analytical problems for assays that measure (or are interfered by) the contents of test strips.

Relevance of EDTA carryover during blood collection.

The order of draw is regarded as a preanalytical issue to prevent carryover of additives during blood collection. Our objective was to prove the theory of ethylenediaminetetraacetic acid (EDTA) carryover for a closed vacuum system and the influence of EDTA on concentrations of selected biomarkers. To test the carryover of EDTA, a blood collection with tripotassium EDTA (K3EDTA) and subsequent non-additive tubes was simulated using distilled water as substitute for blood. EDTA concentrations were measured by tandem mass spectrometry. Then we added increasing concentrations of EDTA to heparinized blood and measured routine biomarkers, thereby simulating a carryover of EDTA whole blood and pure EDTA, respectively. Additionally, we tested for EDTA contamination and biomarker alteration in samples collected from 10 healthy volunteers by a syringe with subsequent transfer into sample tubes. No EDTA contamination was detected in samples collected subsequent to a K3EDTA tube when adhering to guidelines of blood sampling. Magnesium, calcium, and potassium levels were altered by artificial K3EDTA whole-blood contamination as well as when adding 1 μL pure K3EDTA. Iron values were altered at EDTA concentrations of 4.4 mmol/L. All other parameters remained unaffected. A slight EDTA carryover was observed in syringe collection and subsequent transfer into EDTA and heparin tubes, however, without any biomarker alteration. An EDTA carryover during blood collection using a closed vacuum system is highly unlikely. Even if carryover of EDTA whole blood occurs, an absolute volume larger than 10 μL would be necessary to alter test results. However, contamination of samples with preloaded pure K3EDTA solution by severe neglect of current recommendations in blood collection may significantly alter testing results.

A Study of How Chelating Agents Interact with Neutral Lipid Membranes

Chelating agents are used in a range of areas, from treating metal poisoning in medicine to removing unwanted heavy metal ions from a given solution in biochemistry. Specifically, ethylenediaminetetraacetic acid (EDTA) is widely used in biochemistry and other areas of science to sequester polyvalent cations such as Ca2+ and Fe3+ from solutions. Small angle x-ray scattering [1] has shown that low concentrations (mM range) of EDTA in solution introduce a phase coexistence in homogeneous 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) multilamellar vesicles. This suggests that there are interactions taking place between EDTA and the lipid head group. We investigate the interaction of EDTA with lipids in the presence of various cations, using 1H NMR. A discussion of the interactions present between EDTA and lipids will be formulated based on observed proton chemical shifts and relaxation rates.[1] Johnson et al, Langmuir 2014.

Highly Sensitive Determination of Ethylenediaminetetraacetic Acid Using a Permanganate Chemiluminescence System Catalyzed by Gold Nanoparticles.

A sensitive and selective chemiluminescence method was developed to determine ethylenediaminetetraacetic acid (EDTA) in water samples. It was observed that gold nanoparticles (AuNPs) catalyzed chemiluminescence (CL) reactions of permanganate-aldehydes which underwent an enhancement effect in the presence of iron(III) ions (Fe(3+)). This effect is more remarkable in the presence of EDTA, and a highly intensive CL emission is created in proportion to the EDTA concentration. These observations form the basis of the method for the high sensitive determination of EDTA in the 0.83 - 167 nmol L(-1) concentration range, with a detection limit of 0.25 nmol L(-1). The relative standard deviations for five repeated measurements of 5, 40 and 140 nmol L(-1) EDTA were 1.14, 2.48 and 0.65%, respectively. The method has good selectivity toward EDTA, and there are no interferences from other ions. The offered method has good precision, and was satisfactorily used for the sensitive determination of EDTA in water samples.

Ex situ remediation technology for heavy metals in contaminated sediment

The importance of metal mobile fractions rather than total contents in environmental matrices is increasing in the risk assessment evaluation of contaminated sites. Ethylenediaminetetraacetic acid (EDTA), aimed at the measurements of metals mobile fractions, was used to extract the metals from the contaminated dredged sediments based on chemical extraction technology. This work examined the influences of contact time and EDTA concentration on the extraction efficiency for metals from polluted dredged sediment. In addition, the sequential extraction method was carried out to show the change in distribution pattern of metals in sediment before and after EDTA extraction. The dredged sediment from Helwan area (H) was mainly polluted by Pb (685 mg/kg), and the dredged sediment from Talkha area (T) was significantly polluted by Cd (236 mg/kg), Cu (229 mg/kg), and Zn (2,888 mg/kg). For sediment (H), the maximum lead removal of 72.54% was achieved using EDTA under the optimum conditions. While For sediment (T), the maximum cadmium removal of 53.58% was achieved under the same conditions. Finally, EDTA can be used as washing solution for contaminated sediment as well as single-step extraction to identify non-residual metal content (the anthropogenic fraction) and to evaluate the potential bioavailability of metal.

