Carcinogenic Formaldehyde Research Articles

How do different marine engine fuels and wet scrubbing affect gaseous air pollutants and ozone formation potential from ship emissions?

Sulphur Emission Control Areas (SECAs), mandated by the International Maritime Organization (IMO), regulate fuel sulphur content (FSC) to mitigate the environmental and health impact of shipping emissions in coastal areas. Currently, FSC is limited to 0.1% (w/w) within and 0.5% (w/w) outside SECAs, with exceptions for ships employing wet sulphur scrubbers. These scrubbers enable vessels using non-compliant fuels such as high-sulphur heavy fuel oils (HFOs) to enter SECAs. However, while sulphur reduction via scrubbers is effective, their efficiency in capturing other potentially harmful gases remains uncertain. Moreover, emerging compliant fuels like highly aromatic fuels or low-sulphur blends lack characterisation and may pose risks.Over three years, we assessed emissions from an experimental marine engine at 25% and 75% load, representative of manoeuvring and cruising, respectively. First, characterizing emissions from five different compliant and non-compliant fuels (marine gas oil MGO, hydro-treated vegetable oil HVO, high-, low- and ultra-low sulphur HFOs), we calculated emission factors (EF). Then, the wet scrubber gas-phase capture efficiency was measured using compliant and non-compliant HFOs.NOx EF varied among fuels (5200–19700 mg/kWh), with limited scrubber reduction. CO (EF 750–13700 mg/kWh) and hydrocarbons (HC; EF 122–1851 mg/kWh) showed also insufficient abatement. Carcinogenic benzene was notably higher at 25% load and about an order of magnitude higher with HFOs compared to MGO and HVO, with no observed scrubber reduction. In contrast, carbonyls such as carcinogenic formaldehyde and acetaldehyde, acting as ozone precursors, were effectively scrubbed due to their polarity and water solubility. The ozone formation potential (OFP) of all fuels was examined.Significant EF differences between fuels and engine loads were observed, with the wet scrubber providing limited or no reduction of gaseous emissions. We suggest enhanced regulations and emission abatements in the marine sector to mitigate gaseous pollutants harmful to human health and the environment.

Enhancing the valorization of pulping black liquors in production effective aerogel–carbon nanostructure as adsorbents toward cationic and ionic dyes

This work deals with promoting the efficiency of removing the cationic and ionic dyes by new aerogel–carbon nanostructures. For cleaner production the rice straw-pulping black liquors, which regards serious environmental risk during routine disposing, is used in preparing the aerogel precursors. These aerogels (AGBs) depend on using pulping black liquor in hybrid with resorcinol and the less carcinogenic formaldehyde butyraldehyde. Black liquors from five pulping processes are used, Elemental, thermogravimetric (TGA and DTG), and FTIR-ATR analyses are used to characterize the carbon precursors. While their adsorption behavior toward cationic and anionic dyes are accessed via iodine-value, adsorption capacity and kinetic models, textural characterization, and SEM. The TGA measurements reveal that AGBs from BLs of neutral sulfite and soda-borohydride pulping reagents have higher activation and degradation energies than other aerogels. In terms of cationic and anionic dyes adsorption as well as textural characterization, the AGB-CNSs surpass that made from BLs. The discarded KOH/NH4OH black liquor is used to synthesize the best aerogel precursor for producing cationic methylene blue dye (MB) adsorbent, where it provides an adsorption capacity 242.1 mg/g. The maximum anionic brilliant blue dye (BB) adsorption capacity, 162.6 mg/g, is noticed by Kraft BL-aerogel-CNSs. These finding data overcome the literature carbon adsorbents based on lignin precursors. All examined CNSs toward MB dye follow the Langmuir adsorption equilibrium; while primarily the Freundlich model for BB dye. The pseudo-second-order kinetic model well fits the adsorption kinetics of investigated AGB-CNSs. The textural characterization and SEM revealed a mixture of mesoporous and micro porous features in the CNSs.

