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A base-free catalytic system for the aerobic oxidation of 5-hydroxymethyl-2-furfural was exploited by using Pt nanoparticles immobilized onto a thermoresponsive poly(acrylamide-co-acrylonitrile)-b-poly(N-vinylimidazole) block copolymer, with an upper critical solution temperature of about 45 °C. The Pt nanocatalysts were well-dispersed and highly active for the base-free oxidation of 5-hydroxymethyl-2-furfural by molecular oxygen in water, affording high yields of 2,5-furandicarboxylic acid (up to >99.9%). The imidazole groups in the block copolymer were conducive to the improvement of catalytic performance. Moreover, the catalysts could be easily separated and recovered based on their thermosensitivity by cooling the reaction system below the upper critical solution temperature. Good stability and reusability were observed over these copolymer-immobilized catalysts with no obvious decrease in catalytic activity in the five consecutive cycles.

Background: The influence of the potassium metal cation on the graphitic carbon nitride (g-C3N4) photocatalyst has been studied in the partial oxidation of 5-hydroxymethyl-2-furfural (HMF) to 2,5-furandicarboxaldehyde (FDC). Objective: The aim of this study was to understand if the presence of K in C3N4 could increase the oxidative conversion of HMF to high added value species. Methods: Two sets of photocatalysts were prepared by following two different methodologies. In both series of the materials, the precursor of C3N4 was melamine with different types of the K containing species including KCl and KOH in one case and KNO3 alone in the other case. However, for both series of photocatalysts, materials were prepared with different amounts of potassium. Results: The results obtained by using materials prepared by the two different methodologies indicate that in both cases the presence of K was almost irrelevant at least for the lower amounts of potassium content. On the contrary, its presence was beneficial for the activity versus the photocatalytic partial oxidation reaction of the alcohol for the highest K content. Conclusion: Some of the prepared K containing g-C3N4 materials showed increased photocatalytic activity for the partial oxidation reaction of HMF in water, particularly by using natural solar light as the irradiation source.

The study estimated changes of 5‐hydroxymethyl‐2‐furfuraldehyde (5‐HMF) in different ginseng products with different temperatures and time pretreatment. Heat treatment was performed at various temperatures for 1.50, 2.00, 2.50, and 3.00 hr, respectively. Ultrasonic extraction and reflux extraction were used to evaluate the extraction rate and different solvents (such as 80% methanol, dichloromethane, ethyl acetate, and an extraction with both dichloromethane and ethyl acetate solvents) using two extraction methods (liquid–liquid extraction and solid‐phase extraction) to remove matrix interference. An ultraperformance liquid chromatography–mass spectrometer (UPLC‐MS) method was used for quantitative and changing analysis of 5‐HMF in different ginseng samples. The results indicated that the content of 5‐HMF increased dramatically with heating temperature and time, and the 5‐HMF in the ginseng samples ranged from 0.01 to 112.32 g/kg protein. The highest value was observed in the honey‐added ginseng samples with the highest amount of addition and highest temperature treatment, and the lowest value was found in the fresh ginseng samples. These results implied that 5‐HMF may be as an indicator to estimate the honey addition level and heat treatment degree during the processing of ginseng products, and the content of 5‐HMF is a promising parameter to evaluate the quality of products (ginseng). The production and regulation of potentially harmful Maillard reaction products (PHMRPs)‐5‐HMF in ginseng manufacture will provide an important reference for safe ginseng processing., The identification of 5‐hydroxymethyl‐2‐furfural (5‐HMF) in ginsengs was confirmed using an ultraperformance liquid chromatography–mass spectrometer (UPLC‐MS) method. The generation and regulation of potentially harmful Maillard reaction products (MRPs) 5‐HMF in ginseng processing are investigated and made suggestions for considering 5‐HMF as an evaluating indicator for quality of ginseng products.

