Showing papers on "Oxalic acid published in 2001"
TL;DR: The hygroscopic properties of selected water-soluble dicarboxylic acids and multifunctional acids were studied using single droplets levitated in an electrodynamic balance and the modified UNIFAC model improves the agreement of predictions and measurements to within 38% for all the acids studied.
Abstract: The role of water-soluble organic compounds on the hygroscopic properties of atmospheric aerosols has recently been the subject of many studies. In particular, low molecular weight dicarboxylic acids and some multifunctional organic acids have been found or are expected to exist in atmospheric aerosols in urban, semiurban, rural, and remote sites. Unlike for their inorganic counterparts, the hygroscopic properties of organic acids have not been well characterized. In this study, the hygroscopic properties of selected water-soluble dicarboxylic acids (oxalic acid, malonic acid, succinic acid, and glutaric acid) and multifunctional acids (citric acid, DL-malic acid, and L-(+)-tartaric acid) were studied using single droplets levitated in an electrodynamic balance at 25 degrees C. The water activities of bulk samples of dilute solutions were also measured. Solute evaporation was observed in the dicarboxylic acids but not in the multifunctional acids. Oxalic acid, succinic acid, and glutaric acid droplets crystallize upon evaporation of water, but, except for glutaric acid droplets, do not deliquesce even at 90% relative humidity (RH). Mass transfer limitation of the deliquescence process was observed in glutaric acid. Neither crystallization nor deliquescence was observed in malonic acid, citric acid, DL-malic acid, or L-(+)-tartaric acid. Malonic acid and these three hydroxy-carboxylic acids absorb water even at RH much lower than their respective deliquescence RH. The growth factor (Gf), defined as the ratio of the particle diameter at RH = 10% to that at RH = 90%, of oxalic acid and succinic acid was close to unity, indicating no hygroscopicity in this range. The remaining acids (malonic acid, glutaric acid, citric acid, malic acid, and tartaric acid) showed roughly similar hygroscopicity of a Gf of 1.30-1.53, which is similar to that of "more hygroscopic" aerosols in field measurements reported in the literature. A generalized equation for these four acids, Gf = (1-aw)-0.163, was developed to represent the hygroscopicity of these acids. Water activity predictions from calculations using the UNIFAC model were found to agree with the measured water activity data to within 40% for most of the acids but the deviations were as large as about 100% for malic acid and tartaric acid. We modified the functional group interaction parameters of the COOH(-H20, OH-H20, and OH-COOH pairs by fitting the UNIFAC model with the measured data. The modified UNIFAC model improves the agreement of predictions and measurements to within 38% for all the acids studied.
466 citations
TL;DR: In this paper, the behavior of synthetic B-doped diamond thin-film electrode (BDD) was studied in acid media contg. 4-chlorophenol (4-CP) by cyclic voltammetry, chronoamperometry, and bulk electrolysis.
Abstract: The electrochem. behavior of synthetic B-doped diamond thin-film electrode (BDD) was studied in acid media contg. 4-chlorophenol (4-CP) by cyclic voltammetry, chronoamperometry, and bulk electrolysis. The results showed that in the potential region of supporting electrolyte stability occur reactions involving the oxidn. of 4-CP to phenoxy radical and 1,4-benzoquinone. Polymeric materials, which result in electrode fouling, are also formed in this potential region. Electrolysis at high anodic potentials, in the region of electrolyte decompn., complex oxidn. reactions can take place involving electro-generated hydroxyl radicals, leading to the complete incineration of 4-chlorophenol. Electrode fouling is inhibited under these conditions. The exptl. results were compared with a theor. model. This model is based on the assumption that the rate of the anodic oxidn. of 4-CP is a fast reaction. HPLC analyses revealed that the main intermediate products of 4-CP oxidn. were 1,4-benzoquinone, maleic acid, formic acid, and oxalic acid. [on SciFinder (R)]
382 citations
TL;DR: A comprehensive study to evaluate the relative antibrowning activity of 36 known compounds was conducted in this article, where five chemical groups, including carboxylic acids, ascorbic acid derivatives, sulfur containing amino acids, phenolic acids and other miscellaneous compounds were tested on apple slices under the same conditions.