Self-heating photothermal synergistic catalytic decomposition of carcinogenic formaldehyde by α-MnO2 at ambient temperature: Functional roles of surface acidic-basic sites

Formaldehyde is a major pollutant in indoor atmosphere, and the realization of complete mineralization of formaldehyde at room temperature is of great significance and practical demand for improving indoor air quality. Surface acidic-basic sites, as one of the important surface properties that have significant influence on catalytic oxidation of formaldehyde, revealing their functions is beneficial for the development of efficient formaldehyde decomposition materials. Herein, the α-MnO2 acidic-basic sites were regulated and its effects on self-heating photothermal catalytic oxidation of formaldehyde were further contrastive investigated. The acidic-basic sites showed distinct functions: the basic sites exhibited a significant promotion on formaldehyde oxidation; While the acidic sites greatly inhibited the reactivity. Particularly, the basicity enhanced α-MnO2 could reach the 100% conversion of formaldehyde at ambient temperature. Furthermore, the self-heating photothermal mechanism was consonant with the thermal-assisted photocatalysis mechanism, rather than traditional photo-drive thermal catalysis mechanism. The strength of basic sites significantly increased the content of surface hydroxyl groups, and the electron-rich basic sites were favorable for the activation of oxygen, thereby generating more reactive oxygen species for the decomposition of formaldehyde. Moreover, in-situ DRIFTS reveals that the enhancement of basic sites can accelerate the rate oxidation of HCHO to generate formates and carbonates. This work clarified the influence of surface acid-base properties on formaldehyde photothermal decomposition.

Carcinogenic formaldehyde in U.S. residential buildings: Mass inventories, human health impacts, and associated healthcare costs

Formaldehyde, a human carcinogen, is formulated into building materials in the U.S. and worldwide. We used literature information and mass balances to obtain order-of-magnitude estimates of formaldehyde inventories in U.S. residential buildings as well as associated exposures, excess morbidity, and healthcare costs along with other economic ramifications. Use of formaldehyde in building materials dates to the 1940s and continues today unabated, despite its international classification in 2004 as a human carcinogen. Global production of formaldehyde was about 32 million metric tons (MMT) in 2006. In the U.S., 5.7 ± 0.05 to 7.4 ± 0.125 MMT of formaldehyde were produced annually from 2006 to 2022, with 65 ± 5 % of this mass (3.7 ± 0.03 to 4.8 ± 0.08 MMT) entering building materials. For a typical U.S. residential building constructed in 2022, we determined an average total mass of formaldehyde containing chemicals of 48.2 ± 10.1 kg, equivalent to 207 ± 40 g of neat formaldehyde per housing unit. When extrapolated to the entire U.S. housing stock, this equates to 29,800 ± 5760 metric tons of neat formaldehyde. If the health threshold in indoor air of 0.1 mg/m3 is never surpassed in a residential building, safe venting of embedded formaldehyde would take years. Using reported indoor air exceedances, up to 645 ± 33 excess cancer cases may occur U.S. nationwide annually generating up to US$65 M in cancer treatment costs alone, not counting ~16,000 ± 1000 disability adjusted life-years. Other documents showed health effects of formaldehyde exist, but could not be quantified reliably, including sick building syndrome outcomes such as headache, asthma, and various respiratory illnesses. Opportunities to improve indoor air exposure assessments are discussed with special emphasis on monitoring of building wastewater. Safer alternatives to formaldehyde in building products exist and are recommended for future use.

A platinum ensemble catalyst for room-temperature removal of formaldehyde in the air

Minimal use of noble metals is ideal in developing catalytic systems against carcinogenic formaldehyde (FA) in air. Although single-atom catalysts (SACs) have been proposed to maximize atomic utilization, metals dispersed to the single-atom limit are less durable in redox environments. A highly dispersed platinum (Pt) ensemble (Ptn) on titanium dioxide (TiO2) was synthesized and validated to achieve 100% conversion of 100 ppm FA in dry air at room temperature (RT) at a gas hourly space velocity of 47,771 h−1. In contrast, Pt SAC (Pt1/TiO2) and a reference Pt nanoparticle catalyst (PtNP/TiO2) exhibited much lower performances. The turnover frequencies (TOFs) of Ptn/TiO2, Pt1/TiO2, and PtNP/TiO2 for the RT FA oxidation reaction were 0.03, 0.01, and 0.005 s−1, respectively. The critical role of the surface lattice oxygen (Olatt) in the overall reaction was supported by the prominence of the Mars van Krevelen kinetics in FA oxidation by the Ptn catalyst. The performance of the PtNP catalyst matched with Ptn only when the Pt loading in the former was raised to 2 wt%. Hence, the Pt dose can be reduced by one-fourth through the ensemble form dispersed at the sub-nanometer scale. The density functional theory simulation also distinguished the roles of different Pt catalysts. The Ptn sites could serve as an oxygen reservoir (effective dissociation of molecular oxygen) to promote proximate reactions (between the adsorbed –CHO and surface Olatt species). Conversely, Pt1 is a single site that restricts proximate reactions with vulnerability to surface poisoning.

