High Concentration Of Oxalic Acid Research Articles

Evaluation of the deteriorating effects of microbial primary metabolites on silk fibres.

The silk biodegradation process remains unclear and requires elucidation with advanced analytical tools. To address this challenge, the role of microbial primary metabolites in the deterioration of ancient silk was investigated using metabolomics and proteomics techniques in this work. The oxalic and palmitic acids were separately identified as the most abundant organic and fatty acid metabolites for silk-fabric deterioration via metabolomics. Proteomics showed that oxalic acid accelerated the degradation of silk proteins, revealing changes at the molecular level in silk. A high concentration of oxalic acid promoted the dissolution of peptides by activating the cleavage activity of various amino acids on the molecular chain of silk protein. Palmitic acid formed sedimentary particulate matter with peptides solubilised from silk proteins, indicating the possibility that traces of ancient-silk proteins remained in the fatty acids. The work presented new techniques and concepts for studying the degradation of historical fabrics and contributed to the proposal of effective measures to prevent microbial attack on silk.

Effect of oxalic acid on the corrosion of 6063 aluminum alloy in ethylene glycol-water solution in presence of ammonium alcohol polyvinyl phosphate

The corrosion behavior of 6063 aluminum alloy in glycol-water solution with different concentrations of oxalic acid under different temperatures and the inhibitve effect of ammonium alcohol polyvinyl phosphate (AAPP) on its corrosion were investigated by weight loss experiment, electrochemical measurements and scanning electron microscopy (SEM). The results showed that low concentration of oxalic acid had a certain inhibitory effect on the corrosion of 6063 aluminum alloy in glycol-water solution, but high concentration of oxalic acid accelerated its corrosion. AAPP was a mixed type corrosion inhibitor with a predominantly anodic inhibition for 6063 aluminum alloy in a ethylene glycol-water solution containing oxalic acid, its corrosion inhibition efficiency was up to 90% at a concentration of 0.5 g/L under 30 ℃. The effect of AAPP on the surface of 6063 aluminum alloy obeyed the Langmuir isotherm equation. And the corrosion inhibition of AAPP for 6063 aluminum alloy was further confirmed by the results of weight loss experiment and SEM.

Excessive Oxalic Acid Secreted by Sparassis latifolia Inhibits the Growth of Mycelia during Its Saprophytic Process.

Sparassis latifolia is an edible and medicinal mushroom in Asia commercially cultivated on substrates containing pine sawdust. Its slow mycelial growth rate greatly increases the cultivation cycle. In this study, we mainly studied the role of oxalic acid (OA) secreted by S. latifolia in its saprophytic process. Our results show that crystals observed on the mycelial surface contained calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) according to X-ray diffraction (XRD). Vegetative mycelia secreted large amounts of OA during extended culture periods. However, high concentrations of OA decreased the mycelial growth rate significantly. Moreover, the degradation of lignocellulose was significantly inhibited under high concentrations of OA. These changes could be attributed to the significantly decreased activities of lignocellulose-degrading enzymes. In conclusion, by establishing a link between OA secretion by the mycelium and the slow growth rate of its saprophytic process, this work provides fundamental information for shortening the cultivation cycle of S. latifolia.

Bacillus-Secreted Oxalic Acid Induces Tomato Resistance Against Gray Mold Disease Caused by Botrytis cinerea by Activating the JA/ET Pathway.

Bacillus spp. are known for their ability to control plant diseases; however, the mechanism of disease control by Bacillus spp. is still unclear. Previously, bacterial organic acids have been implicated in the process of disease suppression. We extracted the total organic acid from Bacillus cereus AR156 culture filtrate and identified oxalic acid (OA) as the programmed cell death-inducing factor. OA strongly suppressed the lesion caused by Botrytis cinerea without significant antagonism against the fungus. Low concentration of OA produced by Bacillus spp. inhibited cell death caused by high concentrations of OA in a concentration- and time-dependent manner. Pretreatment with a low concentration of OA led to higher accumulation of active oxygen-scavenging enzymes in tomato leaves and provoked the expression of defense-related genes. The activation of gene expression relied on the jasmonic acid (JA) signaling pathway but not the salicylic acid (SA) pathway. The disease suppression capacity of OA was confirmed on wild-type tomato and its SA accumulation-deficient line, while the control effect was diminished in JA synthesis-deficient mutant, suggesting that the OA-triggered resistance relied on JA and ethylene (ET) signaling transduction. OA secretion ability was widely distributed among the tested Bacillus strains and the final environmental OA concentration was under strict regulation by a pH-sensitive degradation mechanism. This study provides the first systematic analysis on the role of low-concentration OA secreted and maintained by Bacillus spp. in suppression of gray mold disease and determines the dependence of OA-mediated resistance on the JA/ET signaling pathway. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2022.

