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Sensitive spectrophotometric determination of trace-level Co2+ in water based on acetate enhanced catalysis of Co2+
摘要： A sensitive spectrophotometric method was developed for the determination of trace-level Co2+ in water based on the acetate enhanced catalytic decolorization of methylene blue (MB) with Co2+ as a catalyst and peroxymonosulfate (PMS) as an oxidizing agent. This indirect spectrophotometric method was easy to operate due to the strong absorption of MB at a maximum absorption wavelength of 664 nm with a molar absorptivity of 5.88 × 104 L mol?1 cm?1. Under the selected reaction conditions of 10.0 mg L?1 MB, 60.0 mg L?1 PMS and 100.0 mg L?1 Ac?, the depletion extent of MB was linearly correlated with the concentration of Co2+ from 0.20 to 7.0 μg L?1 (R2 = 0.986) and then from 7.0 to 50.0 μg L?1 (R2 = 0.991), with a detection limit (3 s/k) of 0.10 μg L?1. It was found that this method possessed excellent anti-interference capability to various coexisting ions including similar transitional metals. The developed method was used to determine the Co2+ concentration in practical samples with satisfactory results.
关键词： Spectrophotometry,Methylene blue,Catalytic decolorization,Acetate,Trace-level Cobalt
更新于2025-11-19 16:56:35
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Body Color and Morphological Correlates of Fitness in Eastern Fence Lizards (Sceloporus undulatus): A Spectrophotometric Approach
摘要： Many lizards use colorful badges in displays with conspecifics during courtship and aggressive interactions. In Eastern Fence Lizards (Sceloporus undulatus), males and females reveal sexually dimorphic ventral abdominal coloration during social interactions and use these features to signal sex and perhaps other characteristics. However, the extent to which ventral badges or other chromatic features of males and females signal quality remains unresolved in this species. Additionally, adult S. undulatus exhibit temperature-dependent color change of their abdominal badges, a potential confounding variable in studies of the function of these badges. Here, we examined the relationship between spectral variables of ventral and dorsal skin color and morphometric traits linked to fitness in adult male and female S. undulatus under standardized temperature conditions. For males, ventral patch hue tended to decrease (i.e., was blue-shifted) as body size increased, whereas dorsal hue was unrelated to male size. In contrast, there was no relationship between ventral hue and body size in females, and dorsal hue increased (i.e., was red-shifted) with body size. In males, lower ultraviolet (UV) chroma and greater blue chroma of ventral abdominal badges predicted increasing body size. In females, UV chroma of the ventral abdomen was inversely related to body size and better body condition, whereas blue chroma was inversely related to body condition only. Dorsal UV chroma decreased with increasing body size in both males and females, but brightness was not a significant predictor of any morphometric trait in either sex. Overall, these results indicate that both blue and UV reflectance of ventral and dorsal abdominal skin are indices of size and thus age, and could therefore serve as indices of signaler quality in this species.
关键词： Sexual dimorphism,Morphology,Phrynosomatidae,Spiny lizards,Spectrophotometry,Ultraviolet
更新于2025-11-14 15:30:11
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A novel method for simultaneous determination of zinc, nickel, cobalt and copper based on UV–vis spectrometry
摘要： A novel method based on UV–vis spectrometry is developed for simultaneous determination of zinc, nickel, cobalt and copper without any separation steps. The method studied in this paper is the combination of ratio spectra derivative and kalman filtering spectrophotometry. First, using absorbance of zinc standard solution as divisor, the ratio spectra derivative obtained can completely eliminate the interference of zinc on trace ions. Second, the trace ions are simultaneously determined by kalman filtering spectrophotometry. Last, based on obtaining trace ion concentrations, a calibration curve for zinc is established. The linear determination ranges are 10-70mg/L for zinc, 0.2-1.4mg/L for trace ions of nickel, cobalt and copper. The results show that the predicted results of zinc, nickel, cobalt and copper by this proposed method is superior to PLS method. The work reported here is an effective attempt for the simultaneous determination of zinc, nickel, cobalt and copper in industrial wastewater of zinc hydrometallurgy, and will have more applications.