ANALYSIS AND RECOMMENDATIONS ON THE USE OF POLYMER AND PHENOL-BASED MATERIALS FOR COAL MINES

In this study, besides summarizing the properties of polymer materials used in underground coal mines, the problems that may arise in the use of polymer materials used in coal mines and the deficiencies of the relevant existing standards are discussed. Most of the safety accidents of polymer materials are encountered with results such as spontaneous combustion of materials, combustion of coal seams due to these combustions, and the release of toxic and harmful gases. The main causes of combustion accidents can be summarized as high reaction temperature, insufficient flame retardant, uncontrollable reaction process, defective standards and awareness of insufficient safety materials. Within the scope of this study, health problems that may be encountered due to the carcinogenic formaldehyde content of phenol-based filling materials will also be mentioned, and reasonable suggestions and measures will be discussed to prevent these and similar situations. The aim and including of this study is to establish a guide on the safe use of polymer materials in underground coal mines and correct understanding of the possible risk associated.

A facile method for cross-linking of methacrylated wood fibers for engineered wood composites

Chemical modifications are widely used to enhance the properties of wood composites and create a strong bonding mechanism for enhancing the dimensional stability, water resistance as well as decreasing carcinogenic formaldehyde emission. Esterification is the most-known modification way to enhance the durability of wood composites, but it does not improve mechanical performance. In this work, we demonstrated a two-step, easy and quick wood surface modification strategy based on microwave heating and UV crosslinking. Firstly, the fiber surface was reacted with methacrylic anhydride, then using methacrylated groups on wood, the fibers are covalently linked. As a proof-of-concept the fibers cross-linked within five minutes under UV radiation using benzophenone solution. Then, the effect of crosslinked wood fiber on the properties of mechanical and swelling of fiberboard were studied. Using SEM, FTIR-ATR, and swelling tests, we investigated the wood-based products' reaction mechanism, morphology, and internal bonding strength. The chemical cross-linking gives stronger bonding, compared to hydrogen bonding, between fibers even in wet conditions, resulting in a cross-linked foam-like structure. Also, wood panels were fabricated, compared to unmodified fibers, the internal bond strength and dimensional stability of fiberboards increased slightly. Overall, these results show that chemical cross-linking of wood fibers can be a fast and promising way to produce multi-functional wood composites.

Organic compound and particle emissions of additive manufacturing with photopolymer resins and chemical outgassing of manufactured resin products

ABSTRACT Photopolymer resins are applied at an increasing rate in additive manufacturing (AM) industry as vat photopolymerization (VP) and material jetting (MJ) methods gain more popularity. The aim of this study was to measure volatile organic compound (VOC), carbonyl compound, ultrafine particle (UFP), and particulate matter (PM10) air concentrations emitted in 3D printer operations. Individual chemicals were identified when multiple photopolymer resin feedstocks were used in various VP and MJ printers. The size distributions of UFPs, and indoor air parameters were also monitored. Finally, the VOC outgassing of the cured resin materials was determined over 84 days. The data demonstrated that 3D printer operators were exposed to low concentrations of airborne exposure agents as follows: average concentrations of VOCs were between 41 and 87 µg/m3, UFP number levels ranged between 0.19 and 3.62 × 103 number/cm3; however, no impact was detected on air parameters or PM10 concentrations. A majority of the UFPs existed in the 10–45 nm size range. The identified compounds included hazardous species included sensitizing acrylates and carcinogenic formaldehyde. The outgassed products included similar compounds that were encountered during the AM processes, and post-processing solvents. Products heated to 37°C emitted 1.4‒2.9-fold more VOCs than at room temperature. Total emissions were reduced by 84‒96% after 28 days roughly from 3000–14000 to 100–1000 µg/m2/hr. In conclusion, resin printer operators are exposed to low concentrations of hazardous emissions, which might result in adverse health outcomes during prolonged exposure. Manufactured resin products are suggested to be stored for 4 weeks after their production to reduce potential consumer VOC hazards.