One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions

Black mineral sands are widely used to obtain titanium dioxide, titanium, and, more recently, a variety of iron–titanium oxide nanostructures. Highly corrosive mineral acids or alkalis are commonly employed for this purpose. Hence, it is desirable to find eco-friendly ways to process these minerals, deriving high-added value materials. In this study, an Ecuadorian mineral sand precursor (0.6FeTiO3∙0.4Fe2O3 solid solution) was treated with oxalic acid aqueous solutions under subcritical water conditions. The synthesis was conducted in a batch reactor operating at 155 °C, 50 bar, and 700 rpm for 12 h, varying the oxalic acid concentration (0.1, 0.5 to 1.0 M). The as-obtained compounds were physically separated, dried, and analyzed by X-ray powder diffraction, scanning electron microscopy, and Raman spectroscopy. The characterization showed that the precursor was completely converted into two main products, ferrous oxalate, and titanium dioxide polymorphs. Rutile was always found in the as-synthesized products, while anatase only crystallized with high oxalic acid concentrations (0.5 and 1.0 M). These results open the possibility to develop more sustainable routes to synthesize iron and titanium-based materials with promising applications.

Oil palm trunk biomass pretreatment with oxalic acid and its effect on enzymatic digestibility and fermentability

Abstract Oil palm trunk biomass (OPTB) is a promising lignocellulosic resource for bioconversion due to its abundant availability, low cost and high carbohydrates content. In the present work, oxalic acid was used to pretreat OPTB under different pretreatment conditions. We maintained the same pretreatment severity value by manipulating the reaction time over a range of oxalic acid concentrations. The impact of oxalic acid pretreatment was evaluated in terms of xylose recovery, enzymatic digestibility as well as fermentability of Actinobacillus succinogenes 130Z for the production of industrially valuable succinic acid. Our findings demonstrated that oxalic acid at 4% (w/v) concentration showed superior effectiveness in solubilising hemicellulose from OPTB, achieving 60.3% xylose recovery. During enzymatic hydrolysis, again, the OPTB pretreated with 4% (w/v) oxalic acid exhibited the highest enzymatic digestibility of 63.4% yielding 39.1 g of sugar per 100 g OPTB. However, it was found that high concentration of oxalic acid (3–4%, w/v) inhibited A. succinogenes 130Z fermentation. The results reported herein suggest that the pretreatment using low oxalic acid (1%, w/v), though requiring longer reaction time, is preferable for an improved succinic acid production from OPTB.

Fate of oxalic-acid-intervened arsenic during Fe(II)-induced transformation of As(V)-bearing jarosite

Jarosite is a metastable Fe(III)-oxyhydroxysulfate mineral that can act as an excellent scavenger for arsenic (As) in acid sulfate soils (ASSs) and in areas polluted by acid mine drainage (AMD). The Fe(II)-induced transformation of jarosite can influence the As mobility in reducing soil and sediment systems. Although organic acids are prevalent in these environments, their influence on the behavior of As during the Fe(II)-induced transformation of jarosite is yet to be fully understood. In this study, we investigated the effects of oxalic acid on the partitioning of As into dissolved, adsorbed, poorly crystalline, and residual phases during the Fe(II)-induced transformation of As(V)-bearing jarosite at pH 5.5 and 1 mM Fe(II) concentration. The results demonstrated that jarosite frequently transformed to lepidocrocite in treatments without oxalic acid or with low oxalic acid (0.1 mM), and As was typically redistributed in the surface-bound exchangeable and residual phases. While a high concentration of oxalic acid (1 mM) retarded the transformation of jarosite and produced goethite as the primary end product, it also changed the Fe(II)-induced transformation pathway and drove most As into the residual phase (approximately 92%). The results indicated that oxalic acid exerts a significant influence on the partitioning and speciation of As during the above-mentioned transformation. X-ray photo electron spectroscopy analysis of the reaction products also revealed that As(V) may be still the dominant redox species. Overall, this study provides critical information for understanding the fate of As during the transformation of secondary minerals under complex influencing factors, thereby assisting in more accurately predicting the geochemical cycling of As in natural systems.