关键词： Zinc hydrometallurgy,Ratio spectra derivative,Kalman filtering spectrophotometry,UV–vis spectrometry
更新于2025-09-23 15:23:52
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A Production-Accessible Method: Spectrophotometric Iron Speciation in Wine Using Ferrozine and Ethylenediaminetetraacetic Acid
摘要： Wine oxidation is reported to be linked to the iron species present in the wine, but spectrophotometric speciation is plagued by unstable measurements due to alterations to the reduction potential of iron by complexing agents. Ferrozine raises the reduction potential of iron by complexing preferentially to iron(II), inducing the reduction of iron(III) during analysis; here, EDTA is added to chelate iron(III) and to stabilize the forms of iron. Bisulfite addition allows the use of ferrozine for red wine analysis by mitigating color interference. Measurements agree with values from a previous method for iron(II) and from FAAS for total iron. Spike recoveries were in the range of 103.5?110.1%. The method is linear for iron concentrations in the range of 0.10?6.00 mg L?1 and offers good precision (CV 0.4?10.1%) and low limits of detection (0.02 mg L?1) and quantification (0.06 mg L?1). The method demonstrated changes to iron speciation during the oxygenation of red wines.
关键词： reduction potential,oxidation,wine,spectrophotometry,ferrozine,iron speciation
更新于2025-09-23 15:23:52
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Spectroscopy of Oxygen-Sensitive Material for Measuring Contact Lens Oxygen Transmissibility
摘要： Purpose: Oxygen permeability or transmissibility is a crucial parameter for contact lenses to ensure that extended wear will not induce corneal hypoxia. This work tests a new method of using the oxidation of cysteamine, an oxygen-sensitive chemical, to quantify the oxygen transmissibility of current commercial contact lenses and contact lenses loaded with vitamin E. Methods: 3D printing was used to modify eye drop bottles and quartz cuvettes to create systems that allowed insertion of a contact lens in between the cysteamine solution and air. Both systems were exposed to atmospheric conditions where the only path of entry for oxygen was through the contact lens. The entering oxygen reacted with cysteamine, and the rate of cysteamine oxidation was measured using UV-vis spectrophotometry. The rate was then stoichiometrically related to oxygen transmissibility. Results: The eye drop method predicted transmissibility values within 9% of established, commercial values. The cuvette method predicted values within 10% of established values for silicone hydrogel lenses without any correction factor and within 11% for poly-hydroxyethyl-methacrylate lenses after correcting for oxygen entering the system. Incorporation of 20% (w/w) vitamin E into Acuvue? Oasys? lenses did not have a significant impact on the oxygen transmissibility. Conclusions: Both methods presented in this work can reliably measure oxygen transmissibility of contacts lenses or other materials. Further improvements in manufacturing could lead to improved accuracy and reliability, allowing wider use of this method for quantifying the oxygen transport in contact lenses.
关键词： oxidation,oxygen permeability,spectrophotometry,3D printing,contact lens
更新于2025-09-23 15:23:52
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Simultaneous determination and method validation of ranitidine hydrochloride and itopride hydrochloride by UV-spectrophotometery
摘要： An UV spectrophotometric method using simultaneous equation was developed for the simultaneous determination of ranitidine and itopride in a binary mixture. In the proposed method, the signals were measured at 315.0 and 258.0 nm corresponding to absorbance maxima of ranitidine and itopride hydrochloric acid (HCl) in double distilled water, respectively. Linearity range was observed in the concentration range of 2 to 20 μg/ml for both drugs. Concentration of each drug was obtained by using the absorptivity values calculated for both drugs at two wavelengths, 315.0 and 258.0 nm and solving the simultaneous equation. Developed method was applied to laboratory mixture. The method was validated statistically and recovery study was performed to confirm the accuracy of the method. The method was found to be rapid, simple, accurate and precise.
