Fluorescent Whitening Agents Research Articles

Integrated qPCR and Staining Methods for Detection and Quantification of Enterocytozoon hepatopenaei in Shrimp Litopenaeus vannamei.

Enterocytozoon hepatopenaei (EHP) is an obligate, intracellular, spore-forming parasite, which mainly infects the gastrointestinal tract of shrimp. It significantly hinders the growth of shrimp, which causes substantial economic losses in farming. In this study, we established and optimized a SYBR Green I fluorescent quantitative PCR (qPCR) assay based on the polar tube protein 2 (PTP2) gene for the quantitative analysis of EHP-infected shrimp. The result showed that the optimum annealing temperature was 60 °C for the corresponding relation between the amplification quantitative (Cq) and the logarithmic of the initial template quantity (x), conformed to Cq = −3.2751x + 31.269 with a correlation coefficient R2 = 0.993. The amplification efficiency was 102%. This qPCR method also showed high sensitivity, specificity, and repeatability. Moreover, a microscopy method was developed to observe and count EHP spores in hepatopancreas tissue of EHP-infected shrimp using Fluorescent Brightener 28 staining. By comparing the PTP2-qPCR and microscopy method, the microscopic examination was easier to operate whereas PTP2-qPCR was more sensitive for analysis. And we found that there was a correspondence between the results of these two methods. In summary, the PTP2-qPCR method integrated microscopy could serve for EHP detection during the whole period of shrimp farming and satisfy different requirements for detecting EHP in shrimp farming.

Monitoring of the residual moisture content in finished textiles during converting by NIR hyperspectral imaging

Hyperspectral imaging was used for large-scale monitoring of the residual moisture in wide textile webs at the end of the drying process that follows their washing or finishing by impregnation in aqueous solutions or dispersions. Such data are essential for optimizing the energy efficiency and the precise control of the drying process. Quantitative analysis of the recorded spectral data was carried out with multivariate regression methods such as the partial least squares (PLS) algorithm. Reference data for calibration of the prediction models were determined by gravimetry. The drying of textile materials from both natural or synthetic fibers possessing different water absorption capacities (cotton, polyamide, polyester), which were partially finished with an optical brightener, was investigated. Moisture contents in the range from 0 to about 12 wt% were considered in the calibration models. For all systems, the root mean square error of prediction (RMSEP) for the residual moisture was found to be about 0.5 wt%, that is, about 1 g/m2. In addition to the quantitative determination of the water content, hyperspectral imaging provides detailed information about its spatial distribution across the textile web, which may help to improve the control of the drying process. In particular, it was demonstrated that the developed methods were capable of detecting and visualizing inhomogeneous moisture distributions. Averaging of the individual values of the moisture content predicted from all spectra across the surface of the textile samples resulted in a very close correlation with the corresponding gravimetric reference values. Due to the averaging process, the difference between both values is generally lower than RMSEP even in case of samples with inhomogeneous distribution of the moisture. The high precision and the broad capabilities of the developed analytic methods for in-line monitoring of the moisture content hold the potential for an efficient process control in technical textile converting processes.

Studies on analytical method for determination of fluorescent whitening agents in paper containers for food

The method of determination of fluorescent whitening agents (FWA) in paper containers for food was studied. Samples were assessed in accordance with official procedures. The treated gauze was extracted by dimethylformamide, evaporated to dryness, and then analyzed by HPLC. The extracted FWAs were separated with Prodigy 5 μm ODS (2) column using acetonitrile: 0.01 M sodium dihydrogen phosphate (35:65) as solvent. For spectrofluorimetric detection, an excitation wavelength of 340 nm and emission wavelength of 430 nm were used. Applying the above HPLC method, fifty samples of paper containers for food were analyzed. No residue of FWA was detected in any sample.

Fluorescent brighteners in thiol-acrylate polymerizations: Sunlight-cured coatings and LED-assisted multifuctional intelligent nanoparticles synthesis

Fluorescent brighteners mediated, thiol-ene polymerizations retain the robustness of step-growth mechanism meanwhile introducing new features: biocompatible wavelengths of visible light and aqueous reaction conditions. The proposed visible-light thiol-ene polymerization of trithiol − triene monomer is shown to be an innovative, facile, and highly efficient route that constructs a versatile platform for synthesizing high-performance coatings and multifuctional intelligent nanoparticles, respectively performed in a bulk form and emulsion form. In particular, the achievement of the concept of natural-sunlight-triggered thiol-ene polymerization is extremely valuable for coating synthesis as the method is green and friendly to environment in a sustainable manner. Besides, the resulting poly(thioester) latexes are capable of being applicable as multi-stimuli-responsive nanocarriers sensitive to UV, pH and redox.

