Color Reaction Research Articles

Inter- and intra-plant variation in phenol content in grains of rice (Oriza sativa varieties using phenol colour reaction

Different stages of phenol colour reaction showed induction of phenol colour reaction occur post anthesis, i.e. stage 2. In the later stages, i.e. stage 3 (dough) and 4 (harvest maturity) seeds showed similar phenol reaction with less intensity. Phenol content estimated at different stages of growth and maturity showed the highest at post fertilization stage, i.e. stage 2 and it decreased in stage third and fourth. Inter-panicle phenol content was not significantly different whereas intra-panicle difference in phenol content was observed.

Antioxidant identification using a colorimetric sensor array based on Co-N-C nanozyme

Here we develop a simple and effective nose/tongue sensor array based on Co-N-C single-atom nanozymes-3,3′,5,5′-tetramethylbenzidine (TMB)-H2O2 for colorimetric discrimination of antioxidants, which makes use of the color reaction of TMB oxidation by H2O2 in two different pH (3.8 and 4.6) environments under the catalysis of Co-N-C nanoenzyme with peroxidase-like activity. Different antioxidants have varying reducing ability to the oxidation products of TMB (oxTMB), thus resulting in differential absorbance and color changes. Linear discriminant analysis (LDA) results indicate that the sensor array successfully identified 7 antioxidants, i.e., glutathione (GSH), ascorbic acid (AA), cysteine (Cys), tannin (TA), Catechin (C), dopamine (DA), and uric acid (UA) in both buffer and even serum samples. Additionally, the performance of the sensor array was validated with antioxidant mixtures, individual antioxidants with different concentrations, and target antioxidants and interfering substances. In general, the versatile sensor array based on Co-N-C single-atom nanozymes provides an excellent strategy for identifying a variety of antioxidants, which exhibits a broad application prospect in medical diagnosis.

Optimization of acquisition parameters of slurry coating characteristics based on multiple yarn simultaneous detection

A simultaneous detection method was proposed to detect slurry coating characteristics based on the same spatial resolution of starch-based sized and raw yarns. A dynamic image acquisition device was improved to capture the apparent images of multiple yarns simultaneously after the starch–iodine color reaction. The slurry coating characteristics were calculated utilizing image-processing technology. For the sake of effective and stable detection, the effects of illumination conditions on the concentration of I2-KI solution were studied through the absorbance value test. The effects of image-processing parameters on the experimental results were analyzed respectively by measuring six kinds of yarn of different counts and size pick-up. The results showed that the illumination conditions within an illumination time of 0–60 min, illumination intensity of 0–80,000 lux and illumination distance of 0.01–0.20 m had no significant effects on the concentration of I2-KI solution. Eight rows of pixels in the central axis areas of the yarn were determined as the effective statistical areas. It was determined that the sample size can meet the needs of stability test in 200 pieces. A dynamic threshold method, which served the intersection of the gray histogram of sized and raw yarn under the same spatial resolution as the threshold, can effectively segment the slurry coating areas. On the above basis, the optimization acquisition parameters of the detection method were obtained. The proposed method can meet the requirements of the efficiency test, common applicability and ease of operation.

Preparation of pH‐indicator films based on soy protein isolate/bromothymol blue and methyl red for monitoring fresh‐cut apple freshness

Intelligent pH-indicator films based on soy protein isolate (SPI) were prepared using pH-sensitive dyes (bromothymol blue and methyl red). The addition of mixed indicators imparts pH-indicator films with an appreciable microstructure, acceptable water resistance, and favorable optical properties. The incorporation of the mixed indicators did not lead to significant improvement in the mechanical properties of films due to weak ionic cross-linking by hydrogen bonding between the SPI macromolecules and low-molecular-weight indicators. Fourier-transform infrared spectroscopy indicated hydrogen bond-mediated intermolecular interactions, and scanning electron microscopy showed that BB/MR were well dispersed in the SPI film. The indicator addition hindered the sorption and passage of water molecules. The water vapor permeability, moisture sorption, moisture content, and total soluble matter were 4.32 to 6.12 ×10-12 g·cm/cm2 ·s·Pa, 36.70% to 73.33%, 25.28% to 44.11%, and 8.21% to 25.56%, respectively. Also, the addition of indicators reduced UV light transmittance with minimal effect on the transparency of the film. The presence of indicators enhanced the pH sensitivity, seen as a visible color reaction at different pHs (total color difference, ΔE>5). When the pH-indicator film containing 8ml/100ml final film emulsions was used to monitor the fresh-cut apple freshness, a green color for fresh status was observed, which turned blue after 60h. Collectively, our findings suggested that indicator-containing SPI films have the potential for monitoring the freshness of fruits. PRACTICAL APPLICATION: pH-indicator films can help consumers to identify the freshness of packaged food by a change in the color of the packaging material, which is easily visible to the unaided eye without the need for opening the packaging. This protects consumers' interests.