265 citations
TL;DR: An adhesion/decalcification concept was advanced that predicts that carboxylic acids, regardless of concentration/pH, either adhere to or decalcify hydroxyapatite, depending on the dissolution rate of the respective calcium salts in the acid solution.
Abstract: Fundamental to the processes of decalcification of or adhesion to mineralized tissues is the molecular interaction of acids with hydroxyapatite. This study was undertaken to chemically analyze the interaction of 1 mono-, 2 di-, 1 tri-, and 2 polycarboxylic acids with hydroxyapatite in an attempt to elucidate the underlying mechanism. Maleic, citric, and lactic acid decalcified hydroxyapatite, in contrast to oxalic acid and the two polycarboxylic acids that were chemically bonded to hydroxyapatite. Solubility tests showed that the calcium salts of the former were very soluble, whereas those of the latter could hardly be dissolved in the respective acid solutions. Based on these data, an adhesion/decalcification concept was advanced that predicts that carboxylic acids, regardless of concentration/pH, either adhere to or decalcify hydroxyapatite, depending on the dissolution rate of the respective calcium salts in the acid solution. This contrasting behavior of organic acids most likely results from their differential structural conformations.
245 citations
TL;DR: In this paper, the formation of lipid compounds during anaqueous Fischer-Tropsch-type reaction was studied withsolutions of oxalic acid as the carbon and hydrogensource.
Abstract: The formation of lipid compounds during anaqueous Fischer-Tropsch-type reaction was studied withsolutions of oxalic acid as the carbon and hydrogensource. The reactions were conducted in stainlesssteel vessels by heating the oxalic acid solution atdiscrete temperatures from 100 to 400 °C, atintervals of 50 °C for two days each. Themaximum lipid yield, especially for oxygenatedcompounds, is in the window of 150–250 °C. At atemperature of 100 °C only a trace amount oflipids was detected. At temperatures above150 °C the lipid components ranged from C12to >C33 and included n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanals, n-alkanones, n-alkanes, andn-alkenes, all with essentially no carbon numberpreference. The n-alkanes increased inconcentration over the oxygenated compounds attemperatures of 200 °C and above, with a slightreduction in their carbon number ranges due tocracking. It was also noted that the n-alkanoicacids increased while n-alkanols decreased withincreasing temperature above 200 °C. Attemperatures above 300 °C synthesis competeswith cracking and reforming reactions. At 400 °Csignificant cracking was observed and polynucleararomatic hydrocarbons and their alkylated homologswere detected. The results of this work suggest thatthe formation of lipid compounds by aqueous FTTreactions proceeds by insertion of a CO group at theterminal end of a carboxylic acid functionality toform n-oxoalkanoic acids, followed by reductionto n-alkanoic acids, to n-alkanals, thento n-alkanols. The n-alkenes areintermediate homologs for n-alkan-2-ones andn-alkanes. This proposed mechanism for aqueousFTT synthesis differs from the surface-catalyzedstepwise FT process (i.e., gaseous) of polymerization of methylene reported in the literature.
234 citations
TL;DR: In this paper, the effects of pH, amount of deposited Pt and additives of inorganic anions on the rate of the reaction were also studied, and a possible reaction mechanism was discussed.
Abstract: Photocatalytic hydrogen evolution using oxalic acid as electron donor has been investigated over Pt–TiO2 prepared by photodeposition. The reaction kinetics is consistent with the Langmuir model. The effects of pH, amount of deposited Pt and additives of inorganic anions on the rate of the reaction were also studied. A possible reaction mechanism was discussed.
232 citations
TL;DR: In this paper, the results of low-grade Joda manganese ore containing 24.7% Mn and 28.4% Fe were carried out at high temperature and atmospheric pressure using oxalic acid as reductant in sulphuric acid medium.
188 citations
TL;DR: In this article, a general reaction pathway for the degradation of each pollutant is proposed, where the initial mineralization rate increases as more oxidizing hydroxyl radical is produced in the medium by the catalyzed ozonations.