Effects of root exudates on the sorption of polycyclic aromatic hydrocarbons onto biochar

ABSTRACTThe effect of oxalic acid on phenanthrene sorption was varied from that on pyrene sorption. 1.0 mg L-1 of oxalic acid inhibited phenanthrene sorption, whereas 20, 50 and 100 mg L-1 of oxalic acid enhanced the sorption. However, pyrene sorption onto biochar was all inhibited among different concentrations of oxalic acid. New functional groups and increased polarity were observed in the biochar coexisted with oxalic acid, moreover, a high concentration of oxalic acid led to an increased specific surface area of the biochar. These changed factors contributed to biochar sorption to phenanthrene, which was dominated by surface adsorption. Weakened aromaticity and increased release of dissolved organic carbon from biochar may have been the main reason for inhibited pyrene sorption onto biochar by oxalic acid. Therefore, this study suggested that root exudates could greatly influence the sorption behavior of biochar towards PAHs in soil rhizosphere, which deserves attention in agricultural systems.

Nutritional value and fermentation characteristics of silage made from hybrid Rumex patientia L. x Rumex tianschanicus A.Los (Rumex OK 2) in different months during the year

Nutritional value and fermentation characteristics of silage made from hybrid Rumex patientia L. x Rumex tianschanicus A.Los (Rumex OK 2) in different months during the year

Effect of carboxylic acids on the properties of zerovalent iron toward adsorption and degradation of trichloroethylene

Zerovalent iron (ZVI) based technology has been applied to remediate contaminated groundwater and has been paid great attention as an economic alternative. But it is still remains highly challenging to remove chlorinated pollutants such as trichloroethylene (TCE) with ZVI. Low molecular weight carboxylic ligands (formic acid (FA), oxalic acid (OA), and citric acid (CA)) were chosen to study the influence on the performance of ZVI in groundwater, including the morphology of Fe surface and the Fe dissolution. The removal rate of TCE with ZVI in the presence of 30 mM carboxylic groups followed an order of FA > OA > pure water ≅ CA. FA provides protons to promote the surface corrosion and generated more magnetite on the ZVI surface, which was further responsible for a high adsorption of TCE. With the strong complexing ability of OA and CA, passive layers could form dissoluble complexes via a ligand-promoted dissolution process. However, high concentration of OA resulted in Fe oxalate reprecipitated back onto the ZVI surface then inhibited the reactivity of ZVI. The Fe-ligand complexes also have ability to transform TCE depending on their redox properties. It is expected that effectiveness of carboxylic ligands on the ZVI: those low molecular weight carboxylic ligands in groundwater and soil may enhance the reaction efficiency of ZVI by altering the surface characteristics of ZVI. Therefore, the carboxylic ligands could increase the reactivity and the longevity of ZVI.

Effect of Frequency on Structure of Porous Alumina Formed By Indirect Oxidation

In general, industrial anodization based on direct current or alternating current (AC) electrolysis can be applied to the surface treatment of large-sized and long aluminum products such as building materials. However, conventional anodization is unsuitable for the simultaneous surface treatment of a large number of small components including fine particles because direct conduction between the aluminum anode and the cathode is essential for completing the electrical circuit. Recently, we proposed new surface treatment method, i.e., indirect oxidation and investigated the influences of electrolysis conditions such as voltage, frequency, reaction time, concentration of electrolyte, and temperature on the growth of porous oxide film [1]. In our previous study, high-purity (99.99 %) aluminum sheets with a working area of 10 cm2 and aluminum particles (99.5 %) of 3 mm diameter were used as processing objects. In the case of AC electrolysis in 8 mmol dm−3 oxalic acid at 20 °C, 60 VM, and 150 Hz, which were the base condition in this study, the current density was approximately 100 A m−2. When AC electrolysis was conducted at higher temperatures and voltages using a high concentration of oxalic acid compared with that in the base condition, a high current density in the 120–200 A m−2range was observed. Frequency had relatively small effect on current density. Even in the indirect oxidation, we observed that the relationship between the film thickness and the AC electrolysis time was approximately linear. We also used aluminum particles as a processed material to demonstrate the versatility of the indirect-oxidation-based surface treatment [1]. After indirect oxidation for 240 min under the base condition, the treated aluminum particles were immersed in dye solution. The dye was absorbed in porous alumina films over the entire surface of the aluminum particles. This result indicates that the porous films were uniformly and simultaneously formed on aluminum particles, i.e., the present technique can accommodate a wide variety of particle shapes and sizes with high throughput and low costs. In this study, we carry out a preliminary study to investigate the effect of frequency on the structure of porous alumina formed by indirect oxidation. We mainly focus on the difference between the proposed method and conventional AC anodization. The correlation between the cell dimensions and applied voltage will be also discussed. [1] H. Asoh, M. Ishino, H. Hashimoto, RSC Adv., 6, 90318 (2016).