Migration kinetics of fluorescent whitening agents from polyethylene food packaging to food simulants

The fluorescent whitening agents (FWAs) could be used in polyethylene (PE) packaging to increase whiteness, little work is done to explore the pollution form PE additives to food. Therefore, this study investigated the migration of FWAs from PE food packaging to a fatty food simulant (corn oil) and aqueous ethanol food simulant. Using the determined migration data, both a Crank monolayer migration model based on Fick’s second law and a Weibull migration model were established for the FWAs. We compared the applicability of the two models to the migration tendencies of the FWAs. Both models could describe the migration behaviors of the FWAs into corn oil, the Weibull model predictions were closer to the actual migration trends. The migration behaviors of the FWAs into 95% ethanol could only be described by Crank model. In the Weibull model, the values of the parameters τ and β were positively correlated with temperature and negatively correlated with the thickness of the food packaging. In the Crank model, the partition coefficient values were positively correlated with the boiling points and negatively correlated with the polarity values. The storage conditions of the food including temperature, the thickness of PE had a tremendous impact on the migration of the FWAs in the PE. We hope this study can promote a deeper understanding of additive pollution from packaging materials to food.

Materials for D-D-A ternary organic solar cells: an absorption model study

Abstract Heterojunction solar cells based on ternary blends of two donors (absorbers and one acceptor) were investigated using modeling. The Tauc-Lorentz model and experimental absorption spectra of selected compounds were used in the simulations. The optimization process was carried out in this way to maximize the absorption of the system. Poly(3-hexylthiophene-2,5-diyl) (PEHT) was investigated as a first donor, which was mixed respectively with poly(3-octylthiophene-2,5-diyl) (P3OT), coumarin 153, purpurin, fluorescent brightener 184, N-chloroethylene carbazole, and 1,3,6,8 tetrachloro 9n amylocarbazole. Simulations were also performed for the Tauc-Lorentz model.

Rapid Detection Device of Methamphetamine Based on Improved Light Emitting Diode Induced Fluorescence Detector

In recent years, drug abuse has become a major public health problem, drug-driving poses serious threats to the public security. For the urgent need to rapidly on-site screen drug evidence and drug abusers, we have developed a fluorescent drug detection device based on LED induction (FD-LED). The core part of the device is 365 nm high-intensity LED excitation light source, FD-LED detector' performance was tested by the fluorescent brightener OB. In this study, the FD-LED detector was evaluated, and the influence of baseline noise, baseline drift, sensitivity, detection limit and quantitative limit on the detector was analyzed, the result showed that the proposed detector had good stability and sensitivity, at the same time, the chromatographic detection conditions were set, the solution based on methamphetamine C1 sample was collocated, and combined with liquid chromatography, a detection system for methamphetamine was developed. The results showed that the minimum detection amount of the sample was 1.0 × 10–9 g/ml, and the signal-concentration relationship was obvious in the range of 1.0 ng/ml∼15.6 ng/ml. This device could provide an effective method for roadside drug testing and clinical diagnosis, and give helpful assistance to law enforcement officers.

An autoanalyzer for real-time detection of benzene and volatile organic compounds in paper mills

Gas chromatography is commonly employed to detect gaseous pollutants. However, gaseous pollutants in paper mills are multicomponent and difficult to be detected and analyzed by gas chromatography. Therefore, we developed a novel autoanalyzer with an embedded supervisory system, with which multicomponent gaseous pollutants in paper mills can be detected in real time. The autoanalyzer was applied in two paper mills for the detections of the total volatile organic compounds (TVOC) and benzene at five sampling sites. The detection results show that the TVOC concentrations in two mills exceed the standard severely, especially in mill A, which can be attributed to the application of pulping and bleaching chemicals. In addition, benzene is also detected in Mill A due to benzene release from the fluorescent brighteners in the papermaking section. The large amounts of TVOC detected in the sequencing batch reactor (SBR) equalization tank of Mill A are explained by their release from the biodegradation of wastewater.

