Oxalic Solution Research Articles

Recycling Nd Magnet Scraps to Synthesize Carbon‐Swaddled Fe3O4 Anode Material for Lithium‐Ion Battery

This study explores the innovative recycling of neodymium (Nd) permanent magnet scrap to synthesize Fe3O4, a high‐capacity anode material for secondary batteries, by leveraging the Fe oxalate solution produced during recycling. The traditional process of recovering Fe from permanent magnets in the form of oxides produces products with limited economic viability and usability. For the first time, we have successfully synthesized Fe3O4 as an anode material for lithium‐ion (Li‐ion) secondary batteries from scrap Nd magnets. We address the existing challenge by employing a novel approach: hydrothermal synthesis of crystalline FeC2O4·2H2O from the Fe leachate, extracted via oxalic acid leaching from a mixed phase of NdF3‐Fe2O3 controlled during fluorination heat treatment while recycling. The recovered FeC2O4·2H2O is subsequently phase‐transferred to Fe3O4 under an Ar atmosphere. To overcome the inherent low conductivity and rate capability of Fe3O4, a carbon‐coating process utilizing dopamine HCl is implemented. The developed C‐Fe3O4 anode material exhibits a significant capacity retention of 428 mAh/g after 500 cycles at 1C, showcasing its potential for use in high‐performance secondary batteries and contributing to the sustainable recycling of critical materials.

Enhancing anti-corrosion performance of anodic film on aluminum-lithium alloy AA2099-T83 by post-treatment in lithium oxalate solutions near room temperature

Enhancing anti-corrosion performance of anodic film on aluminum-lithium alloy AA2099-T83 by post-treatment in lithium oxalate solutions near room temperature

Antiurolithic activity of Zaleya pentandra (L.) C Jeffrey in ethylene glycol-induced calcium oxalate crystal rat model; A scientific validation of traditional use for kidney stone prevention

Ethnopharmacological relevanceTraditional herbal remedies have been used for treating nephrolithiasis, but the relevant scientific evidence is limited. Zaleya pentandra (L.) C. Jeffrey is traditionally used for the prevention of kidney stones in various cultures. However, its efficacy has not been scientifically studied. Aim of the studyThis study aimed to investigate the antiurolithic activity of Zaleya pentandra, and validate its traditional used for preventing kidney stones. Materials and methodsThe crude ethanolic extract of Z. pentandra (Zp.Crd) was evaluated through in vitro and in vivo studies. In vitro experiments assessed its impact on crystal count and morphology in metastable calcium oxalate solutions. In vivo studies involved diuretic and ethylene glycol-induced calcium oxalate crystal formation in male Wistar rats. ResultsZp.Crd transforms calcium oxalate crystals from harmful calcium oxalate monohydrate (COM) to calcium oxalate dihydrate (COD). In vivo, Zp.Crd exhibited dose-dependent (30–300 mg/kg) diuretic activity in rats by significantly increasing urinary sodium (Na+) and potassium (K+) excretion, similar to the standard diuretic hydrochlorothiazide (HCT). In the urolithiasis model, Zp.Crd exhibited dose-dependent antiurolithic effects by reducing kidney crystals and significantly altering lithogenic factors induced by ethylene glycol, including crystalluria, oxaluria, calcium, creatinine, and urea, in the urine and serum of treated rats. Zp.Crd also exhibited antioxidant effects, effectively combating oxidative lithogenic stress in rats. ConclusionZp.Crd has been shown to demonstrate antiurolithic activity against CaOx stones through CaOx crystal inhibition, diuretic activity, antioxidant properties, hypocalciuric effects, and hypercitrauric actions. The findings underscore Zp.Crd's potential as a viable alternative or supplemental therapy to current urolithiasis treatments, paving the door for further clinical trials and its inclusion into modern medical practices.