Periodic Precipitation Patterns during Coalescence of Reacting Sessile Droplets.

The coalescence behavior of two sessile drops that contain different chemical reactants (cerium nitrate and oxalic acid) and its impact on the formation of the solid precipitate (cerium oxalate) are investigated. With different liquids, the surface tension difference in the moment of drop-drop contact can induce a Marangoni flow. This flow can strongly influence the drop-drop coalescence behavior and thus, with reacting liquids, also the reaction and its products (through the liquid mixing). In our study we find three distinctly different coalescence behaviors ("barrier", "intermediate", "noncoalescence"), in contrast to only two behaviors that were observed in the case of nonreacting liquids. The amount of liquid mixing and thus the precipitation rate are very different for the three cases. The "intermediate" case, which exhibits the strongest mixing, has been studied in more detail. For high oxalic acid concentrations, mainly needle-like aggregates, and for low concentrations, mainly flower-like precipitate morphologies are obtained. In a transition range of the oxalic acid concentration, both morphologies can be produced. With the applied coalescence conditions, the different aggregate particles are arranged and fixed in a precipitate raft in a regular, periodic line pattern. This confirms the drop-drop coalescence configuration as a convection-reaction-diffusion system, which can have stationary as well as oscillatory behavior depending on the system parameters.

Effect of oxalic acid concentration on the magnetically enhanced capacitance and resistance of AAO humidity sensor

The enhanced capacitance and resistance behavior of anodic aluminum oxide (AAO) humidity sensor by both the high concentration of oxalic acid and applied magnetism has been investigated. At low relative humidity (RH, ≤45%), the enhanced capacitance response from high concentration of oxalic acid was attributed to phonon-assisted electron tunneling mechanism that was promoted by more acid anions within the AAO pore wall and barrier layer. The other enhancement from magnetic addition was due to the magnetic field induced more orderly arrangement of water molecules for higher capacitance. At high RH (>45%), the capacitance of AAO sensors at different acid concentrations (0.3–0.7M) with magnetic field was larger than that without magnetic field under the same mechanisms at low RH. Moreover, the medium-concentration AAO sensor exhibited the highest capacitance at RH over 60% due to the enhanced sensing surface area and pore conductance. The short and reliable capacitance response/recovery time was also obtained from the high-concentration AAO sensor under presence or absence of a magnetic field. In addition, the applied magnetism can significantly enhance the ordinary magnetoresistance response of humidity sensors at different acid concentrations at low-to-high RH for more linear-like relationship between the resistance and RH.

Effect of environmental factors and precursors on oxalic acid production, mycelial biomass and virulence of a potential bioherbicide isolate of Sclerotium rolfsii SC64 produced in liquid culture