Abstract: Solutions with 1.07 mmol dm−3 aniline or with 1.38 mmol dm−3 4-chlorophenol at pH ca. 3 have been treated with ozone and ozonation catalyzed with Fe2+ and/or UVA. The initial mineralization rate increases as more oxidizing hydroxyl radical is produced in the medium by the catalyzed ozonations. Direct ozone treatment leads to stable oxidation products, which are quickly destroyed under UVA illumination. In the presence of Fe2+ as catalyst, the degradation process is inhibited by the formation of Fe3+ complexes with short organic diacids, being photodecomposed by UVA light. Each initial pollutant is destroyed at similar rate in all processes. p-Benzoquinone and nitrobenzene are identified as intermediates of aniline oxidation. The former product is only detected when high amounts of hydroxyl radical are produced by the action of Fe2+. Ammonium ion released during p-benzoquinone formation is also generated in larger extension under the same conditions. Nitrate ion reaches maximum production under UVA irradiation, indicating that generation of nitrobenzene from selective attack of O3 on the amino group of aniline is photocatalyzed. Reaction of 4-chlorophenol with ozone leads to 4-chloro-1,3-dihydroxybenzene and 4-chloro-1,2-dihydroxybenzene. The last product is produced in larger extension when high amounts of hydroxyl radical can selectively attack the initial pollutant. Chloride ion is completely lost during the further degradation of both dihydroxylated derivatives. Oxidation of all aromatic intermediates detected during aniline and 4-chlorophenol degradation gives maleic acid, which is further mineralized via oxalic acid. A general reaction pathway for the degradation of each pollutant is proposed.
187 citations
TL;DR: The measured rhamnolipid-metal stability constants were found in most cases to be similar or higher than conditional stability constants reported in the literature for metal complexation with acetic acid, oxalic acid, citric acid, and fulvic acids.
Abstract: The presence of toxic metals in natural environments presents a potential health hazard for humans. Metal contaminants in these environments are usually tightly bound to colloidal particles and organic matter. This represents a major constraint to their removal using currently available in situ remediation technologies. One technique that has shown potential for facilitated metal removal from soil is treatment with an anionic microbial surfactant, rhamnolipid. Successful application of rhamnolipid in metal removal requires knowledge of the rhamnolipid-metal complexation reaction. Therefore, our objective was to evaluate the biosurfactant complexation affinity for the most common natural soil and water cations and for various metal contaminants. The conditional stability constant (log K) for each of these metals was determined using an ion-exchange resin technique. Results show the measured stability constants follow the order (from strongest to weakest): Al3+ > Cu2+ > Pb2+ > Cd2+ > Zn2+ > Fe3+ > Hg2+ > Ca2+ > Co2+ > Ni2+ > Mn2+ > Mg2+ > K+. These data indicate that rhamnolipid will preferentially complex metal contaminants such as lead, cadmium, and mercury in the presence of common soil or water cations. The measured rhamnolipid-metal stability constants were found in most cases to be similar or higher than conditional stability constants reported in the literature for metal complexation with acetic acid, oxalic acid, citric acid, and fulvic acids. These results help delineate the conditions under which rhamnolipid may be successfully applied as a remediation agent in the removal of metal contaminants from soil, as well as surface waters, ground water, and wastestreams.
176 citations
TL;DR: In this paper, the authors analyzed aerosol samples from the South African savanna were analyzed for their polar organic constituents and found that Oxalic acid was the dominating compound with an average amount of 79.2 ǫ m−m−3 on the front filter and 11.3 nǫ n−m −3 on a back-up filter.
170 citations
TL;DR: It is proposed that the wood-rotting basidiomycete acquires biochemical energy by oxidizing glucose to oxalate by the occurrence of the unprecedented metabolic coupling of the TCA and glyoxylate cycles that support oxalic acid biosynthesis.