Made available in DSpace on 2021-06-25T10:50:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 SiO2-SO3H, with a surface area of 115 m2/g, pore volumes of 0.38 cm3g−1 and 1.32 mmol H+/g, was used as a 10% w/w catalyst for the preparation of 5-hydroxymethyl-2-furfural (HMF) from fructose. A conversion of 100% was achieved in a microwave reactor during 10 min at 150 °C in DMSO, with 100% selectivity for HMF, at a molar ratio of fructose: DMSO equal to 1:56. The catalyst could be re-used three times. Department of Pharmacy Universidade Federal dos Vales do Jequitinhonha e Mucuri-UFVJM, Campus JK, Rodovia MGT 367 - Km 583, nº 5.000, Alto da Jacuba Department of General and Inorganic Chemistry Institute of Chemistry São Paulo State University-Unesp, R. Prof. Francisco Degni 55, Quitandinha Department of Physics and Chemistry Faculdade de Ciências Farmacêuticas de Ribeirão Preto São Paulo University-USP, Av. do Café s/n Faculdade de Ciências Farmacêuticas Alimentos e Nutrição Universidade Federal do Mato Grosso do Sul - UFMS, Av. Costa e Silva, s.n. Centro universitário SENAI-CIMATEC, Av. Orlando Gomes, 1845, Piatã Department of General and Inorganic Chemistry Institute of Chemistry São Paulo State University-Unesp, R. Prof. Francisco Degni 55, Quitandinha

A series of gold catalysts supported on pure CeO2, ZrO2, and two different Ce-Zr mixed oxides have been prepared and tested in the 5-hydroxymethyl-2-furfural oxidation reaction. All catalysts show high catalytic activity (100% conversion) and important selectivity (27–41%) to the desired product i.e., 2,5-furandicarboxylic acid at low base concentration. Products selectivity changes with the support nature as expected, however, the observed trend cannot be related neither to gold particle size, nor to catalyst reducibility and oxygen mobility. An important relation between the FDCA selectivity and the support textural properties is observed, conducing to the general requirement for optimal pore size for this reaction. Ministerio de Economía y Competitividad ENE2017-82451-C3-3-R

Efficient catalytic aerial oxidation of biomass-derived 5-hydroxymethyl-2-furfural (5-HMF) to the industrially important furan-2,5-dicarboxylic acid (FDCA) was achieved over bimetallic M0.90–Pd0.10 (M = Ni, Co or Cu) alloy nanoparticles supported on in situ prepared Mg(OH)2 nanoflakes. In comparison to Co- and Cu-based bimetallic nanoparticles, Ni0.90Pd0.10/Mg(OH)2 exhibited superior catalytic performance. Catalytic reactions performed using Ni1−xPdx/Mg(OH)2 (x = 0.10 to 1) and a physical mixture of Ni/Mg(OH)2 and Pd/Mg(OH)2 revealed that the significant synergistic cooperation between Ni and Pd plays a crucial role in the observed high catalytic activity of Ni0.90Pd0.10/Mg(OH)2 for the oxidation of 5-HMF to FDCA. Experiments performed with Ni0.90Pd0.10 on different supports (SiO2, Al2O3, ZnO and Mg(OH)2) revealed that the basicity of the support is advantageous for efficient oxidation of 5-HMF, and it avoids the use of an external base additive. Moreover, the Ni0.90Pd0.10/Mg(OH)2 catalytic system can be scaled to gram-level oxidation of 5-HMF to FDCA. Subsequently, the synthesized FDCA was employed for the synthesis of various furan diesters (bis(2-hydroxyethyl), dimethyl, diethyl, dipropyl and dibutyl furan-2,5-dicarboxylate) as precursors for biomass-derived plastics. Moreover, structural and chemical identification of the highly active Ni0.90Pd0.10/Mg(OH)2 was established by P-XRD, SEM, TEM, EDS, elemental mapping and ICP-AES analysis.