High-performance hard carbon anode prepared via an ingenious green-hydrothermal route

Phenolic resin, as a synthetic polymer precursor of hard carbon, has become the core anode precursor of sodium-ion batteries (SIBs). However, the carcinogenic formaldehyde is normally adopted in the synthesis of conventional phenolic resins. Meanwhile, the synthetic process is multifarious and prolonged, which is detrimental to mass production. In this paper, an eco-friendly phenolic resin was prepared by an efficient hydrothermal synthesis process using gentle and slightly toxic glyoxylic acid instead of notorious carcinogen formaldehyde. By adjusting the carbonization temperature of as-obtained phenolic precursor, the acquired optimal hard carbon anode material equipped a splendid reversible capacity of 325 mAh g−1 and a high initial coulombic efficiency (ICE) of 88.59%. Besides, it displayed an outstanding rate performance of 161.4 mAh g−1 for 300 cycles at 5 C with the capacity retention rate of 93.31%. When matched against the appropriate cathode, the full battery can provide a high energy density of 239 Wh kg−1, displaying excellent rate capability and cycling stability. The participation of “green” aldehyde monomer in hydrothermal synthesis process for acquiring phenolic resin is an efficient and scalable approach for obtaining higher energy storage anode, which can pave environmentally-friendly way for the realization of large-scale energy storage application.

Comparative Studies of Screen-Printed Electrode Based Electrochemical Biosensor with the Optical Biosensor for Formaldehyde Detection in Corn

In the present manuscript, we fabricated screen-printed electrode based biosensor and enzymatic optical biosensor for detection of carcinogenic formaldehyde. The biosensor strip using cyclic voltammetry technique exhibited high sensitivity of 352 μA mg−1 L cm−2 with detection limit of 0.03 mg/L, and sensitivity of 0.186 Abs (mg/L)−1 with detection limit of 0.02 mg/L was obtained with optical biosensor over the concentration range of 0.01–0.5 mg/L. This electrochemical sensing result was compared with that of enzymatic optical sensing obtained with α-Fe2O3/ITO bioelectrode on the same sample, under similar environmental conditions, obtaining a high correlation (r2 = 0.988). The non-availability of biosensor for formaldehyde detection in corn as a food and feed stimulated our research efforts in this direction. The results of the study may have implications in developing a range of biosensors for the quantification of adulterants and contaminants along the whole food supply chain from farm to fork.

Lignin-based resins for kraft paper applications

We investigated miscanthus (MS) and willow (W) lignin-furfural based resins as potential reinforcement agents on softwood and hardwood kraft paper. These resins might be sustainable alternatives to the commercial phenol-formaldehyde (PF) resins. Phenol is a petrochemical product and formaldehyde has been classified as a carcinogen by the U.S. Environmental Protection Agency. The lignin used in this study was derived from hot water extraction (160ºC, 2 h) of MS and W biomass, and may be considered sulfur-free. These biorefinery lignins were characterized for their chemical composition and inherent properties via wet chemistry and instrumental techniques. The resin blends (MS-resin and W-resin) were characterized for their molecular weight, thermal behavior, and mechanical properties. Mechanical properties were measured by the resin’s ability to reinforce softwood and hardwood kraft papers. The effect of adding hexamethylenetetramine (HMTA), a curing agent, to the resin was also examined. Mixtures of PF and lignin-based resins were investigated to further explore ways to reduce use of nonrenewables, phenol, and carcinogenic formaldehyde. The results show that lignin-based resins have the potential to replace PF resins in kraft paper applications. For softwood paper, the highest strength was achieved using W-resin, without HMTA (2.5 times greater than PF with HMTA). For hardwood paper, MS-resin with HMTA gave the highest strength (2.3 times higher than PF with HMTA). The lignin-based resins, without HMTA, also yielded mechanical properties comparable to PF with HMTA.