Abstract: A metabolic mechanism for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris has been proposed on the basis of biochemical analyses of glucose metabolism. There was a strong correlation between glucose consumption and oxalate production. Oxalic acid was found to accumulate in the culture fluid in about 80% of the theoretical yield or about 5-fold, on the basis of the fungal biomass harvested. The results clearly indicate that glucose was not completely oxidized to CO(2) by the tricarboxylic acid (TCA) cycle but converted mainly to oxalate. The determination of the 12 enzymes concerned has revealed the occurrence of the unprecedented metabolic coupling of the TCA and glyoxylate cycles that support oxalate biosynthesis. In this metabolic system, isocitrate lyase (EC ), together with oxaloacetase (EC ), was found to play a pivotal role in yielding oxalate from oxaloacetate via the acetate-recycling routes. Moreover, malate dehydrogenase (EC ), with an extraordinarily high activity among the enzymes tested, was shown to play an important role in generating NADH by oxidation of malate to oxaloacetate. Thus, it is proposed that the wood-rotting basidiomycete acquires biochemical energy by oxidizing glucose to oxalate.
TL;DR: In this paper, the electrochemical polymerization of several ring-substituted anilines, namely of o-toluidine (o-Tol), m-toline (m-Toline), o-anisidine (oAnis), and o-chloroaniline (O-ClAn), was carried out on passivated Fe surfaces.
TL;DR: The results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, theOxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via D-mannose and L-galactose is operational in individual P. Stratiotes Crystal idiobasts.
Abstract: L-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various (14)C-labeled compounds and examined by micro-autoradiography for incorporation of (14)C into calcium oxalate crystals. [(14)C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-(14)C]AsA also gave heavy labeling of crystals, whereas [6-(14)C]AsA gave no labeling. Labeled precursors of AsA (L-[1-(14)C]galactose; D-[1-(14)C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, D-[1-(14)C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > L-galactose > D-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via D-mannose and L-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments.
TL;DR: In this paper, a gas chromatographic method was developed to assess amino acid enantiomer concentrations in complex soil matrices following hot HCl hydrolysis (6 M, 12 h, 1058C).
Abstract: Determination of amino acid enantiomers in environmental samples is difficult, because metals and organic impurities interfere with the analyses. We developed a new gas chromatographic method to assess amino acid enantiomer concentrations in complex soil matrices following hot HCl hydrolysis (6 M, 12 h, 1058C). The crucial focus was the establishment of a simple, reliable sample clean-up procedure. The presented method involved the adsorption of the enantiomers on a Dowex 50 W X8 cation exchange resin and the removal of interfering compounds with 0.1 M oxalic acid prior to amino acid elution with 2.5 M NH4OH. After conversion to N-pentafluoropropionyl-amino acid iso-propyl esters, the diastereomers were separated by a Chirasil l-Val capillary column and quantified by a flame ionization or mass selective detector. The lower limit of quantification tested here was #1 pg injection amount. The recovery of amino acid enantiomers averaged 99 ^ 11% for pure standards and 97 ^ 11% for spiked soil hydrolysates. The general applicability of the method was demonstrated by determination of amino acid enantiomers in taxonomically different soils from different geographic regions. The coefficients of variation presented by d/l ratios were 12% for alanine and ,10% for the other amino acids. q 2001 Elsevier Science Ltd. All rights reserved.
TL;DR: The zinc oxalate coordination polymers Zn(ox)(Py)2 (1) and [methylpyridinium]2[Zn2(ox)3] (2) have been synthesized via unexpected oxidation of ethanol and oxidative coupling of methanol under hydro(solvo)thermal conditions as mentioned in this paper.
Abstract: The zinc oxalate coordination polymers Zn(ox)(Py)2 (1) and [methylpyridinium]2[Zn2(ox)3] (2) have been synthesized via unexpected oxidation of ethanol and oxidative coupling of methanol under hydro(solvo)thermal conditions. 1 adopts a 1D zigzag chain structure in which the Zn centers are linked by exo-tetradentate oxalate groups, while 2 exhibits an interesting layered architecture with 12-membered honeycomblike openings (composed of 6 Zn atoms and 6 oxalates).
TL;DR: In this article, the reduction of nitrate ion (NO3−) in an aqueous suspension of metal-loaded titanium(IV) oxide (TiO2) was examined in the presence of oxalic acid (OA) as a hole scavenger.