Single-crystalline Pd nanocrystals enclosed by {111} or {100} facets with controllable sizes were synthesized and originally employed as catalysts in the aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF). The experimental results indicated that the particle size and exposed facet of Pd nanocrystals could obviously influence their catalytic performance. The size-dependent effect of Pd nanocrystals in this reaction could only be derived from the different Pd dispersions. Therefore, the facet effect of Pd nanocrystals was first investigated in this work through experimental and theoretical approaches. It was found that Pd-NOs enclosed by {111} facets were more efficient than Pd-NCs enclosed by {100} facets for the aerobic oxidation of HMF, especially for the oxidation step from 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) toward 5-formyl-2-furancarboxylic acid (FFCA). The TOF value of Pd-NOs(6 nm) was 2.6 times as high as that of Pd-NCs(7 nm) and 5.2 times higher than that of commercial Pd/C catalyst f...

This work was supported by Natural Science Foundation of Tianjin (Grant No. 17JCYBJC22600) and the Fundamental Research Funds for the Central Universities. The aerobic oxidation of alcohols and aldehydes over noble metal catalysts is a critical reaction for the catalytic conversion of carbohydrates into value-added chemicals from biomass. However, to fully understand the reaction mechanism, in particular the role of O2 and the generated active oxygen species in these reactions is still a challenging target. In the present work, the sub-10 nm Pt nanocrystals with cubic (Pt-NCs), octahedral (Pt-NOs) and spherical (Pt-NSs) morphologies were synthesized and used as catalysts in aerobic oxidation of HMF. Through experimental and computational investigations, the facet-dependent O2 conversion pathway and catalytic oxidation performance were discussed. The molecular O2 tends to be dissoci-ated to generate •OH on Pt(100) surface, but prefers to be reduced to •O2- on Pt(111) surface. Moreover, Pt-NCs enclosed by the {100} facets exhibited significantly enhanced catalytic activity than Pt-NOs enclosed by the {111} facets and Pt-NSs, in particular for alcohol oxidation step. Based on the experimental data and density functional theory (DFT) calculations, an active oxygen species promoted dehydrogenation mechanism for aerobic oxidation of HMF was proposed. The dehydrogena-tion of alcohol group is more favourable on the Pt(100) surface with an assistance of •OH, which are the dominant active oxygen species on the Pt(100) surface. We anticipate that this work would provide a new insight into the role of active oxy-gen species in aerobic oxidation of alcohols and aldehydes over noble metal catalysts. Postprint

A series of CeZrO supports with different Ce/Zr molar ratios were utilized for the preparation of gold catalyst used in the selective oxidation of 5-hydroxymethyl-2-furfural to 2,5-furandicarboxylic acid. The used method of gold deposition allows the preparation of gold particles with homogeneous size and shape distribution, a formulation very useful for studies dedicated to revealing the support participation in the reaction. The supports are characterized by Fourier transform infrared spectroscopy using CO as probe molecule, and the sample catalytic activity is thereafter correlated to the support acid site distribution. The possible participation of its Lewis/Brønsted acidity in the reaction mechanism is also proposed., K.C. acknowledges the financial support from the National Science Fund of Bulgaria (Contract No. DN 19/2).

In this work an HPLC-DAD determination method for free and total HMF in “dulce de leche” was developed and validated. The separation was carried out using a mobile phase of acetonitrile-water (4.5:95.5, v/v) on Acclaim™120 C18 (4.6 × 150 mm, 5 μm), at 30 °C and a flow rate of 1 mL/min. The detection was done at 284 nm.The method showed good selectivity and linearity (determination coefficient over 0.999). Low LOD and LOQ values were obtained (19.51 μg/L and 65.05 μg/L respectively). Relative standard deviation (RSD) for repeatability and intermediate precision was

An environmentally benign and homogeneous base-free route for 5-hydroxymethyl-2-furfural (HMF) aerobic oxidation to 2,5-furandicarboxylic acid (FDCA) in water was reported using Mg–Al–CO3 hydrotalcite-supported Pd nanoparticles (xPd/HT-n) as catalyst. The influences of the Mg/Al molar ratio of hydrotalcite and Pd loading amount on the catalytic performance of these catalysts were originally systematically investigated. These catalysts exhibited excellent catalytic activity and FDCA selectivity in the HMF oxidation, especially for 2%Pd/HT-5 and 2%Pd/HT-6; >99.9% FDCA yields were achieved for 8 h under ambient pressure and homogeneous base-free conditions. The remarkably improved catalytic performance could be attributed to the suitable basicity of the Mg–Al–CO3 hydrotalcite and the abundant OH– groups on the surface of hydrotalcite. The plausible reaction mechanism was proposed based on the results of a series of controlled experiments. Furthermore, these catalysts were quite stable and could be reused at ...