The fungus Sclerotium rolfsii is presently under development as a bioherbicide for broadleaf weed species using fungus-infested substrates as application material in this laboratory. The effect of environmental factors and three precursors (citric acid, ascorbic acid, and sodium succinate) on mycelial growth, oxalic acid production, and virulence by SC64 in liquid culture were investigated. The results showed that for mycelia growth the optimum liquid medium was Modified Richard's solution (MRS) among the five tested media, but potato dextrose broth (PDB) produced the maximum oxalic acid production and virulence on detached Solidago canadensis leaves. When PDB was used as the basic medium, the oxalic acid/mycelial dry weight (mg g–1) ratio reached the peak 4 days after inoculation. The optimum temperature for oxalic acid production was at 27°C, but increased mycelial dry weight and virulence were observed at 30°C. The optimum range of initial pH value for oxalic acid accumulation was 4.0–6.0, with the optimal pH 5.0; highest mycelial growth was with an initial pH 3.5–6.0 (optimum pH 5.0) and subsequently pH 3.5–5.5 (maximum at pH 3.5). Both mycelial dry weight and oxalic acid production showed a decreasing trend as a result of the precursor of oxalic acid being added to PDB. Among the three precursors, the greatest decrease in mycelial dry weight, and oxalic acid production was caused by sodium succinate. This clarification of optimal conditions for production of mycelial biomass while insuring high concentrations of oxalic acid and high virulence should be useful for further development of this fungus as biocontrol agent.

Distribution of Fe(II) Concentration during Degradation of Rhodamine B by Fenton Reagent

The effects of reaction conditions including Fe2+, H2O2, oxalic acid, and humic acid dosages were discussed on the Fenton degradation of rhodamine B (RB). The optimal reaction conditions of Fenton reaction were 0.15 mM Fe2+, 5 mM H2O2, and pH 3.0, and the decolorization rate RB (10 mg/L) reached 97.8% after 30min catalytic degradation. The changes of Fe2+concentrations in Fenton system has been focused on in this work. A relatively low concentration of Fe2+was maintained during reaction process when Fe2+and H2O2were added with high concentration, and thus RB was degraded quickly. The results implicated that Fe2+dosage played a very important role in the degradation of RB, and H2O2dosage didn’t have an apparent influence on the degradation of RB in general. The Fenton degradation of RB could be inhibited in the presence of oxalic acid and humic acid, especially at a high concentration of oxalic acid and humic acid.

The effect of acetylsalicylic acid and oxalic acid on Myzus persicae and Aphidius colemani

AbstractPlants can respond to damage by pests with both induced direct defences and indirect defences by the attraction of their natural enemies. Foliar application of several plant‐derived chemicals, such as salicylic acid and oxalic acid, can induce these defence mechanisms. The effect of acetylsalicylic acid and oxalic acid on the aphid Myzus persicae Sulzer (Homoptera: Aphididae) and its parasitoid Aphidius colemani Viereck (Hymenoptera: Aphidiidae) was investigated. Experiments were carried out with direct application of acetylsalicylic and oxalic acids on these insects, as well as choice and no‐choice tests using foliar application of both chemicals on Brussels sprouts plants, Brassica oleracea var. gemmifera L. (Brassicaceae). Parasitoids were given a choice between treated and untreated plants for oviposition, and the effects of the chemicals on aphid and parasitoid development were determined. Although direct application of both chemicals increased aphid mortality, their foliar application did not induce resistance against aphids. The foliar application of such compounds, even in low concentration as shown in the choice tests, has the potential to induce indirect plant defences against aphids by encouraging aphid parasitisation. Although the direct application of both chemicals reduced parasitoid emergence from their hosts, the foliar application of acetylsalicylic acid and low concentrations of oxalic acid did not have a negative effect on parasitoid emergence ability. However, 10 mm oxalic acid reduced the number of emerged parasitoids in no‐choice experiments. This study shows that foliar application of acetylsalicylic and oxalic acids has the potential to encourage aphid parasitisation, but care is needed as high concentrations of oxalic acid can have a negative effect on these beneficial organisms.

Toxic and signalling effects of oxalic acid

Oxalic acid is thought to be a key factor of the early pathogenic stage in a wide range of necrotrophic fungi. We have recently published that oxalic acid induces Programmed Cell Death (PCD) in Arabidopsis thaliana cells. This cell death results from an early anionic efflux which is a prerequisite for the synthesis of ethylene and the PCD. Complementary experiments have been carried out by using seedlings of A. thaliana. The effects of millimolar concentrations of oxalic acid were analysed on A. thaliana seedlings. A treatment with a 3 mM oxalic acid solution does not alter the development of the plants but induces the transcription of defence related genes which are anion channel dependant. Moreover, our results suggest that a pre-treatment of the seedlings with oxalic acid is able to confer the resistance of A. thaliana against Sclerotium rolfsii. Regarding our results, we suggest that oxalic acid plays two distinct roles, depending on the concentration: a high concentration of oxalic acid induces a large PCD and then contribute to the progression of the fungi. However, at low concentration it is able to induce the establishment of a resistance of the plant against the fungi.Addendum to: Errakhi R, Meimoun P, Lehner A, Vidal G, Briand J, Corbineau F, Rona JP, Bouteau F. Anion channel activity is necessary to induce ethylene synthesis and programmed cell death in response to oxalic acid. J Exp Bot 2008; doi:10.1093/jxb/ern166.