Co-MOF-74 based Co3O4/cellulose derivative membrane as dual-functional catalyst for colorimetric detection and degradation of phenol

Smart nanomaterials that can simultaneously detect and eliminate contaminants in water environment are significant for health protection. To achieve such goal, Co-MOF-74 was in-situ assembled on regenerated cellulose membranes followed by calcination process, thus achieving dual-functional Co3O4/cellulose derivative membrane (Co3O4/CDM) catalyst. The Co3O4 morphology was readily controlled by further recrystallization of the deposited MOF precursor. Combining the high enrichment ability of cellulose membrane and outstanding peroxidase-active of Co3O4, the fast color reaction for phenol was accomplished within 10 min by Co3O4/CDM with the assistance of H2O2 and 4-aminoantipyrine (4-AAP). Moreover, the Co3O4/CDM also portrayed an excellent degradation property for phenol elimination via sulfate radical-advanced oxidation processes (SR-AOPs). The degradation efficiency of phenol reached 93% in 20 min, and the possible mineralization mechanism was proposed based on the XPS and LC-MS analysis. Thus, Co-MOF-74 derived Co3O4/CDM shows excellent properties in aiding the colorimetric detection and degradation of phenol in aqueous solutions.

Paper-Based Analytical Device for the On-Site Detection of Nerve Agents.

We report a colorimetric paper-based microfluidic device based on an enzyme inhibition assay that allows the on-site detection of nerve agents by sampling and wicking. The sample and reagents are automatically transported through the channel where an enzyme inhibition reaction is conducted, followed by an enzyme-substrate reaction and a color reaction. This device can detect 0.1 μg/mL of the nerve agent VX in a 2.5 μL drop and is nerve agent selective and robust against temperature, pH, and several liquids. We confirmed that sampling procedures (dilution and wiping) are applicable to this device. Furthermore, the fabrication procedure is easy, and the cost is at most a few tens of cents. Thus, the present device provides a practical method for the urgent detection of nerve agents in suspected chemical terrorism incidents.

Various Natural Dyes Using Plant Palette in Coloration of Natural Fabrics

The use of natural dyes in textile coloring has shown a growing interest. Many countries have developed stringent environmental rules to respond to hazardous and allergic synthetic coloring reactions. Since there is a growing need for these ecologically friendly wool yarns, cotton, and silk, there are enormous regions for novel color sources. In the following content, several innovative natural dye sources are explored. New coloring features such as quickness and natural dyeing were also applied. Natural dyes form plants are become more popular in textile coloring. This is because the poisonous and allergic synthetic tinting responses have enforced strict environmental rules in many nations. During this review using of natural dyes extracted from plants and its application on textile materials were investigated.

Detection of Heavy Metal Pb in Cosmetics at Traditional Market of Banjarmasin

Background: Impurities produced from the basic ingredients of making cosmetics, one of which is lead (Pb). Lead is a substance that is harmful and toxic to the human body. Lead can affect the hematopoetic system, nervous system, reproductive system, endocrine system and is carcinogenic. Objective: To determine the presence of lead (Pb) heavy metal contamination in mascara products circulating in the Banjarmasin traditional market. Methods: This study used a descriptive observational method. Testing qualitatively using KI, NaOH, and HCl reagents. Results: The test results obtained from the sample after being reacted with the three reagents showed a positive presence of lead (Pb) heavy metal. With KI solution shows a yellow-black precipitate, with NaOH solution shows a white precipitate and with HCl solution shows a white precipitate. Conclusion: Qualitative tests on mascara cosmetic products taken at different points of sale in the Banjarmasin traditional market using color reagents in KI solution, NaOH solution, and HCl solution, it can be concluded that the qualitative test results show a positive presence of heavy metal lead (Pb). on mascara products.

Identifikasi Golongan Senyawa Flavonoid Ekstrak Etanol Daun Anting-Anting (Acalypha indica L.)