Dissolution process and mechanism of montmorillonite in oxalic acid and sulfuric acid media at various pH levels

The dissolution of silicate minerals plays a crucial role in many natural geological processes. In order to better comprehend the reaction mechanisms and dissolution characteristics of montmorillonite in different acidic systems, the effects of interfacial reactions of montmorillonite with oxalic and sulfuric acid solutions at various pH levels on the ionic dissolution, crystal structure, and micro-morphology were studied, and the morphology of aluminum and saturation index of secondary mineral were simulated. It was shown that the dissolution amounts of Mg2+, Al3+ and Si4+ in montmorillonite structure decreased with the increase of pH value, which reflected the dependence of montmorillonite dissolution on the pH value of solution. The dissolution percentages of Mg2+, Al3+ and Si4+ after the reaction of montmorillonite with oxalic acid solution were greater than those in sulfuric acid solution, and the highest dissolution rate of Al3+, indicated that both ligands and protons attacked the surface sites of montmorillonite and accelerated the dissolution of ions. Moreover, oxalate ligands exerted specific binding effects on Al3+ ions. While reacting with oxalate and sulfate, the tetrahedral, octahedral and interlayer cations of montmorillonite exhibited the non-stoichiometric and inconsistent dissolution. The oxalate ligands have a strong complexation effect on Al3+, so that Al3+ in oxalate solution exists in the form of aluminum oxalate complex, which reduces the effective concentration of Al3+ in solution and promotes the dissolution of Al3+ in montmorillonite structure. The Mg2+ ions settled at octahedral substitution sites possessed weak stability, while those from the interlayer featured strong interlayer interchangeability, demonstrating the dissolution percentage up to 10.85 % and 8.62 % even in oxalic and sulfuric acid solutions at pH of 6.5. All secondary mineral phases in the solution were undersaturated, making the montmorillonite dissolution difficult to balance. Montmorillonite has a high cation exchange capacity, which makes it have a strong buffer capacity to exogenous acids. This study helps to explain the dissolution process of montmorillonite in inorganic and organic acid solutions at different pH value.

COMPETITIVE ADSORPTION OF Fe2+, Pb2+, AND Zn2+ IONS FROM MULTI-METAL ION SOLUTION ON AMMONIUM OXALATE MODIFIED KAOLINITE CLAY

The competitive adsorption of Fe2+, Pb2+, and Zn2+ ions from mixed multi-metal aqueous solution on ammonium oxalate-modified kaolinite clay (AOK) was studied to determine the competitive influence of the metal ions on the adsorption of other metal ions. The kaolinite clay was modified by treating it with 0.2 M of ammonium oxalate solution at 50 oC. The adsorption of the metal ions was carried out using initial concentrations of 20, 35, and 50 mg L-1 in both the single and multi-metal ion solutions. The results revealed that at a low concentration of 20 mg L-1, the adsorption capacity for the uptake of the metal ions on AOK is non-competitive. At higher adsorbate concentrations of 35 and 50 mg L-1, the single to multi-metal ions equilibrium adsorption capacity ratio value obtained was less than 1. This indicated an antagonistic effect on competing for the adsorption site in the following order: Pb2+ (9.9 mg g-1) > Fe2+ (3.85 mg g-1) > Zn2+ (2.85 mg g-1). The outcome revealed that ammonium oxalate-modified kaolinite is a potential adsorbent for remediation of multi-heavy metal-laden wastewater with preferentially higher affinity for Pb2+ ions than other metal ions.