In this work the development and in house validation of the HMF direct determination in corn and cane syrups by HPLC-UV was carried out for the first time. The separation was done with isocratic elution of a mobile phase comprising water (with 0.5% formic acid) and acetonitrile (90:10, v/v) on Phenomenex C18 column (5.0 μm, 4.6 × 150 mm), at 30 °C, flow rate of 0.8 mL min(-1) and detection at 285 nm. The validated method showed excellent performance with low limits (LOD and LOQ of 0.09 and 0.26 mg L(-1), respectively), good accuracy (recovery rates between 100% and 104%) and precision (RSD's for repeatability and intermediate precision between 0.57% and 6.43%). Good selectivity and linearity were also observed. HMF contents in both foods were very high (406.6-2121.3 mg kg(-1) for corn syrup and 109.2-893.1 mg kg(-1) for cane syrup), which arouses concern about food safety of these products.

Heterogeneous selective oxidation of 5-hydroxymethyl-2-furfural (HMF) into 2,5-diformylfuran (DFF) using molecular oxygen and vanadium catalyst onto activated carbon in MIBK, extracting solvent for HMF, is described. Highly stable V2O5 supported on activated carbon catalyst was synthesized using V3 + (VCl3) precursor and confirmed by XPS analysis, which found to be highly active. A maximum HMF conversion of > 95% with > 96% DFF selectivity was achieved and this heterogeneous catalyst could be used 4 times without any significant loss of activity.

Supercritical carbon dioxide fluid extraction was used to extract 5-hydroxymethyl-2-furfural from caramel colour (solid content was about 75%). The procedure was carried out by response surface methodology using a quadratic polynomial model. Extraction pressure, time, temperature and ethanol content were selected as the independent variables. Conditions to obtain the highest extraction ratio of 5-hydroxymethyl-2-furfural were determined to be an extraction pressure of 21.65 MPa, time of 46.7 min, temperature of 35 °C and 70% ethanol content of caramel colour. The predicted 5-hydroxymethyl-2-furfural extraction ratio was 87.42%. Under the conditions stated above, the experimental value of 5-hydroxymethyl-2-furfural extraction ratio was 86.98%, which was similar to the predicted value by the model. This study indicated that supercritical carbon dioxide fluid extraction can effectively reduce 5-hydroxymethyl-2-furfural from caramel colour, which can help food industry to improve the safety of the food material, as well as provide more healthy caramel colour for human beings.

The chemical structure of 5-hydroxymethyl-2-furfural (HMF), its physicochemical properties and reactions that lead to the synthesis of HMF were discussed. Special attention was paid to HMF formation in food during processing. The potential applications of this compound in industry were described as well. Moreover, this review outlines the most important sources of HMF in human diet and estimates the potential daily intake of HMF by consumers. The known and suggested metabolic pathways, as well as the impact of HMF and its metabolites on human health are also discussed.

In this study, an ultra-high-performance liquid chromatography method was developed to detection the levels of 5-hydroxymethyl-2-furfural (HMF) in 227 selected food products obtained from the Chinese markets. The performance of the analysis method was evaluated by some quality parameters such as limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, and run-to-run (n = 6) and day-to-day (n = 18) precisions. The LOD and the LOQ of the method in different food matrices ranged from 0.15 to 0.50 and from 0.35 to 1.20 mg kg−1, respectively. The results from this study showed that HMF was mostly detected in all samples selected. HMF contents in different samples varied greatly according to the raw materials and processing conditions. The highest level of HMF was found in preserved fruits and ground coffee, with average levels of 409.6 and 409.9 mg kg−1, respectively. Preliminary estimates of HMF exposure from foods in the Chinese population was estimated to be 0.12 mg kg−1 body weight day−1, which is relatively low compared with the result reported by JECFA and European Food Safety Authority.