The brightest colors: A Fourier‐transform Raman, surface‐enhanced Raman, and thin‐layer chromatography‐surface‐enhanced Raman spectroscopy study of fluorescent artists' paints

AbstractAmong the so‐called “special effect” pigments, fluorescent ones play an important role, thanks to their application to a wide range of objects in everyday life. Also in the artistic field, they have been exploited since 1950s by several painters (among others Andy Warhol and Frank Stella), thus representing a particular class of materials with which conservators must confront themselves.Not much information is available about the complete composition of commercial fluorescent paints that are based on fluorescent dyes dispersed in a transparent and brittle resin. Herein, Fourier‐transform Raman spectroscopy and surface‐enhanced Raman spectroscopy (SERS) were used to recognize the main dye components of the paints, whereas thin‐layer chromatography was coupled with SERS to better distinguish further chromophore mixes responsible for the color and/or the fluorescence emission due to the presence of optical brighteners. This methodology results suitable to more fully define the composition of such fluorescent paints originally used by artists in their works, thus providing valuable information to conservators for restoration and retouching efforts.

Re-Discovering a Roman Wall Painting at Harvard: New Research on a Fragment from the Villa at Boscotrecase

ABSTRACT This article presents historical and scientific analysis, as well as the conservation treatment of a newly rediscovered Roman wall painting fragment, now in the collection of the Harvard Art Museums. Although the piece has not previously been published, it was among a group of fragments removed from a Roman villa near Boscotrecase in southern Italy, an area that has been key to the study of Roman wall painting and other decoration. Technical imaging confirms the use of painting techniques consistent with other high-quality paintings in the area. Materials analysis revealed a palette consistent with published findings of Roman wall paintings, including abundant use of Egyptian blue and green earth. Of interest was the use of Egyptian blue as an optical brightener in select white passages. Despite the high quality of the painting, no cinnabar was present, and all red passages were achieved using hematite. Multiple different white minerals were identified including calcite, aragonite, and gypsum. The widespread presence of gypsum is unusual and may point to alteration.

Determination of Chitin Content in Insects: An Alternate Method Based on Calcofluor Staining.

Chitin is an aminopolysaccharide present in yeast cells and arthropod cuticle and is one of the most abundant biopolymers. The conventional methods for the quantitation of chitin content in biological samples are based on its hydrolysis (acid or enzymatic), and the assessment of the byproduct, glucosamine. However, previously described methodologies are time-consuming, laborious, low throughput, and not applicable to insect samples in many cases. Here we describe a new approach to chitin content quantitation based on calcofluor fluorescent brightener staining of samples, followed by microplate fluorescence readings. Calcofluor is a specific chitin stain commonly used for topological localization of the polymer. The protocol was tested in three important disease vector species, namely Lutzomyia longipalpis, Aedes aegypti, and Rhodnius prolixus, and then compared to a classic colorimetric chitin assessment method. Results show that chitin content in the tested insects can vary largely in a range of 8–4600 micrograms of chitin per insect, depending on species, sex, and instar. Comparisons between measurements from the previous protocol and calcofluor method showed statistically significant differences in some samples. However, the difference might be due to interference in the classic method from non-chitin sources of glucosamine and reducing agents. Furthermore, chitinase hydrolysis reduces the total chitin mass estimated between 36 and 74%, consolidating the fluorescent measurements as actual stained chitin in the same extent that was observed with the standard protocol. Therefore, the calcofluor staining method revealed to be a fast and reliable technique for chitin quantitation in homogenized insect samples.

Quaternary ammonium salt ion pair reagent sensitizing for determination of fluorescence whitening agent 85 in paper food packaging.

Fluorescent whitening agents (FWAs) are added to food packaging during manufacture to improve the whiteness and brightness. It is of great significance to develop a fast and sensitive FWAs detection method because their potential hazards to human health. Herein, we found that the quaternary ammonium salt ion pair reagents could enhance the fluorescence of FWAs, and then developed a fluorescent determination method for FWA 85 in paper food packaging. Under the optimized conditions, the linear range for the determination of FWA 85 was 5-200ng/mL (R2=0.9996). The limit of detection was 1.20ng/mL (S/N=3) and the limit of quantitation was 3.99ng/mL. The analytical feasibility was investigated further via determination of FWA 85 in paper food packing, which shows the recoveries were varied from 83.84% to 115.29% with RSDs from 1.64% to 7.22%. The method provides a new quaternary ammonium salt ion pair reagent sensitization for the detection of FWAs in paper food packaging.