Does the degree of pectin esterification influence aluminium sorption by the root apoplast?

This study investigates the influence of the degree of pectin esterification (DE) on the sorption of aluminium (Al) by plant roots. Ca-pectates, with varying degrees of esterification, are major constituents of the soil–root interface and of the root apoplast. Ca-pectate networks (Ca–PG and Ca–Al–PG) were formed at three DEs (0%, 26%, 65%) with custom-made cells and used as a model system for the root cell wall. Sorption of Al was conducted for 24 h at a range of oxalic acid concentrations (0–500 μM) at pH 4.50 to examine two different metal resistance mechanisms of plants. In fact, plants release organic acids either to desorb or to complex metals to prevent their sorption by plant roots.Thermal analysis showed that Al sorption did not seem to affect the stability of the pectate gels and the presence of hydrophobic groups (–CH3) at DE > 0% seemed to even increase the stability of the gels decreasing thermal decomposition. Results suggest two potential Al tolerance mechanisms: (a) high oxalic acid concentrations (500 μM) were able to desorb almost 100% and 72% at DE 65 and 0%, respectively; (b) high oxalic acid concentrations (500 μM) and thus molar ratios of 5:1 (oxalate/Al) reduced Al sorption by 98% and 86% at DE 65 and 0%, respectively. In conclusion, both mechanisms indicate that high degrees of esterification as 65% are much more efficient in excluding Al from the apoplast and might therefore contribute to Al resistance in plants.

Involvement of FpTRP26, a thioredoxin-related protein, in oxalic acid-resistance of the brown-rot fungus Fomitopsis palustris

Brown-rot fungus Fomitopsis palustris grows vigorously at high concentrations of oxalic acid (OA), which is fungal metabolite during wood decay. We isolated a cDNA FpTRP26 from F. palustris by functional screening of yeast transformants with cDNAs grown on plates containing OA. FpTRP26 conferred a specific resistance to OA on the transformant. OA-content in transformants grown with 2 mM OA decreased by 65% compared to that of the control. The amount of FpTRP26 transcript in F. palustris amplified with increasing OA-accumulation, and was maintained at high levels even in the stationary phase. Its transcription in F. palustris was inducible in response to exogenously added OA. These results suggest that FpTRP26 is involved in the OA-resistance in F. palustris.

Deposition of Titanium−Vanadium Oxide Thin Films on Organic Self-Assembled Monolayers: Role of Complexing Agents

Titanium−vanadium oxide films were co-deposited from aqueous solutions on organic self-assembled monolayers (SAMs) with alkylammonium or amine surface functional groups. The chemical composition of the films was manipulated via the use of lactic acid and oxalic acid as complexing agents. From solutions with [oxalate]:[vanadium] < 1:1, titanium-enriched films were formed. However, with [oxalate]:[vanadium] > 1:1, the Ti:V ratio dropped back to that of films deposited in the absence of complexing agents. Therefore, it is concluded that oxalic acid chelates both titanium and vanadium, but preferentially vanadium. At high concentrations of oxalic acid, no films formed, indicating that both titanium and vanadium were chelated strongly. Lactic acid, in contrast, was oxidized by pentavalent vanadium. When [lactate]:[vanadium] < 1:2, the resulting V4+ increased the deposition rate of vanadium, and vanadium-rich films were formed. For [lactate]:[vanadium] > 1:2, the remaining (i.e., unoxidized) lactic acid preferentially complexed vanadium and showed effects comparable to those seen with oxalic acid. The thickness of films formed on the alkylammonium SAMs increased with increasing vanadium content in the films, whereas film composition had little or no effect on the thickness of films formed on amine SAMs.