Homogenous bis-sulfonic acid ionic liquids (1 mol equiv.) in DMSO (10 mol equiv.) at 100 °C efficiently mediated the conversion of D-fructose into 5-hydroxymethyl-2-furfural in 75% isolated yield, which was roughly a 10% increment compared to the case of the mono-sulfonic acid ionic liquids.

This study aimed to investigate the mechanism of acrylamide formation during heating asparagine (ASN) at elevated temperatures with glucose (GLC), and 5-hydroxymethyl-2-furfural (HMF). The results revealed that HMF rapidly reacted with ASN, leading to acrylamide formation. The ASN-HMF model system generated acrylamide more efficiently than the ASN-GLC model system during heating at 180°C. A significantly higher amount of 3-aminopropionamide (3-APA) was formed in the ASN-HMF model system than in the ASN-GLC model system within 5min at 180°C. The amount of 3-APA decreased after 5min of heating in both model systems while the amount of acrylamide continued to increase in the ASN-HMF model system. In-depth high resolution mass spectrometry analyses of reaction products formed in the model systems together with the kinetic data suggested that HMF is a potent carbonyl accelerating acrylamide formation during heating. 3-APA was found as one of the key intermediates leading to acrylamide formation.

5-Hydroxymethyl-2-furfural (5-HMF) is considered to be an excellent indicator of quality deterioration due to excessive heating or storage for a wide range of carbohydrate-containing foods. To facilitate its analysis, a highly selective and sensitive enzyme-linked immunosorbent assay for determination of 5-HMF in food has been developed. A specific polyclonal antibody was produced against a conjugate of 5-HMF coupled to bovine serum albumin. The IC(50) and limit of method detection were 0.15 ± 0.012 mg L(-1) and 0.02 ± 0.002 mg L(-1), respectively. The proposed method was applied to detect 5-HMF in French mini bread, potato chips, French soft bread, and wheat chicken nuggets with recoveries ranging from 84.07 to 97.09% and relative standard deviation (n = 3) below 8.65% in all samples. The quantitative results were in good agreement with those obtained by the high-performance liquid chromatography method, which suggests that the method developed will be very useful for monitoring 5-HMF in food samples.

This study describes a method for the determination of 5-hydroxymethyl-2-furfural (HMF) and 2-furfural (F) in oils. The method entails liquid–liquid extraction and reversed-phase liquid chromatography. Spiked hazelnut oil was used to test the accuracy and reliability of the method. Furan compounds were extracted from oil using 70% methanol. Mean recoveries were 97 ± 2% and 99 ± 1% for HMF and F, respectively. To investigate the presence of HMF and F in oils, seven oily nuts and seeds were roasted at 180 °C for 30 min. Different oils were found to contain HMF and F ranging from 0.8 to 13.8 and 1.4 to 8.7 mg/kg, respectively. Increasing solvent polarity also increased the rate of HMF transferred to the oil. Spectral analyses of the 70% methanol extracts indicated that absorbance at 285 nm may be used to monitor the accumulation of furan compounds in oil phase during the roasting process of nuts.

α-Dicarbonyl compounds, namely glyoxal (GO), methylglyoxal (MGO) and 3-deoxyglucosone (3-DOG), as well as 5-(hydroxymethyl)-2-furfural (5-HMF) were found and measured in carbonated soft drinks (CSD). It was realized that high fructose corn syrup (HFCS) in regular CSDs was the major source of α-dicarbonyl compounds in beverages after comparison of levels in regular and diet CSDs. In two most commonly used HFCS formulas, 42% and 55% HFCS, the highest level of dicarbonyl found was 3-DOG, followed by MGO, and then GO. The stability of dicarbonyls in CSDs containing HFCS and (-)-epigallocatechin gallate (EGCG) which were incubated at 35 and 45 °C was investigated. It was found that EGCG decreased from 1 mg/mL to 0.5 and 0.3 mg/mL for 35 and 45 °C, respectively, in 16 days storage. Moreover, the reactions of EGCG with MGO, 3-DOG and 5-HMF were observed from the comparison of storage CSDs with and without EGCG under acidic conditions.