Archroma completes purchase of Indian optical brighteners business

Archroma completes purchase of Indian optical brighteners business

Cu2+ sensing via noncovalent complexes of fluorescent whitening agents and imidazole‐based polymeric dye transfer inhibitors

ABSTRACTFluorescent whitening agents (FWAs) and polymeric dye transfer inhibitors (DTIs) are widely used in detergent formulations to combat garment yellowing, fading, and discoloration. We report a new application for these inexpensive, mass‐produced, laundry additives as sensitive fluorescence “turn‐off” sensors for Cu2+. We show that Cu2+‐sensitive FWA–DTI complexes form spontaneously when aqueous solutions of FWA and imidazole‐based DTI are mixed. We also show that the imidazole groups present in the resulting fluorescent FWA–DTI complex selectively bind Cu2+, a potent fluorescence quencher, to form nonfluorescent FWA–DTI‐Cu2+ complexes. Our Cu2+‐sensing FWA–DTI complexes are completely water‐soluble and have a Cu2+ detection limit of ~ 0.14 μM in water. Our simple approach not only converts the Cu2+‐insensitive FWAs into sensitive fluorescent probes for the metal ion but also significantly enhances the brightness of triazinylaminostilbene FWAs. The present study provides a facile, synthesis‐free strategy for producing inexpensive fluorescent sensors for Cu2+. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48915.

Influence of Optical Brightening Agent Concentration on Properties of Cotton Fabric Coated with Photochromic Microcapsules Using a Pad-Dry-Cure Process.

The weak photostability of photochromic dyes applied to textile substrates is one of the disadvantages of the broader use of photochromic dyes in the textile industry. Therefore, the influence of optical brightener concentration on both the photocoloration and photostability of cotton fabric coated with photochromic microcapsules using a pad-dry-cure process, as well as the physical-mechanical properties and colorfastness properties, were studied in this research. Coated samples were subjected to different tests according to valid EN ISO standards; namely mass per unit area, fabric stiffness, breaking force and elongation, air permeability, and different colorfastness properties (rubbing, domestic and commercial laundering, and light). Results showed that the coated fabric had higher mass per unit area, stiffness, breaking force and elongation and lower air permeability compared to uncoated fabric, irrespective of the padding bath composition. Coated fabric has better colorfastness to wet than dry rubbing. The colorfastness to washing decreases with the increased number of washing cycles. The use of optical brightener decreases the photocoloration of coated fabric and increases the photostability of coated fabric after the exposure of samples to a Xenotest apparatus for longer than 12 h.

Effective extraction of fluorescent brightener 52 from foods by in situ formation of hydrophobic deep eutectic solvent

Fluorescent brightener 52 (FWA52) is a coumarin-based compound, and it is difficult to degrade owing to its high chemical stability. Up to now, several methods have been developed to extract and determine FWAs, but toxic, volatile and harmful organic solvents are often used. In this paper, a novel method for the extraction and analysis of FWA52 is proposed for the first time by in situ formation of hydrophobic deep eutectic solvent (DES) with parabens in aqueous solution. The effects of paraben structure, solution pH, system temperature, extractant dosage and initial FWA52 concentration on the extraction recovery were investigated systematically. It is shown that FWA52 can be extracted by 2-ethylhexyl 4-hydroxybenzoate at ultra-trace level (0.05 μg/L FWA52) at room temperature without using harmful organic solvents, and various coexisting inorganic ions and organic compounds have little effect on the extraction efficiency. Based on these results, a novel and simple strategy is developed for the accurate determination of FWA52 in water. It is found that under the optimal experimental conditions, the linear range of this method is 0.20~25 μg/L (R2 = 0.9995), and the detection limit and the quantity limit are 0.045 μg/L and 0.20 μg/L respectively. This method has been successfully applied for the determination of FWA52 in actual food samples and food contact materials, such as noodles, fish balls, mushroom and paper cups, with a recovery from 82 to 113% and a relative standard deviation (RSD) from 4.7 to 9.9%. In addition, the separation mechanism was investigated by FT-IR and 1H NMR, and was discussed from strong hydrogen bonding between FWA52 and 2-ethylhexyl 4-hydroxybenzoate and the formation of corresponding DES.

Bioimaging structural signatures of the oomycete pathogen Sclerospora graminicola in pearl millet using different microscopic techniques

In this case study, the mycelium growth of Sclerospora graminicola in the infected tissues of pearl millet and the process of sporulation and liberation of sporangia and zoospores were observed using four different microscopic techniques. The cotton blue-stained samples observed under light microscope revealed the formation of zoospores with germ tubes, appressoria and initiation of haustorium into the host cells, while the environmental scanning electron microscopy showed the rapid emergence of sporangiophores with dispersed sporangia around the stomata. For fluorescence microscopy, the infected leaf samples were stained with Fluorescent Brightener 28 and Calcofluor White, which react with β-glucans present in the mycelial walls, sporangiophores and sporangia. Calcoflour White was found to be the most suitable for studying the structural morphology of the pathogen. Therefore, samples observed by confocal laser scanning microscopy (CLSM) were pre-treated with Calcofluor White, as well as with Syto-13 that can stain the cell nuclei. Among the four microscopic techniques, CLSM is ideal for observing live host-pathogen interaction and studying the developmental processes of the pathogen in the host tissues. The use of different microscopic bioimaging techniques to study pathogenesis will enhance our understanding of the morphological features and development of the infectious propagules in the host.