Abstract: Photocatalytic reduction of nitrate ion (NO3−) in an aqueous suspension of metal-loaded titanium(IV) oxide (TiO2) was examined in the presence of oxalic acid (OA) as a hole scavenger. Conversion of NO3− into ammonia (NH3) competed with hydrogen liberation, and the NH3 production selectivity increased with the order of loaded metal, (Pt, Pd, Co) < (Ni, Au) < (Ag, Cu), which was attributable to the efficiency of reduction of protons by photogenerated electrons at the loaded metal, i.e., hydrogen overvoltage of the loaded metal. TiO2 powder loaded with Cu showed higher NH3 yield and selectivity as well as higher efficiency of OA consumption. TiO2 with in situ deposited Cu gave results comparable to those of a Cu pre-loaded photocatalyst.
TL;DR: In this paper, it was shown that 2,4-dichlorophenoxyacetic acid undergoes efficient degradation when an O2- or Ar-saturated aqueous solution is subjected to high-frequency (640 kHz) sonolysis.
Abstract: 2,4-dichlorophenoxyacetic acid (2,4-D) undergoes efficient degradation when an O2- or Ar-saturated aqueous solution is subjected to high-frequency (640 kHz) sonolysis. 2,4-dichlorophenol, hydroquinone, and catechol are major reaction intermediates common to various experimental conditions. The similarities between the reaction intermediates of sonolytic and radiolytic reactions indicate •OH radical as the primary reactive species responsible for 2,4-D degradation. Very little 2,4-D degradation occurs if the sonolysis is carried out in the presence of the •OH radical scavenger tert-butyl alcohol, also indicating that little or no pyrolysis of the compound occurs. Most of the 2,4-D eventually forms oxalic acid, which, unlike other •OH-mediated oxidation methods, is not easily mineralized with high-frequency ultrasound.
TL;DR: The performance of a multistage ozone/hydrogen peroxide (O3/H2O2) process was evaluated with respect to total organic carbon (TOC) removal of waste waters because rapid ozone consumption is required for the rapid formation of hydroxyl radical (HO*).
TL;DR: It is demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees, however, X-ray diffraction analysis was unable to confirm the oxalates profile for all products as described in the available commercial literature.
Abstract: In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.
TL;DR: It is demonstrated that citric and oxalic acid and the Aspergillus niger culture filtrates can bind Co 2+ and Zn 2- and in some cases, the culture Filtrates were more efficient than commercial organic acids.
Patent•
17 Jul 2001
TL;DR: In this article, a method of preparing a solution containing particles which contain titanium ions was proposed, where one or more hydrolysable titanium-containing compound(s) is stabilised by oxalic acid in a reaction medium.
Abstract: The invention relates to a method of preparing a solution containing particles which contain titanium ions wherein one or more hydrolysable titanium-containing compound(s) is stabilised by oxalic acid in a reaction medium. The reaction further relates to the preparation of titania materials (including particulate materials, coating solutions and films) which comprise or include anatase phase titania, and so are suitable in photocatalytic applications. The invention also deals with a method of preparing B-phase titania.
TL;DR: The interaction of the compounds affected cotyledon emergence and root length more negatively than germination and cotYledon length, and there was an enhancement in the phytotoxic activity, accentuating the effect of the other allelochemicals.
Abstract: Eleven allelochemicals (ferulic acid, cinnamic acid, 4-hydroxybenzoic acid, hydroxycinnamic acid, methyl propionate, oxalic acid, methylmalonic acid, p-anisic acid, butyric acid, 3-hydroxybutyric acid, and azulene) were identified in the exudate of Cistus ladanifer L. We studied the effect of each on germination, cotyledon emergence, root length, and cotyledon length of Rumex crispus. Three groups were distinguished with respect to phytotoxic activity: compounds with low activity (ferulic acid, 4-hydroxybenzoic acid, oxalic acid, methylmalonic acid, p-anisic acid, hydroxybutyric acid, and azulene), with intermediate activity (cinnamic acid and hydroxycinnamic acid), and with high activity (methyl propionate and butyric acid). The effect of the interaction of the compounds was studied. When acting conjointly, all combinations tested produced a more negative effect on both germination and seedling growth than when acting alone. The interaction affected cotyledon emergence and root length more negatively than germination and cotyledon length. When hydroxycinnamic acid and cinnamic acid were added to these mixtures there was an enhancement in the phytotoxic activity, accentuating the effect of the other allelochemicals.