A new method for the synthesis of 5,5′-oxydimethylenebis (2-furfural) by thermal dehydration of 5-hydroxymethyl-2-furfural in the presence of dimethyl-sulfoxide is described. Optimum conditions are studied by experimental design. Reaction media present a high concentration of HMF. Reaction is supposed to be rapid. Yields reach 55% with a 84% selectivity.

The formation of 5-hydroxymethyl-2-furfural (HMF) and 5-hydroxymethyl-2-furoic acid (HMFA) during roasting of coffee was studied. At 240 degrees C the maximum concentration of HMF occurs after 3 min with a quick degradation up to 10 min when most of the HMF has disappeared again. Similar to 5-hydroxymethyl-furfural, HMFA is formed in coffee but not in a model system consisting of sucrose, alanine with or without chlorogenic acid. It was shown that HMFA is produced from different precursors than HMF namely glyceraldehyde and pyruvate. The comparison of the laboratory scale roasting with industrial roasting showed that 5-hydroxymethyl-furfural decreases with a higher degree of roasting whereas HMFA did not change. In the laboratory scale experiments, the highest concentration of 5-hydroxymethyl-furfural in coffee (909 microg/g) was obtained after 3 min and the maximum concentration of HMFA after 4 min (150 microg/g). Industrially roasted coffee contained up to 350 microg/g 5-hydroxymethyl-furfural and 140 microg/g HMFA.

バイオマスやセルロースの熱分解によって得られるヒドロキシメチルフルフラール (HMF) を原料としてポリエステルの合成を行った. HMFを還元して得られるビスヒドロキシメチルフラン (BHF) を天然のジカルボン酸であるコハク酸, フマル酸, マレイン酸と重縮合を行ってポリエステルを合成した. 重縮合は, 酸クロリドを用いる方法と縮合剤を用いる方法により行った. 縮合剤を用いて合成したBHFとコハク酸とのポリエステルの数平均重合度は最高30のものが得られ, NMRおよびIRスペクトルから直鎖状の規則性ポリマーであることがわかった. また, 2種類のジカルボン酸を混合してBHFと重縮合を行って, 共重合体を合成した. 得られたポリエステルのDSC測定から, ポリエステルの融点とガラス転移点を求めた.

The inhibition of mushroom tyrosinase by methanolic extract of Dictyophora indusiata was evaluated and the bioactive component was characterized and identified as 5-(hydroxymethyl)-2-furfural (HMF) by chromatographic and spectroscopic means. Kinetic studies revealed it to be a noncompetitive inhibitor for the oxidation of L-DOPA. On the basis of these findings some related analogues were also tested for their anti-tyrosinase activity, in order to gain more insight into structure and activity relationship among these heterocyclic compounds.

5-Hydroxymethyl-2-furfural (2a) was formed in a 70% yield by dehydration of glucose in MeCN at 140 °C in an autoclave using a composite of MgCl2 with silica gel which served as an acid catalyst und...

A novel 5-hydroxymethyl-2-furfural (HMF; 1) derivative, which is named asfural (compound 2), was isolated from enzyme-treated asparagus extract (ETAS) along with HMF (1) as a heat shock protein 70 (HSP70) inducible compound. The structure of compound 2 was elucidated on the basis of its spectroscopic data from HREIMS and NMR, whereas the absolute configuration was determined using chiral HPLC analysis, compared to two synthesized compounds, (S)- and (R)-asfural. As a result, compound 2 derived from ETAS was assigned as (S)-(2-formylfuran-5-yl)methyl 5-oxopyrrolidine-2-carboxylate. When compound 2, synthesized (S)- and (R)-asfural, and HMF (1) were evaluated in terms of HSP70 mRNA expression-enhancing activity in HL-60 cells, compound 2 and (S)-asfural significantly increased the expression level in a concentration-dependent manner. HMF (1) also showed significant activity at 0.25 mg/mL.