The Making of Particleboard from Palm Oil Fiber and Dust Wood with Epoxy as a Resin

Particleboard has been widely used in producing products such as cabinets, furniture and various home use products. In this study, epoxy resin has been used as a binder for replacing urea-formaldehyde (UF) resin which is widely used in the production of existing particleboards. Epoxy resin has strong binding properties in composing composite materials. Epoxy resin also does not release any gas as carcinogenic formaldehyde released by UF resin. The basic materials used in the production of this particleboard are palm oil fiber obtained from the Charuk Putting Palm Plant, Temerloh and dust wood obtained from the timber factory around Kuantan. The main purpose of the research scientifically known is to reduce the forest logging activities in addition to utilizing waste materials. There are 2 different size of particle material used in this study which are < 2.36mm (particle A) and 2.36mm < x < 4.75mm (particle B). The particleboard that has been produced was tested ith Universal Tensile Machine (UTM) for looking to the Modulus of Elasticity (MOE) and thickness swelling (TS). From the result, it shown that the value of Modulus of Elasticity (MOE) for particle A was 16,364 MPa while particle B was 35,578 MPa. The value of thickness swelling (TS) for particle A was 0% when it immersed for 2 hours compared o particle B which was 1.7% in the same duration. As a result of experiments, all tests have passed the minimum level of particleboard based on the Japanese Industrial Standard (JIS), 2003. Therefore, particleboard of a mixture of palm oil fiber and dust wood with epoxy as a resin can be used as a new alternative in the production particleboard for furniture industry in the future.

A Tough, Water-Resistant, High Bond Strength Adhesive Derived from Soybean Meal and Flexible Hyper-Branched Aminated Starch

Soybean meal (SM)-based adhesive exhibited a great potential to replace petroleum-derived ones to alleviate the energy crisis and eliminate carcinogenic formaldehyde. However, the bad water resistance (caused by low crosslinking density) and inherent brittleness of SM adhesive severely hindered its application. However, improving crosslinking density is generally accompanied by a toughness reduction of the adhesive. Herein, we developed a flexible long-chain starch with a hyper-branched structure (HD), and incorporated it with SM and a crosslinking agent to prepare a novel SM adhesive. Results showed that this adhesive exhibited both excellent water resistance and enhanced toughness. The wet bond strength of plywood fabricated using this adhesive was 354.5% higher than that of SM adhesive. These achievements are because introducing HD with hyper-branched groups enhanced crosslinking density, while HD’s flexible long-chain structure improved toughness of the adhesive. This HD can promote the development of tough and hydrophobic bio-based composites.

Cobalt nanoparticles encapsulated in porous nitrogen-doped carbon: Oxygen activation and efficient catalytic removal of formaldehyde at room temperature

The removal of carcinogenic formaldehyde (HCHO) to improve indoor air quality has attracted significant attention. Designing efficient catalysts for practical HCHO oxidation without use of noble metals remains challenging. In this study, metallic Co nanoparticles were encapsulated with porous nitrogen-doped carbon (Co@NC). This catalyst achieved HCHO elimination at room temperature for the first time. The as-prepared Co@NC catalyst exhibited superior catalytic activity (>80%) for HCHO removal compared with the oxidized one, and possessed the excellent stability. Theoretical calculations showed that the metallic Co in Co@NC is the active site for O2 dissociation, which enhanced the catalytic activity compared to traditional transition-metal oxides, such as Co3O4 with the high-valence state Co3+ providing active sites. The formate species was the main intermediate, which was further oxidized to CO2 as the final product. Hence, an efficient non-noble-metal catalyst for room-temperature HCHO oxidation was developed.

Development and characterization novel bio-adhesive for wood using kenaf core (Hibiscus cannabinus) lignin and glyoxal

The recent study focused on lignin-phenol-glyoxal (LPG) as an alternative way to replace toxic formaldehyde used in commercially available wood adhesives. The concern of the uses of carcinogenic formaldehyde in wood adhesive industry has become major problem over human health, environmental and economy issues. In this study, lignin isolated from Kenaf (Hibiscus cannabinus) via soda and Kraft pulping were modified into SLPG (soda lignin-phenol-glyoxal) and KLPG (Kraft lignin-phenol-glyoxal) adhesives and were compared to phenol-formaldehyde (PF). Complementary analyses such as Fourier Transform Infrared (FTIR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, thermal stability; Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were utilized to characterize all isolated lignin samples. The physical properties of the resins were further characterized in term of viscosity, gel time and total solid content. It was found that soda lignin comprised higher phenolic OH content and greater molecular weight compared to Kraft lignin. Various molar ratio of adhesives were applied on plywood and were mechanically tested. The 30% (w/w) SLPG has shown to have higher tensile strength and internal bonding stress at 72.08 MPa and 53.83 N mm−2 respectively to that of PF.