 
 
 
 Anting-anting leaf is one type of plant that has medicinal properties and has not been widely used by the community. Previous research stated that the ethanol extract of Anting-anting has secondary metabolite compounds such as saponins, flavonoids, alkaloids, tannins. Flavonoids are a source of antioxidants that can inhibit premature aging caused by free radicals produced by pollution. Flavonoids can be used to avoid deadly diseases including heart disease and cancer. The purpose of this study was to determine the class of flavonoid compounds present in anting-anting leaf (Acalypha indica L.). The method used in this study was a color reaction, the material used was anting-anting leaf (Acalypa indica L.), CH3COONa. , FeCl3, Na2CO3, NaOH 0.1 N, CH3COOPb, H2¬SO4. The results of this study indicate that the Anting-anting extract (Acalypa Indica L.) positively contains flavonoids of the anthocyanidin group, using Na2CO3 reagent, the color formed is green, and positive contains flavonol and flavone groups using H2SO4 and NaOH reagents, the color formed is yellow. 
 
 
 

A Simplified Procedure for Cellulase Filter Paper Assay

A new procedures to minimize labor intensiveness and complexity that has long been recognized in cellulase filter paper activity measurement (FPAase) described by the international union of pure and applied chemistry (IUPAC) was developed. It follows the main idea of IUPAC finding at least two cellulase dilutions have optical densities slightly more and less than a reference optical density of an arbitrary fixed 2 mg absolute glucose amount after a red-ox color reaction and due to cellulase-filter paper hydrolysis. The yielding glucose amount difference as compared to this reference is expressed in terms of absorbance difference percent determined by 3,5-dinitrosalicylic acid (DNS), in case of cellulase is cellubiase rich. If not, an external supplemental portion should be added. The intersection of the line of these two cellulase dilutions with abscissa intersect a vertical at a hypothetical 0% absorbance difference percent corresponding to a critical cellulase dilution exactly release this fixed arbitrary 2 mg glucose amount value. The factor 0.37 of this critical cellulase dilution equals to its filter paper units expressed in FPU per ml. A cellulase Cellic Ctech2 from novozymes has been tested with this methodology giving a satisfactory results with IUPAC procedures.

Chemical Characterization and in Vitro Antioxidant Activity of Honey from Different Localities of Côte D’ivoire

Aims: Although the honey produced in Côte d'Ivoire is widely used in households, there is no technical sheet mentioning its chemical composition. Thus, the present study aimed to fill this gap while studying the chemical composition and antioxidant power of eleven honey samples from nine localities in Côte d'Ivoire.
 Methodology: The identification of secondary metabolites in the different honey samples was carried out by TLC and by color reaction tests. The quantification of these was performed by spectrophotometry. The antioxidant power of the honey samples was studied by DPPH and FRAP methods.
 Results: All honey samples contains secondary metabolites from various families, with varying contents of total phenolic compounds and flavonoids. Overall, the honey samples showed a notable antioxidant profile, making them good free radical scavengers. The relationship established between the different variables analyzed showed in some cases positive and significant correlations.
 Conclusion: The results of this study show that the honey produced in Côte d'Ivoire is of good quality. Therefore, its recurrent consumption could contribute to fighting certain pathologies caused by oxidative stress.

Research on copper erosion in hydrogen peroxide/kerosene bipropellant thrust chamber

The severe erosion in the bicomponent propellant heat sink thrust chamber of hydrogen peroxide and kerosene through the firing test is studied. As shown in the results of CT scanning, the copper lining is burned through to expose a large gap between the copper lining and the stainless-steel shell. The erosion area of cross-section of copper lining decreases as the distance from the chamber head along the axial direction increases. During the firing test, the color of flame changes to green at 6.78s and after 9.34s the flame continues to be green. The temperature of the flame is obviously higher than that of normal combustion flame. It is considered as the flame color reaction of copper. The temperature of the burning gas reaches about 2640 K. Therefore, there is a phase change of copper lining, i.e., the loss of liquid copper on the surface under short-time operating conditions. Due to incomplete catalysis, the liquid hydrogen peroxide accumulates in the combustion chamber and is catalyzed by pure copper. It will cause the inner wall to be burned through to expose a hole. Thus, it is significant to adopt a catalytic bed of fast response and high efficiency, optimize the time sequence of pulse test, and select the compatible materials instead of copper for the chamber lining, for the purpose of improving the stability of heat sink thrust chamber. This paper is designed to break through the key technology of multiple starts and long-time operating conditions of hydrogen peroxide/kerosene bipropellant engine.

A color reaction for the determination of Cu2+ in distilled beverages employing digital imaging

In this work, we describe for the first time the synthesis of a thiocarbazone for the selective determination of Cu2+ in distilled beverages. The method was based on the complexation reaction of Cu2+ with the thiocarbazone, and the colored product was analyzed using a smartphone application. The thiocarbazone reacts with Cu2+ to form a 1:1 (metal:ligand) complex. The Cu2+ complex was characterized by UV, IR and NMR spectral analyses. The proposed reaction yields a yellow color, and therefore, channel B of the RGB system was used in the analysis. After optimizing the reaction conditions, an analytical curve was obtained to determine Cu2+ concentrations ranging between 0.25 and 6.75 mg L−1; the use of 400 μL sample volumes led to a relative standard deviation (n = 5) of 3.2% and a detection limit of 0.18 mg L−1. Recovery experiments were performed with sugar cane spirits, whiskies and tequilas to evaluate the accuracy of the method, and the recovery obtained ranged from 80.5 to 112.2%.

Atomically Dispersed Manganese Lewis Acid Sites Catalyze Electrohydrogenation of Nitrogen to Ammonia

Atomically Dispersed Manganese Lewis Acid Sites Catalyze Electrohydrogenation of Nitrogen to Ammonia

A field‐friendly method of measuring faecal glucocorticoid metabolite concentration as a simple stress checker in snow leopards

Abstract The hormonal analysis of excrement has been employed to non‐invasively assess the physiological conditions of domestic, experimental, zoo and wild animals to. However, conventional hormone analysis techniques require frozen and refrigerated reagents, and laboratory equipment; therefore, it is almost impossible to obtain the results on‐site. This study attempted to establish a method for the simple and rapid quantitative on‐site analysis of faecal glucocorticoid metabolite (fGM) concentrations; this method involved using hand‐shaking for faecal hormone extraction, and immunochromatography using test strips and a smartphone application. This study focused specifically on snow leopards and developed a new, simple fGM measurement method to evaluate their stress levels on‐site. First, the effects of ultraviolet exposure and bacterial activity on fGM concentration, including sample age, were evaluated using faeces from a captive snow leopard. Second, a field‐friendly hormone extraction method was evaluated; this method does not require storage of faeces in the field because the hormones are extracted by hand‐shaking of faeces in ethanol at the time of collection. In addition, to measure hormone concentrations on‐site, a simple immunochromatography measurement kit was used. The concentrations were measured by quantifying the colour reactions using a smartphone application. There was no consistent increase or decrease in fGM concentration with ultraviolet irradiation time. In addition, a high correlation was observed between concentrations extracted using the conventional method (using a vortex mixer and methanol extraction) and those from the field‐friendly method (r = 0.812, p < 0.05). Changes in fGM concentration measured using immunochromatography were also highly consistent with those measured using the conventional method (enzyme immunoassay; r = 0.825, p < 0.05). The analytical validation of immunochromatography also showed high accuracy, that is parallelism (ANCOVA: F = 0.597, df = 1, p = 0.445) and recovery tests (98.2% ± 5.1% and 107.5% ± 18.7%). Further, for biological validation, the change in fGM concentration was examined before and after the transportation of the snow leopards to another zoo. This field‐friendly hormone analysis method is expected to contribute as a simple and rapid stress evaluation tool to manage conservation and animal welfare by monitoring the stress levels.

Determination of nitric oxide using light-emitting diode-based colorimeter with tubular porous polypropylene membrane cuvette.

On the basis of the Griess-Saltzman (GS) reaction, an optical device for nitric oxide (NO) detection in exhaled breath and atmosphere was developed by employing the light-emitting diode (LED, 560nm) as the light source, light-to-voltage converter (LVC) as the detector, and porous polypropylene membrane tube (PPMT) as the cuvette. The PPMT was filled with GS reagents and covered with a coaxial jacket tube for gas collection and color reaction; two ends of the PPMT were connected with the LED and LVC to detect the change of light transmissivity in the wavelength range of 530 to 590nm mainly. A gas absorber filled with GS reagents was installed prior toanother absorber filled with KMnO4 solution to eliminate the interference of coexisting NO2. Under the optimized experimental conditions, the device achieved a limit of detection (3σ/k) of 4.4ppbv for NO detection. The linearity range of this device was divided into two segments, i.e., 25 to 100ppbv and 50 to 1000ppbv, with both coefficients of determination > 0.99. The relative standard deviation was 2.7% (n = 9, c = 100 ppbv), and the analytical time was 5.5min per detection. The minimum detectable quantity was decreased to 1.18ng, which was ~ 100 times lower than the original GS method (115ng). The present device was applied for determination of NO in exhaled breath, vehicle exhaust, and air. In addition to satisfactory spiking recoveries (i.e., 103% and 107%), the analytical results of the present device were in agreement with the results obtained by the standard method. These results assured the practicality of the developed device for NO detection in real environmental samples.