In this study, a method for rapid detection of 5-hydroxymethyl-2-furfural (HMF) was investigated. Monoclonal antibody (anti-HMF) was prepared and evaluated by an indirect competitive ELISA (ic-ELISA) format. The optimized standard curve was y=-0.2097x+1.0432 [where x is the logarithm (base 10) of the values of the HMF concentration and y is the absorbance of ic-ELISA results tested at 490 nm] and the linear detection range was 0.008 to 32.768 mg/L. The percentage of cross-reactivity of HMF with 5 major furfural derivatives was less than 2.92%. Finally, the established ic-ELISA format was used to test HMF in milk, and compared with the result obtained by HPLC, which produced an error of about 0.3%. Based on the data in this experiment, we concluded that the established ic-ELISA format was reliable with a high specificity.

5-Hydroxymethyl-2-furfural (2a) was formed in a 70% yield by dehydration of glucose in MeCN at 140 °C in an autoclave using a composite of MgCl2 with silica gel which served as an acid catalyst und...

The aim of this study was to elucidate the structure of a potential ageing marker for Cava sparkling wine. In order to clarify the structure of this compound, NMR spectroscopy and hyphenated UHPLC-DAD-MS/MS techniques were used. We identified the hitherto unknown compound as 5-hydroxymethyl-2-furfuraldehyde (5-HMF). This is the first time that this compound has been reported in sparkling wines. A survey, based on the analysis of 80 commercial sparkling wines, showed that 5-HMF is present between 0.25 and 12.81 mg/L, and is compared with those reported for other types of wine. Hypothetical origin of 5-HMF in Cava sparkling wine is discussed.

All lanthanide(III) ions were found to catalyze dehydration of saccharides to 5-hydroxymethyl-2-furfural (HMF) in DMSO at 100 - 120 °C. Particularly, D-fructose was almost quantitatively converted to HMF without generating any byproducts. The results of the reaction with di- and trisaccharides indicated that the D-fructose moiety in the substrates was selectively converted to HMF.

(1995). ULTRASONICALLY ACCELERATED SYNTHESES OF FURAN-24-DICARBALDEHYDE FROM 5-HYDROXYMETHYL-2-FURFURAL. Organic Preparations and Procedures International: Vol. 27, No. 5, pp. 564-566.

All lanthanide(III) ions were found to catalyze dehydration of saccharides to 5-hydroxymethyl-2-furfural (HMF) in DMSO at 100 - 120 °C. Particularly, D-fructose was almost quantitatively converted to HMF without generating any byproducts. The results of the reaction with di- and trisaccharides indicated that the D-fructose moiety in the substrates was selectively converted to HMF.

General toxicity (A) and vein damaging properties (B) of 5-hydroxymethyl-2-furfural (HMF) were studied in rabbits. A. 400 mg HMF was given as subcutaneous injections twice a day for a week. It was not possible to demonstrate any harmful effect of the injecitions on the following parameters: weight, haemoglobin, leucocytes, platelets, serum-protein, serum-alanine-aminotransferase, alkaline phosphatase, liver cell necrosis or hepatic steatosis as compared with a control group. B. Addition of 200 mg HMF/l isotonic NaCl solution did not increase the vein irritating effect of the solution, when given as a 5 hours' continuous intravenous infusion. The amounts of HMF used in this study far exceeded what patients receive from glucose solutions.

The proposed method includes analysis of the serum obtained after suitable sample dilution and Carrez addition followed by 12 000 rpm centrifuging for 2 h by HPLC, using a reverse-phase C18 column and an ultraviolet detector operating at 285 nm in isocratic elution with 90:10 water-methanol. Juice and paste (double and triple) samples have been analysed by means of two methods (Winkler and HPLC) and statistical analysis, carried out on the results, clearly shows a difference between them. In particular, the colorimetric method which includes no centrifuging, but only filtration, almost always yields results which are lower than the HPLC ones.