Copper-Catalyzed Tandem Multi-Component Approach to 1,3-Oxazines at Room Temperature by Cross-Dehydrogenative Coupling Using Methanol as C1 Feedstock

A copper(II)-catalyzed multi-component one-pot approach for the synthesis of 1,3-oxazines at room temperature is reported here. Methanol is used as the solvent as well as the carbon source. The methylene carbon of the oxazine product comes from methanol via formaldehyde. tert-Butyl hydroperoxide is used as the oxidant. The reaction uses an environmentally benign metal catalyst and oxidant. No inert atmosphere or precaution is required for the reaction. Most importantly, the reaction avoids the use of carcinogenic formaldehyde.

Engineering Crystal Facet of α-MnO2 Nanowire for Highly Efficient Catalytic Oxidation of Carcinogenic Airborne Formaldehyde

The activity of exposed crystal facets directly determines its physicochemical properties. Thus, acquiring a high percentage of reactive facets by crystal facet engineering is highly desirable for improving the catalytic reactivity. Herein, single-crystalline α-MnO2 nanowires with major exposed high-index {310} facets were synthesized via a facile hydrothermal route with the assistance of a capping agent of oxalate ions. Comparing with two other low-index facets ({100} and {110}), the resulting α-MnO2 nanowires with exposed {310} facets exhibited much better activity and stability for carcinogenic formaldehyde (HCHO) oxidation, making 100% of 100 ppm of HCHO mineralize into CO2 at 60 °C, even better than some Ag supported catalysts. The density functional theory (DFT) calculations were used to investigate the difference in the catalytic activity of α-MnO2 with exposed {100}, {110}, and {310} facets. The experimental characterization and theoretical calculations all confirm that the {310} facets with high ...

Integrating Mussel Chemistry into a Bio-Based Polymer to Create Degradable Adhesives

Adhesives releasing carcinogenic formaldehyde are almost everywhere in our homes and offices. Most of these glues are permanent, preventing disassembly and recycling of the components. New materials are thus needed to bond and debond without releasing reactive pollutants. In order to develop the next generation of advanced adhesives we have turned to biology for inspiration. The bonding chemistry of mussel proteins was combined with preformed poly(lactic acid), a bio-based polymer, by utilizing side reactions of Sn(oct)2, to create catechol-containing copolymers. Structure–function studies revealed that bulk adhesion was comparable to that of several petroleum-based commercial glues. Bonds could then be degraded in a controlled fashion, separating substrates gradually using mild hydrolysis conditions. These results show that biomimetic design principles can bring about the next generation of adhesive materials. Such new copolymers may help replace permanent materials with renewable and degradable adhesive...

N-Methylmelamines: Synthesis, Characterization, and Physical Properties.

N-Methylmelamines have recently gained importance as valuable compounds for manufacturing modified melamine formaldehyde resins and other polymer building blocks. A great advantage of these polymers is the reduction of the carcinogenic formaldehyde. Selecting the polymerization processes (e.g., substance polymerization, polymerization in solution) and controlling the polymerization reaction and properties of these novel materials requires knowledge of the properties of the individual melamine derivatives used as new building blocks. All possible permutations of N-methylmelamines were prepared, and reaction progress was monitored by GC/MS. 2,4,6-Tris(dimethylamino)-1,3,5-triazine was prepared to complete the series; this is, however, also a possible byproduct in various synthesis routes. The reaction conditions were optimized to obtain high yields of each derivative with the highest possible purity. The substances were characterized by NMR and IR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. In addition, physical properties, such as solubility, melting points, and pKb values, were determined. The number of amino-, methylamino-, and dimethylamino groups has a significant effect on these properties. In summary, we found that by increasing the number of amino- and methylamino groups, solubility and pKb increase. With increasing number of amino groups, the compounds tend to form hydrogen bonds, and thus, the melting point shifts to higher temperature ranges where they start to decompose.

Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL−1. The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL−1), high precision (RSD = 3.3%) and high sample throughput (144 samples h−1) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices).