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Dose response and stability of water equivalent PRESAGE <sup>?</sup> dosimeters for synchrotron radiation therapy dosimetry
摘要： This research investigated the dose response and post-irradiation stability of water-equivalent PRESAGE? dosimeters exposed to synchrotron radiation. Water-equivalent PRESAGE? dosimeters were irradiated up to 1000 Gy in a synchrotron x-ray beam with a mean energy of 95.3 keV. The change in optical density was measured using UV/visible spectrophotometry pre- and post-irradiation using a wavelength of 630 nm. Dose response was found to be approximately linear from 0–200 Gy with saturation occurring above 300 Gy. The post-irradiation stability was determined by measuring the change in optical density at 10, 30, 60, 180, 420 min and 7, 21 and 33 d post-irradiation for three groups of dosimeters stored at different temperatures. Each group had two dosimeters irradiated at 50, 100, 200 and 300 Gy and each group was stored at a different temperature following irradiation: room temperature (22 °C), 4 °C and ?18 °C. The optimal time for readout of the dosimeters varied with the post-irradiation storage temperature. The room temperature group had an optimal time-to-readout of 10 min for maximum signal before fading, while the 4 °C group was reasonably stable from 90 min to 1 week. The ?18 °C group showed the least amount of ongoing post-irradiation development and fading with an optimal readout window from 30 min to 21 d. The intra-batch variation between the mean of each temperature control group was 4.2% at 10 min post-irradiation.
关键词： PRESAGE? dosimeter,synchrotron radiation therapy,UV/Vis spectrophotometry
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) 2ND INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE) - Yogyakarta, Indonesia (14 August 2018)] - Validation on analysis method for phosphorus in solid inorganic fertilizer using UV-visible spectrophotometry
摘要： Determination of performance and uncertainty parameters from P2O5 analysis in inorganic fertilizer conducted by spectrophotometric UV-Visible has been done. This method was conducted in three stages those were preparation, testing and data processing. In the preparation stage, standard solution and reagent solution was made and for the testing stage, phosphorus standard and P2O5 samples were taken from inorganic fertilizer with linearity, precision (repeatability), accuracy (% recovery), limit of detection and limit of quantitation as variable analysis. The stage of data processing, the obtained results were processed statistically and compared with the acceptance requirements set by standard method. The coefficient determination (R2), precision, and accuracy respectively were 0.9999, 0.174%, and 100.58%, meanwhile LOD and LOQ were 1.653 mg/L and 5.508 mg/L. Based on the results can be concluded that the method analysis of P2O5 using spectrophotometry UV-Visible expressed good validity and can be applied as routine method at laboratory.
关键词： UV-Visible spectrophotometry,inorganic fertilizer,phosphorus,validation,P2O5
更新于2025-09-09 09:28:46
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A green approach for the quantification of daptomycin in pharmaceutical formulation by UV spectrophotometry
摘要： Daptomycin is the first approved drug from a new class of antimicrobials, the cyclic lipopeptides, and is a very important antimicrobial agent in current clinical practice. Currently, there are no “green” analytical methods described in the literature to analyze the typical pharmaceutical dosage form of daptomycin. Thus, the aim of this work was to validate an environment-friendly spectrophotometric method in the UV region, for the analysis of daptomycin as a lyophilized powder. Water was used as diluent and the analyses were carried out on a spectrophotometer at 221 nm. The method met all validation requirements of the ICH guidelines, over a concentration range of 6-21 μg mL-1. A Student’s t-test demonstrated that the proposed method was comparable to an HPLC method previously validated. Thus, the validated spectrophotometric method could quantify daptomycin in a powder form for injectable solutions, while being an economical, rapid, and “green” alternative for routine analysis in quality control.
关键词： Antimicrobials/quality control,Daptomycin/determination,Spectrophotometry/green analytical method,Spectrophotometry/UV region/quantitative analysis
更新于2025-09-04 15:30:14
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Preparation of water-soluble asphalt carbon dots and hyperchromic effect to Cr (VI)
摘要： Water-soluble asphalt carbon dots（W-CDs）was prepared from medium - temperature coal tar pitch as raw material, via mixed acid oxidation，alkali solubilization and acid precipitation method. It was observed that as-prepared W-CDs were irregular particles with good water dispersibility and the particle size was controlled by the pH of the acid precipitation solution by a polarizing microscope . Infrared spectroscopy confirmed that the surface of the W-CDs was functionalized by hydrophilic and color-promoting functional groups, which had good water solubility; the thermal weight loss proved to be good thermal stability below 200°C; the fluorescence spectrum proved that the fluorescence emission peak position of the carbon dots appears red shift with increase of excitation wavelength, with fluorescence conversion property, and its emission light intensity decreases, belonging to non-resonant fluorescence type of direct jump fluorescence; UV spectrum proves that the addition of W-CDs can be chromium (VI) CrO4 2- content The detection limit was increased from milligram to microgram; the molar absorptivity of CrO4 2- was increased by 4 times. The experimentally optimized W-CDs-ultraviolet-viscometry method for measuring CrO4 2- conditions: W-CDs to chromium ratio of 8:2, pH of 8, hexamethylenetetramine as a surfactant, and the solution was allowed to stand at room temperature for 45 min.