P098 CARDIAC REMODELING IN MICE TREATED WITH SODIUM OXALATE AND AORTIC STENOSIS

Background: Cardiovascular Diseases are one of the main global public health problems, with increasing mortality due to population aging and Hypertension (HTN). HTN is a risk factor for other diseases, such as aortic stenosis, renal dysfunction, and cardiac hypertrophy (CH). The hemodynamic overload caused by HTN affects the heart and kidneys, but the exact mechanisms of these alterations are not fully understood. Experimental models help study these mechanisms; however, a well-established model of CH with cardiorenal dysfunction does not yet exist. Objective: to evaluate whether the combination of cardiac hypertrophy, induced by transverse aortic constriction (TAC), and renal injury, induced by soluble sodium oxalate (OXA), can be a new model of CH with cardiorenal dysfunction. Methods: Male C57BL mice were randomized as follows: SHAM, receiving saline or OXA solution, and TAC, receiving saline or OXA solution. Echocardiography, direct blood pressure (BP) recording, metabolic cage, histology were performed to evaluate cardiac and renal function, hemodynamics, autonomic modulation, and baroreflex. Results: The TAC+OXA group showed the highest systolic BP(SBP) (SBP: SHAM: 122±5.24 vs. TAC+OXA: 160±5.24 mmHg, p<0.01), increased double product (DP) (DP: SHAM: 64.65±4.76 mmHg/bpm vs. TAC: 89.53±5.85 mmHg/bpm, p=0.02), significant reduction in autonomic modulation (RMSSD: OXA: 12.5±1.8 vs. TAC+OXA: 2.8±0.2 ms, p<0.01) and reflex tachycardia, eccentric hypertrophy, and worse renal function. The TAC group showed eccentric hypertrophy, increased BP variability (SD-SBP: SHAM: 2.97±0.07 mmHg vs. TAC: 5.63±0.57 mmHg, p≤0.01), diastolic dysfunction, and dilated left ventricle in diastole. The OXA group showed increased autonomic modulation and heart rate variability, renal damage characterized by inflammation, proximal tubule damage, and interstitial fibrosis when associated with TAC. All treated groups showed a significant reduction in reflex tachycardia. Conclusion: Transverse aortic constriction combined with OXA gavage is a model of CH with renal dysfunction, as the combination caused more significant renal damage, systemic hypertension, decreased autonomic modulation and baroreflex sensitivity, and eccentric hypertrophy with subsequent LV diastolic dysfunction.

Antimony sorption to schwertmannite in acid sulfate environments

Schwertmannite is a poorly-crystalline Fe(III) oxyhydroxysulfate mineral that may control Sb(V) mobility in acid sulfate environments, including acid mine drainage and acid sulfate soils. However, the mechanisms that govern uptake of aqueous Sb(V) by schwertmannite in such environments are poorly understood. To address this issue, we examined Sb(V) sorption to schwertmannite across a range of environmentally-relevant Sb(V) loadings at pH 3 in sulfate-rich solutions. Antimony K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Sb(V) sorption (at all loadings) involved edge and double-corner sharing linkages between SbVO6 and FeIIIO6 octahedra. The coordination numbers for these linkages indicate that sorption occurred by Sb(V) incorporation into the schwertmannite structure via heterovalent Sb(V)-for-Fe(III) substitution. As such, Sb(V) sorption to schwertmannite was not limited by the abundance of surface complexation sites and was strongly resistant to desorption when exposed to 0.1 M PO43-. Sorption of Sb(V) also conferred increased stability to schwertmannite, based on changes in the schwertmannite dissolution rate during extraction with an acidic ammonium oxalate solution. This study provides new insights into Sb(V) sorption to schwertmannite in acid sulfate environments, and highlights the role that schwertmannite can play in immobilizing Sb(V) within its crystal structure.

Offline constrained reinforcement learning for batch-to-batch optimization of cobalt oxalate synthesis process

The cobalt oxalate synthesis, a batch process, plays a crucial role in the refinement of cobalt metal. The mean particle size of cobalt oxalate is a critical indicator that reflects product quality. However, excessive ammonium oxalate solution flow can heighten waste disposal costs in the production process. To address these issues, we propose a novel offline reinforcement learning (RL) algorithm that guarantees compliance with constraints in the cobalt oxalate synthesis process, utilizing exclusively static datasets. This method employs cost critic networks to assess costs, transforming the constrained optimization problem into an unconstrained one by introducing Lagrangian multipliers. We use exponential moving average (EMA) to optimize the update of proportional integral derivative (PID) control multipliers, reduce overshoot and oscillation in the control process, and thus improve the overall stability of the system. Furthermore, to optimize algorithm performance, a deep residual network (DResNet) is integrated into the policy network. Experimental results indicate that the algorithm’s optimization policy performs significantly better under constraints.