Antituberculosis Activity of Parang Romang (Boehmeria virgata (Forst.) Guill) Stem Extract

Parang Romang (Boehmeria virgata (Forst.) Guill) is one of the plants empirically used by the people of South Sulawesi. This study aimed to test the activity of Parang Romang Extract against Mycobacterium tuberculosis. The 96% ethanol extract obtained was fractionated by the liquid-solid extraction method: obtained n-Hexan soluble extract and n-Hexan insoluble extract. Samples of 96% ethanol extract, soluble extract of n-Hexan and insoluble extract of n-Hexan were made in series of concentrations of about 25, 50, 75, and 100 µg/ml. The inhibition test of Mycobacterium tuberculosis used the MODS method on the Mycobacterium tuberculosis strain H37RV. Color reagents then identify extracts that provide inhibition. The results of the minimum inhibition concentration of Mycobacterium tuberculosis showed that a 100 µg/ml of n-Hexan soluble extract was able to inhibit the growth of Mycobacterium tuberculosis strain H37RV.

Colorimetric and Electrochemical Dual-Signal Method for Water Toxicity Detection Based on Escherichia coli and p-Benzoquinone.

The development of simple and rapid toxicity detection methods has important practical significance. In this work, a dual-signal method with colorimetric and electrochemical properties for water toxicity detection was proposed for the first time based on a rapid color reaction between Escherichia coli (E. coli) and p-benzoquinone (BQ). Here, E. coli was used as a biocatalyst and BQ was used as a mediator. An IC50 value of 0.75 mg L-1 for Cu2+ was obtained using a two-step electrochemical detection method. Strikingly, toxicity could also be estimated visually by the naked eye, and the minimum detection limit was 3.2 mg L-1 for Cu2+. The dual-signal toxicity detection method extends the function of BQ, and the result is more reliable than the traditional single-signal method. This simple and rapid toxicity detection method shows certain application prospects.

Shallot skin profilling, computational evaluation of physicochemical properties, ADMET, and molecular docking of its components against P2Y12 receptor.

Medicinal plants are a source of many compounds that are useful in the pharmaceutical field for novel drug development. Polyphenols and the flavonoid group in plants are known to have several activities, such as relieving cardio vascular disease (CVD). The outer skin of the shallot which is disposed of as waste is known to have an antiplatelet activity which was tested in vitro assay. To date, there is no study reported on the ADMET profile and physicochemical properties of the active component of the shallot skins. The extraction of shallot skins was conducted by ultrasonic irradiation using ethanol. The phytochemical screenings were carried out by TLC and color reaction. The profiling of its active ingredient was presented by GC-MS, HPLC and spectrophotometry UV-vis. Whereas their physicochemical properties were analyzed by ChemDraw 17.00 program and the ADMET predictions were studied using pkCSM online tool. The MVD program was operated in the docking study on protein P2Y12 (PDB ID 4PXZ). The extract showed the presence of polyphenol, flavonoids, quercetin, natalensine-3,5-dinitrobenzoate; bis[2-(2-fluorophenyl)-6-fluoroquinolin-4-yl]amine, benzo[a]heptalene, N-(trifluoroacetyl) methyl-N-deacethyl-colchicine. The ADMET prediction data displayed that the compounds in the extract have good absorption so that they can be used in the oral and transdermal routes. Some components in the extract have lower MDS than clopidogrel. The ultrasonicated shallot skin extract can be used as additional resources of the active pharmaceutical ingredients and to have the potency to be developed as an oral or transdermal preparation.

A spore-based portable kit for on-site detection of fluoride ions

The excess residues of fluoride ions cause serious human health problems, making their detection highly valuable. In this work, a whole-cell-based biosensor was presented for the detection of fluoride ions, which can inhibit the color reaction of 3,3′,5,5′,-tetramethylbenzidine (TMB) catalyzed by the CotA-laccase of spore surface. This reaction for the detection of fluoride ions could be read out through UV–vis spectrophotometer, smartphone, or standard colorimetric card within 10 min. Under optimum conditions, a linear range of 1–600 μmol L–1 with a detection limit of 0.12 μmol L–1 (3σ/k) was achieved for fluoride ions detection by using UV–vis spectrophotometer. The biosensor coupling with smartphone had a good linear response to fluoride ions concentration in the range of 5–600 μmol L–1 with LOD of 0.90 μmol L–1 (3σ/k). The standard colorimetric card can be directly used for recognizing the fluoride ions level via naked-eyes. A portable kit based on a colorimetric card and smartphone was developed and has been successfully applied for fluoride ions monitoring in surface waters and groundwater. This developed method has several advantages such as rapid, outstanding selectivity and anti-interference, low-cost, ease of operation and storage, and eco-friendliness, meeting the demands of point-of-care testing of fluoride ions and disease prevention.