Purification and characterization of a digestive lipase in the midgut of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)

Ectomyelois ceratoniae is one of the key constraints in the production of pomegranate and pistachio in Iran. Since there is little knowledge on digestive lipases of insects, the current study aimed to purify and characterize the enzyme in the midgut of E. ceratoniae. Purification by ammonium sulfate, Sephacryl G-100 and Di-ethyl-amino-ethanol (DEAE)–cellulose fast flow revealed an enzyme with a specific activity of 0.4 U mg–1 protein, 29.62 of recovery, 28.57 of purification fold and 25 kDa of molecular weight. The purified lipase showed the highest activities at pH 7 and a temperature of 30°C. The enzyme was stable for 3 h at 30°C. Different concentrations of phenylmethylsulfonyl fluoride (PMSF) and ethylenediaminetetraacetic acid (EDTA) were used to find possible inhibition of the purified lipase. It was observed that different concentrations of EDTA had no inhibitory effects but different concentrations of PMSF significantly decreased activity of the purified lipase. Since long chain unsaturated fatty acids are essential dietary components, inhibition of digestive lipases may cause severe reduction in growth and development of insects. Hence, study of the biochemical properties of insect digestive lipases is necessary to consider their inhibitions in plant breeding programs as a component of integrated pest management.

H2O2 and/or photocatalysis under UV-C irradiation for the removal of EDTA, a chelating agent present in nuclear waste waters

In this study, we compare the efficiency of photocatalytic processes based on TiO2 (Degussa P-25) and UV/H2O2 as a means of degrading and mineralizing ethylenediaminetetraacetic acid (EDTA) under UV-C irradiation. EDTA was the molecule studied here because it is present in high proportions at nuclear facilities, where it is used for cleaning and decontamination purposes because of its chelating properties. The photonic power of the UV-C lamps used (13 and 15W) was established using actinometric and Keitz's methods. The adsorption of EDTA on TiO2 Degussa P-25 corresponds to a Langmuir isotherm, and the photocatalytic degradation process is consistent with the Langmuir–Hinshelwood model. During the photocatalytic process, an increase in the initial EDTA concentration favors the formation of large quantities of intermediates, which occupy the active sites, thus delaying the production of detectable quantities of oxalic acid. The results obtained here also show that nitrogen originating from EDTA molecules is mainly converted into ammonium and nitrate ions with a conversion rate of 67%. In addition, the amount of oxalic acid formed increases with the pH. The efficiency of the UV/TiO2 and UV/H2O2 processes as a means of EDTA degradation was found to be similar, provided H2O2 was added continuously during the UV/H2O2 process. The quantum efficiency was calculated and found to be equal to 0.9% in the case of photocatalysis and 1.4% in that of UV/H2O2.

Composition control of co-electroplating Au–Sn deposits using experimental strategies

The optimal electroplating parameters for a pulse-current co-electroplating system of Au–Sn deposits in a non-cyanide electrolyte were investigated using experimental strategies, including fractional factorial design (FFD) and central composite design (CCD) coupled with the response surface methodology. pH value, ethylene diamine tetraacetic acid (EDTA) concentration, catechol concentration and metallic ions molar ratio (i.e., [Au]/[Sn]) were identified as the key factors affecting the composition of Au–Sn deposits in the FFD study. A reliable model between the response variable and the key factors of pH value, EDTA concentration and catechol concentration was established for the composition control of Au–Sn alloys in the CCD study. The standard deviation of the response variable (tin content) was set at the minimum level to determine the optimal co-electroplating parameters for the predicted composition value of Au–Sn deposits. Pair T test was conducted to validate both predicted and observed composition values under the optimal electroplating parameters, and the composition of Au–Sn deposits can be precisely controlled based on the established model. Scanning electron microscope observation and X-ray diffractometer analysis revealed that the morphology and crystalline of the Au–Sn deposits were composition-dependent.

Determination of Ethylenediaminetetraacetic Acid from Swine Organs, Feces, Urine, and Plasma by Liquid Chromatography Tandem Mass Spectrometry

The study describes the development of a method for determination of ethylenediaminetetraacetic acid (EDTA) in various biological matrices after extraction as sample preparation using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The method is based on the complex formation of the excess of EDTA with FeIII. The excretion of EDTA in swine, treated with high doses of EDTA against dysentery, was monitored over a week by measuring its concentration in urine, plasma, and feces after stopping the administration of the medication. After slaughter, the EDTA concentration was measured also in the fatty tissue, kidney, liver, and muscle in order to determine the distribution of its residue between the tissues. The new method is fast, and the one-step sample preparation procedure may be regarded as derivatization. The method is applicable for low-concentration analysis with 3.0 ng mL−1 limit of detection and 10.0 ng mL−1 limit of quantification, while the relative standard deviation does not exceed 4.3 %.