CTAB-induced synthesis of two-dimensional copper oxalate particles: using l-ascorbic acid as the source of oxalate ligand.

Copper oxalate is typically synthesized through a precipitation reaction involving copper salts mixed with oxalic acid or oxalate solutions. However, in this study, we were successful in synthesizing well-formed square-like copper oxalate particles under liquid-phase conditions at ambient temperature and pressure using ascorbic acid as the source of the oxalic acid ligand. The addition of cationic surfactant cetyltrimethylammonium bromide (CTAB) caused the morphology of copper oxalate particles to undergo a transition from three-dimensional to two-dimensional. And the inhibition of the assembly of primary copper oxalate nanocrystals along the [001] direction became stronger with the increase of CTAB concentration. The impact of CTAB on the crystallization, growth, and self-assembly processes of primary copper oxalate nanocrystals was analysed using various testing methods. Based on these analyses, the possible mechanism of CTAB-induced synthesis of two-dimensional copper oxalate particles was finally proposed.

Bottle-in-bottle reaction device: Portable gas pressure meter for rapid and on-site analysis of oxalate in spinach and tea beverages

A gas pressure meter-based portable/miniaturized analytical kit was established for rapid and on-site detection of oxalate. Potassium permanganate (KMnO4) and oxalate solution were mixed together in bottle-in-bottle reaction device, a simple oxidation reaction process occurred within 6 min and carbon dioxide (CO2) was generated, inducing the pressure of the sealed bottle changed, which was measured by a portable gas pressure meter. A detectable range of 0.1–6 μmol mL−1 and a detection limit of 0.064 μmol mL−1 were achieved. The proposed analytical method was further used for the analysis of several real samples (spinach, beverages and water samples), with the recoveries of 89–111%. Considering the interferences from the complicated matrix, calcium chloride (CaCl2) was served as a precipitant, oxalate (C2O42−) was precipitated with Ca2+ to form precipitation (CaC2O4), CaC2O4 was then separated from the matrix by centrifuge/filter, eliminating the interferences. It is a rapid, easy-used and interference-free analytical system/device for oxalate on-site and real time analysis.

Design of a continuous ion exchange process in battery metals recycling: From single column experiments towards a simulated moving bed configuration

In hydrometallurgical recovery of LIB metals, ion exchange (IX) has hitherto played only a minor role. Separation experiments were conducted in single laboratory-scale IX columns with the aim of laying the foundation for a continuously operated multicolumn IX process similar to a simulated moving bed (SMB) configuration. In this study, the initial process developed earlier was improved by reducing the number of process steps and external streams. The desorption step with oxalate solution was examined in single-column batch experiments to ensure complete desorption of iron in the proposed continuous multicolumn IX process. Additionally, the volume flowrates were adjusted to achieve acceptable switch times of 25 min in an SMB configuration. It was found that the bead size of the resin is a critical factor in IX recovery of battery metals. The raffinate purity for the case of processing 2.5 BV lithium-ion battery waste leachate (LIBWL) improved from 97.2 % to 99.8 % when the resin bead size was reduced from 0.55 ± 0.05 mm to 0.4 ± 0.04 mm and a narrower bead size distribution. The LIBWL feed concentration was varied to mimic the dilution of fresh feed in an SMB set-up. The percentage recovery of Co and Ni decreased from 93.7 % and 96.6 % to 80.8 % and 89.4 %, respectively, when the LIBWL was diluted. This was a result of the decrease in concentration of impurity metals in the feed. Less impurity metals were sorbed and consequently, more ion exchange sites were available for the sorption of the target metals, which enhanced the retention of Co and Ni. The results were used to develop an IX column operation strategy and to suggest an initial SMB design. The multicolumn configuration presented in this work offers great potential for continuous production of high-purity Li, Ni and Co-containing raffinate (> 99.5 %).