关键词： simultaneous equation,ranitidine,spectrophotometry,Itopride
更新于2025-09-23 15:22:29
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In situ Determination of Nitrate and Hydrogen Sulfide in the Baltic Sea Using an Ultraviolet Spectrophotometer
摘要： Evaluating the health status of marine ecosystems becomes ever increasingly important especially against the backdrop of rising pressures from human activities. This is true especially for coastal seas such as the Baltic Sea that is surrounded by highly industrialized countries. Nutrients and pollutants such as nitrate and hydrogen sulfide, which have a major impact on ecosystem functioning, are two of several indicators for assessing the status of natural waters, and therefore key environmental of considerable interest. The frequency and the spatial coverage of the nitrate and hydrogen sulfide measurements are currently limited by the cost of the laboratory analysis and personnel. Optical in situ sensors can help to overcome this challenge by allowing reagentless and fast detection of dissolved chemical species. A chemical-free optical sensor has been used for direct and simultaneous measurements of both key parameters, and the results were compared with traditional methods. The data were collected during an observational program conducted in the Baltic Sea in February 2018. We used the OPUS UV spectral sensor, which was deployed for the first time in coastal waters, in combination with a deep-sea telemetry system to enable near-real time measurements during CTD profiling. Data processing was carried out using a multiple linear regression procedure. Measurements from both OPUS and on-board analysis were in good agreement. The results showed, that in situ UV-VIS spectrophotometry provides the capability to determine the concentration distributions of nitrate and hydrogen sulfide in the brackish waters of the Baltic Sea.
关键词： sulfide,Baltic Sea,monitoring,hypoxia,nutrients,UV-VIS spectrophotometry
更新于2025-09-23 15:22:29
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Optical Characteristics of Zinc Oxide Films on Glass Substrates
摘要： An algorithm is developed for solving the inverse problem of multiangular spectrophotometry of a layer on a plane-parallel substrate of finite thickness using s- and p-polarized waves. It allows the dispersive properties of the layer and substrate to be studied both far from and in the vicinity of the resonant wavelengths. The dispersive properties of layers of pure and Al-doped ZnO on glass substrates are investigated using it. It is shown that doping shifts the absorption band maximum to shorter wavelength and decreases the refractive index of the material. The applicability limits of known approximate expressions for determining the spectral dependence of the absorption coefficient of a layer from spectrophotometric data are estimated.
关键词： band gap,refractive index and absorption coefficient,multiangular spectrophotometry,ZnO
更新于2025-09-23 15:22:29
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Forensic Analysis - From Death to Justice || Usage of Infrared-Based Technologies in Forensic Sciences
摘要： Infrared (IR) radiation comprises a beam located in the electromagnetic radiation family; it arises from the thermal vibrations of radiation that have longer wavelengths than visible light, but shorter wavelengths than microwave radiation. Its wavelength is between 750 nm and 1 mm. The amount of thermal IR radiation emitted by an object is associated with the temperature of the object, the surface area of the object and the spreading of light. IR-based technologies have been demonstrated as a method of evidence identification in forensic sciences in addition to many daily uses. The combination of IR-based spectrophotometry with several techniques ushered in a new era in crime scene investigations and the identification of evidence obtained from crime scenes. Furthermore, the use of IR-based photography techniques has significant advantages. IR fluorescent automated DNA sequencer and thermal analyser for deception detection are other techniques that take advantage of IR technology. In this chapter, we aimed to present the IR-based technologies used in forensic sciences and forensic photography techniques to define the current situation, the importance and the advantages of IR thermal imaging among these techniques, as well as to describe the operating principles of IR thermal imaging technologies that may be generated in the future based on this technique.
关键词： Spectrophotometry,Scene Investigation,Post-Mortem Interval,Thermal Imaging,Infrared
更新于2025-09-23 15:21:01
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || SPECTROPHOTOMETRY/Diode Array ☆
摘要： Diode array spectrometry represents a particular approach for characterizing the result of the interaction between electromagnetic radiation and the sample, based on simultaneous measurement of light intensity over small spectral intervals having equal width. This is achieved through the following sequential stages, as schematically shown in Figs. 1 and 2D: a. interaction between the polychromatic beam and the sample; b. spatial dispersion of the transmitted (eventually reflected or emitted) radiation according to wavelength on multiple channels of equal widths, by means of a fixed optical element; c. imaging the dispersed radiation in a focal plane; and d. (quasi)simultaneous sampling of the dispersed radiation interval using photosensitive detectors, precisely positioned in the focal plane.
关键词： photodiode principle,Diode array spectrometry,concave diffraction gratings,spectrophotometry,instrumentation
更新于2025-09-23 15:21:01