TL;DR: The results lead to the mechanistic hypothesis that during the heterogeneous Fenton process, the cleavage of the PVA-chains may occur at random positions, the reactive centres being located inside the iron(III)-doped zeolite Y photocatalysts.
TL;DR: The main conclusion derived from this work is that a scheme of competitive kinetics describes only those cases in which one of the components is weakly or nonadsorbed on TiO2, whereas for two photolytes with high affinity for the surface cooperative effects may occur.
Abstract: Processes that occur in the TiO2-photocatalysis of binary aqueous solutions containing model photolytes with different affinity for the TiO2 surface (methanol and oxalic and salicylic acids) are analyzed from the photoelectrochemical response of TiO2 films under bias in a time window of 1-100 s. Long-lived oxidized intermediates produced upon illumination at 0.6 VSCE are detected by cathodic sweep run in the dark after irradiation. The main conclusion derived from this work is that a scheme of competitive kinetics describes only those cases in which one of the components is weakly or nonadsorbed on TiO2, whereas for two photolytes with high affinity for the surface cooperative effects may occur. The methanol-oxalate system is quantitatively modeled by considering that oxalate forms surface complexes with different reactivity and a parallel pathway for hole transfer to -OH and adsorbed oxalate. In this case as well as for electrolytes containing methanol and salicylate photooxidation of methanol (with low affinity for the surface) via intermediates formed by reaction with trapped holes (-*OH) is partially or fully suppressed. For electrolytes containing oxalic and salicylic acids in which both components chemisorb on TiO2 the photoelectrochemical response depends on preadsorption, the photooxidation pathways deviates those of single component systems, and there is remotion of salicylate adsorbed byproducts assigned to cooperative effects.
TL;DR: It is suggested that the competition between phosphate and organic acids relied on their relatively affinity to soil mineral surface at different conditions.
TL;DR: It is hypothesized that crystal retention within the nephron, and the subsequent development of a kidney stone, may result when the number or composition of these cell surface molecules is modified by genetic alterations, cell injury, or drugs in tubular fluid.
TL;DR: A complete study on the photocatalytic degradation of ethylenediaminetetraacetic acid over TiO2 has been initiated, to establish the influence of several parameters on the reaction rate, the nature of the intermediates and the kinetic regime.
TL;DR: The pattern of dysmorphogenesis with all compounds including EG showed a general embryotoxicity with diffusely distributed cell necroses with no specific target tissues selectively affected, emphasizing the hypothesis that the metabolites and not ethylene glycol itself are responsible for the embryot toxicity of ethylene Glycol in rats.
TL;DR: Slight but significant differences in toxicity of oxalic acid were found among mites from different brood stages; the median lethal density for mite from pupae with white eyes was 1.49 μg/cm 2 .
Abstract: The toxicity of oxalic and citric acid to Varroa destructorAnderson and Trueman was stud- ied with a laboratory assay. A contact test was used for the bioassay. Capsules were sprayed with solu- tions of the acids in a Potter tower and allowed to dry. Slight but significant differences in toxicity of oxalic acid were found among mites from different brood stages; the median lethal density for mites from pupae with white eyes was 1.49 μg/cm 2 . Citric acid was less toxic than oxalic acid. The addi- tion of sucrose to oxalic acid made the material more hygroscopic and the mortality of the mites increased at 75% R.H. Glycerol showed a similar synergic activity irrespective of relative humidity. Varroa destructor / bioassay / oxalic acid / citric acid / sucrose / glycerol / synergism
TL;DR: Using this antioxidative solution, the monoamine neurotransmitters and their metabolites could be determined with an automated LC assay even at room temperature, and the long-term stability of the analytes was still enhanced when acetic acid and L-cysteine were included in the solution.