The study of the chemical properties of gray tereskenes ceratoides latens

Today, perennial plants of the natural flora are a raw material resource for the production of drought-resistant and heat-resistant feeds, among which Eurotia Ceratoides occupies a special place. In this work, the chemical properties of Eurotia Ceratoides latens (J.F. Gmel) were studied, the humus content in the soil was determined, and the chemical and physico-chemical properties of light gray soil (humus, water, carbonate ions, nitrogen) were revealed. The humus content was determined based on the oxidation of organic carbon with chromic acid to carbon dioxide. The chemical composition of Eurotia Ceratoides Latens was analyzed for the content of nutrients in the plant (protein, fiber, fat, nitrogen-free extractables, ash) and water-soluble substances (C, CO2, Ca, Mg). It was found that the ash content in plants almost does not change in the phases of vegetation with the age of plants and ranges from 9,11-10,05%, respectively, and the calcium content was at the level of 3,67- 4,90. The content of «crude» fiber was determined using the Soxlet apparatus, the content of calcium cations in the soil was evaluated by the complexometric method, and the Kjeldahl method was used to determine crude protein, crude fat by ether extraction, nitrogen-free extractives in ash by precipitation with a saturated solution of ammonium oxalate, and phosphorus by the colorimetric method. The nutritional value of Eurotia Ceratoides latens has been revealed.

Efficient separation and comprehensive recovery of rare earth, bismuth and iron by one-step extraction and two-step stripping

A route was proposed to separate bismuth, iron, and rare earth elements from a solution containing nickel and magnesium through one-step extraction and two-step stripping. Firstly, saponified di-(2-ethylhexyl) phosphoric acid (D2EHPA) was used as the extractant to separate target elements. RE(III), Bi(III), and Fe(III) could be separated from Ni(II) and Mg(II), with extraction efficiencies of more than 99 %. Secondly, RE(III), Bi(III), and Fe(III) were stripped selectively by nitric acid and oxalic acid, respectively. Subsequently, the iron present in the oxalic acid stripping solution was treated under UV irradiation for 15 min to recover oxalic acid and obtain the ferrous oxalate product. The stripping efficiencies of RE(III), Bi(III), and Fe(III) were up to 100 % for four-stage countercurrent stripping, and the recovery rates of RE(III) and Bi(III) were 97.3 % and 99.2 %. The purities of nitrate rare earth enrichment solution, bismuth oxalate and ferrous oxalate were 99.7 %, 98.4 % and 99.5 %, respectively. In addition, the extraction dynamic demonstrated that the double salt precipitation was not observed during the extraction when the extraction time exceeded 7 min and the extraction mechanism was analyzed using the slope method. This process shortens steps, and is more efficient to separate RE(III), Bi(III), and Fe(III) from the mixed solution containing Ni(II) and Mg(II), which has a prospective industrial application.

Preparation of high performance calcium oxalate protective film by multifunctional organic molecule on carbonate stones in dry environment

Preparation of calcium oxalate film has been widely adopted in the protection of carbonate stone. However, the solution of oxalate acid or its derivative brushing on the carbonate stone usually evaporates quickly in dry environment, resulting in the inability to form a complete covering calcium oxalate film. Although expensive and difficult to operate, water retention procedures such as surface poultice and plastic wrap are often needful in this case. A novel method for the preparation of the calcium oxalate film with no need of water retention procedures was developed in this paper. The morphology, structure and performance of the calcium oxalate film prepared by above method were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), infrared spectroscopy (IR), X-ray diffraction (XRD), wetting angle, acid resistance, surface strength, porosity, water absorption and color difference. The experimental results showed that a calcium oxalate film with high performance can be prepared in dry environment when ethylene glycol was added into the oxalate acid solution as water retention agent even and the traditional water retention procedures are not necessary. This new method is of great enlightening significance for the protection of the immovable carbonate stones in the dry environment.