Anthropogenic markers for source tracking of fecal contamination in Bayou Lafourche: a major drinking water source in Southeast Louisiana, USA

Abstract Bayou Lafourche, which is the sole drinking water source for 300,000 people in Louisiana, has failed to consistently meet its designated use criteria set by the Louisiana Department of Environmental Quality (LDEQ). This resulted in a total maximum daily load to be imposed on the Bayou by the Environmental Protection Agency (EPA). These designated use water quality criteria include fecal coliform (FC) levels for drinking water source, primary contact recreation, and secondary contact recreation. The goal of this study was to identify and enumerate anthropogenic nonpoint source FC contamination from malfunctioning home sewage systems in the Bayou's watershed. Thirty-four sites along the Bayou were selected for the study. Samples were analyzed for optical brightener ratios, FC CFU/100 mL (mFC), Escherichia coli, and three human markers, including human polyomavirus BK, the Archaeon Methanobrevibacter smithii, and the human-associated Brevibacterioides HF 183 eubacteria. Frequencies of sites with all three anthropogenic molecular markers are considered positive for human fecal contamination. This study provided data to address the problem of malfunctioning on-site sewage systems in the Bayou Lafourche watershed.

Preparation and Properties of Chitosan/Graphene Modified Bamboo Fiber Fabrics.

Chitosan (CS) and graphene (Gr) were used to modify bamboo fiber fabrics to develop new bamboo fiber fabrics (CGBFs) with antimicrobial properties. The CGBFs were prepared by chemical crosslinking with CS as binder assistant and Gr as functional finishing agent. The method of firmly attaching the CS/Gr to bamboo fiber fabrics was explored. On the basis of the constant amount of CS, the best impregnation modification scheme was determined by changing the amount of Gr and evaluating the properties of the CS/Gr modified bamboo fiber fabrics. The results showed that the antibacterial rate of CGBFs with 0.3 wt% Gr was more than 99%, and compared with the control sample, the maximum tensile strength of CGBF increased by 1% in the longitudinal direction and 7.8% in the weft direction. The elongation at break increased by 2.2% in longitude and 57.3% in latitude. After 20 times of washing with WOB (without optical brightener) detergent solution, the antimicrobial rate can still be more than 70%. Therefore, these newly CS/Gr modified bamboo fiber fabrics hold great promise for antibacterial application in home decoration and clothing textiles.

Visual cues from different trap colours affect catches of Sahlbergella singularis (Hemiptera: Miridae) in sex pheromone traps in Cameroon cocoa plantations

Cocoa mirids, Sahlbergella singularis and Distantiella theobroma, are the most economically important insect pests of cocoa in West and Central Africa, where they can cause up to 40% losses in cocoa yields. Sahlbergella singularis is the most common species in Cameroon and was therefore targeted in this study. During a two-year trial in 15 cocoa plantations in Ayos and Konye, in the Centre and Southwest regions of Cameroon respectively, the most effective colour – white, purple or green – of sex pheromone traps was examined for integration into mirid management programmes. Similar temporal patterns in S. sahlbergella male trap catches were observed with all three colours, but the green trap caught more S. singularis (Ayos: 0.968 ± 0.091 [SEM]; Konye: 0.640 ± 0.076/trap/month) compared with purple traps (Ayos: 0.674 ± 0.068; Konye: 0.441 ± 0.058), and white traps (Ayos: 0.467 ± 0.049, Konye: 0.253 ± 0.041). Trap reflectance showed wavelength peaks typical for purple in both short (approximately 380–480 nm) and long wavelengths (>650 nm), and ~530 nm for green. Reflectance peaks exceeded 100% of the incident light in the 400–450 nm range from the white, suggesting the presence of optical brighteners. Trap catches support the hypothesis that S. singularis ocelli are more responsive to light of shorter wavelengths. Despite the low attractiveness of the sex pheromone to S. singularis, a optimisation of the colour of the trap can improve S. sahlbergella monitoring, mass trapping, and other control measures which could ultimately lead to reductions of insecticide use and to conservation of beneficial arthropods, particularly cocoa flower pollinators that are critical for improving cacao tree productivity.