Advanced mapping of inorganic treatments on porous carbonate stones by combined synchrotron radiation high lateral μXRPD and μXRF

Understanding the effects of consolidating inorganic mineral treatments on carbonate stones of cultural heritage, and on the nature and distribution of newly formed products within the matrix, poses a significant challenge in Heritage Science and Conservation Science. Existing analytical methods often fail to deliver spatial and compositional insights into the newly formed crystalline phases with the appropriate high lateral resolution. In this study, we explore the capabilities and limitations of synchrotron radiation (SR) micro-X-ray powder diffraction (μXRPD) mapping combined with micro-X-ray fluorescence (μXRF) to give insight into compounds formed following the application of ammonium oxalate (AmOx) and diammonium phosphate-based (DAP) solutions on porous carbonate stone. Ultimately, the integration of μXRPD mapping and μXRF analysis proved itself a powerful asset in providing precise qualitative and quantitative data on the newly formed phases, in the case of both calcium oxalates (CaOxs) and calcium phosphates (CaPs), and their complex stratigraphic distribution, thus opening a new route for applications to a more comprehensive study of inorganic treatments applied to carbonate substrates.

IN VITRO INVESTIGATION OF ANTIOXIDANT AND ANTI-UROLITHIATIC ACTIVITY OF HOMONOIA RETUSA ROOTS

Ayurvedic practitioners utilise Pashanabheda as an anti-urolithiatic. The root of Homonoia retusa (Euphorbiaceae), which grows in the Indian town of Tirupathi, was chosen for this study's screening for its antioxidant and anti-urolithiatic properties. The hydrogen peroxide assay (H2O2), ferric reducing antioxidant power (FRAP), and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) techniques were utilised to assess antioxidant activity. The anti-urolithiatic activity was evaluated by nucleation and aggregation assay by adding 0.01 M sodium oxalate solutions that caused the crystallisation of Calcium oxalate. By measuring turbidity in the presence or absence of extract at 620 nm using a spectrophotometer, the effect of extract (200, 400, 600, 800, and 1000 µg/ml) was investigated. According to the result, aqueous root extract can prevent crystal growth and aggregation more than methanol-based root extract.

High-Selectivity Recycling of Valuable Metals from Spent Lithium-Ion Batteries Using Recyclable Deep Eutectic Solvents.

The recovery of valuable metals from spent lithium-ion batteries using deep eutectic solvents (DESs) is an environmentally and economically beneficial process. In this study, a method has been developed for recovering LiNi0.33Co0.33Mn0.33O2. Our process operates under mild conditions and with a little oxalic acid as a reducing agent, dissolving lithium, cobalt, manganese, and nickel completely utilizing a DES that is composed of tetrabutylammonium chloride and of monochloroacetic acid. Lithium and nickel were selectively precipitated using oxalic acid. Cobalt and manganese were precipitated as oxalates by adding an oxalic acid aqueous solution. Finally, the DES can be regenerated by evaporating the water. Importantly, valuable metals can be recovered with a 100 % yield through the process of DES recycling. This environmentally friendly and recyclable process is suitable for the recycling of spent lithium-ion batteries industry.

Intermetallic Ni3Ga1 Catalyst for Efficient Ammonia Reforming of Light Alkane.

Ammonia reforming of light alkane is conventionally employed for HCN production where coproduct H2 is burned for heating owing to the high reaction temperature (1200 °C) of such a highly endothermic process. Here, we show that a Ni3Ga1 intermetallic compound (IMC) catalyst is highly efficient for such a reaction, realizing efficient conversion of C1-C3 alkanes at 575-750 °C. This makes it feasible for on-purpose COx-free H2 production assuming that ammonia, as an H2 carrier, is ubiquitously available from renewable energy. At 650 °C and an alkane/ammonia ratio of 1/2, ethane and propane conversion of ∼20% and methane conversion of 13% were obtained (with nearly 100% HCN selectivity for methane and ethane) over the unsupported Ni3Ga1 IMC, which also shows high stability due to the absence of coke deposition. This breakthrough is achieved by employing a stoichiometric Ni3Ga1 mixed oxalate solid solution as the precursor for the Ni3Ga1 IMC.

Effect of Anodizing Voltage and Tobacco Extract Addition on the Structure of Porous Anodic Aluminum Oxide (PAAO) Layer

Porous Anodic Aluminum oxide (PAAO) is a porous oxide layer resulting from anodization. The structure of PAAO is influenced by anodization parameters, i.e., voltage and electrolyte composition. Increasing anodization voltage can affect the process of pore formation and oxide growth during anodization. Adding additives such as ethanol, propanol, and polyethylene glycol (PEG) can increase pore regularity and affect the structure of PAAO. In this study, tobacco extract (TE) was added to the oxalic acid-based anodizing solution. TE has many active compounds that may affect pore formation and oxide growth. Morphological analysis shows decreased pore diameter when adding tobacco extracts with concentrations of 0, 0.1, and 0.5 g/L, namely 43.92, 41.42, and 37.8 nm at anodization voltage 40 V. In anodization with a voltage of 60 V, a decrease in pore diameter was obtained with 46.47, 34.24, and 26.8 nm for adding tobacco extract 0, 0.1, and 0.5 g/L. The thickness of PAAO increases from 6.45 µm to 16.87 µm with increasing anodization voltage and tobacco extract concentration. The increase of tobacco extract concentration can lead to the decrease of the XRD peak intensity, where the sequence of the most significant decrease was observed for the peaks of (111), (220), (200), and (311), respectively. A decrease in the intensity ratio of (111) and (220) AAO peaks indicates the influence of tobacco extract on the anodization process. Further thermal analysis by Thermo-gravimetric (TG) shows an increase in mass loss from 1.47 to 5.37% with increasing tobacco extract concentration from 0 g/L to 0.5 g/L. TG results indicate the incorporation of tobacco extract in the inner pore wall.

Determination of the Maillard reaction products in complementary rice, flour, and noodles by high performance liquid chromatography with a diode array detector

AbstractA method was established for the simultaneous determination of furosine, furanone, and four furfural compounds (5‐hydroxymethylfurfural, furfural, furyl methyl ketone, and methyl furfural) in complementary rice, flour, and noodles for infants and young children by high performance liquid chromatography with a diode array detector. The sample was extracted using oxalic acid aqueous solution as a solvent, and the protein was removed using trichloroacetic acid. Then the six Maillard reaction products were separated by an Eclipse XDB‐C18 column with a gradient elution at a flow rate of 0.6 mL/min using acetonitrile‐0.1% trifluoroacetic acid solution as the mobile phase, detected by a diode array detector and quantified by external standard method. The linear ranges of the six Maillard reaction products were 250–20000 μg/100 g with the correlation coefficients greater than 0.999, and the limits of quantification ranged from 250 to 1000 μg/100 g (S/N ≥ 10). The recoveries of the six Maillard reaction products ranged from 71.2% to 100% with a relative standard deviation of 0.9%–4.9%. The real sample analysis results showed that 5‐hydroxymethylfurfural was detected in two cookie samples, the contents of which were 335 μg/100 g and 436 μg/100 g, respectively. There are no studies on the detection of the six Maillard reaction products in rice, flour, and noodles in the previous reports. The established method provided reference for the quantification of expiration date in complementary rice, flour, and noodles for infants and young children.