关键词： hyperchromic effect,Cr (Ⅵ),UV-vis spectrophotometry,Water-soluble asphalt carbon dots
更新于2025-09-04 15:30:14
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Spectrofluorimetric and Spectrophotometric Determination of Troxerutin in Pharmaceutical Preparations
摘要： Two new, sensitive and simple spectrofluorimetric and spectrophotometric methods have been developed for the determination of troxerutin in pharmaceutical preparations. Troxerutin inhibits the activity of hemoglobin on the catalyzed reaction of H2O2 with rhodamine B, which is a highly sensitive fluorogenic and chromogenic reagent used in many investigations. The reaction product was measured by spectrofluorimetry at 575 nm after excitation at 550 nm. The percentage inhibition was directly proportional to the concentration over the range 0.04-1.5 μg/mL for the spectrofluorimetric method. The relation between the percentage inhibition of the absorbance at 550 nm and the concentration is rectilinear over the range 0.2-30 μg/mL. This method was applied successfully to the determination of troxerutin in pharmaceutical dosage form.
关键词： Spectrophotometry,Troxerutin,Spectrofluorimetry
更新于2025-09-04 15:30:14
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Development and Validation of Cost Effective UV-Spectrophotometric Method for Estimation of Domperidone in Bulk and Pharmaceutical Formulations
摘要： Simple and cost effective UV-spectrophotometric method was developed for the estimation of domperidone in bulk and pharmaceutical formulations. Domperidone was analyzed at 284 nm in 100 mM hydrochloric acid (pH 1.2). Apparent molar absorptivity and Sandell’s sensitivity were found to be 1.27 × 104 L mol-1 cm-1 and 0.034336 μg cm-2/0.001A, respectively which infer good sensitivity of the method. The method demonstrated linearity in concentration range of 5-35 μg mL-1 (regression equation: absorbance = 0.0289 × concentration in μg mL-1 + 0.0077; R2 = 1) in selected media. Method was fully validated for selectivity, accuracy, precision, robustness as per ICH guidelines. The detection and quantification limits were found to be 0.398 and 1.121 μg mL-1, respectively. The results of various validation parameters confirmed that the proposed method is accurate, selective and precise (relative standard deviation < 2 %), while being simple and cost effective. This method was found suitable for qualitative and quantitative estimation of domperidone in bulk and different formulation.
关键词： Domperidone,UV-spectrophotometry
更新于2025-09-04 15:30:14
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A Passive Microfluidic Device Based on Crossflow Filtration for Cell Separation Measurements: A Spectrophotometric Characterization
摘要： Micro?uidic devices have been widely used as a valuable research tool for diagnostic applications. Particularly, they have been related to the successful detection of different diseases and conditions by assessing the mechanical properties of red blood cells (RBCs). Detecting deformability changes in the cells and being able to separate those cells may be a key factor in assuring the success of detection of some blood diseases with diagnostic devices. To detect and separate the chemically modi?ed RBCs (mimicking disease-infected RBCs) from healthy RBCs, the present work proposes a micro?uidic device comprising a sequence of pillars with different gaps and nine different outlets used to evaluate the ef?ciency of the device by measuring the optical absorption of the collected samples. This latter measurement technique was tested to distinguish between healthy RBCs and RBCs chemically modi?ed with glutaraldehyde. The present study indicates that it was possible to detect a slight differences between the samples using an optical absorption spectrophotometric setup. Hence, the proposed micro?uidic device has the potential to perform in one single step a partial passive separation of RBCs based on their deformability.
关键词： red blood cells,separation,micro?uidics,cross-?ow ?ltration,spectrophotometry
更新于2025-09-04 15:30:14
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Development and validation of a simple spectrophotometric method for the determination of methyldopa in both bulk and marketed dosage formulations
摘要： A simple, precise, sensitive, rapid, specific and economical spectrophotometric method was developed to determine methyldopa (MTD) content in bulk and pharmaceutical dosage formulations. The proposed method was based on the formation of a colored product from the nitrosation reaction of MTD with sodium nitrite in an acid medium. The resultant nitroso derivative species reacts further with sodium hydroxide and is converted it into a more stable compound. This yellow nitrosation product exhibited an absorption maximum at 430 nm. Beer’s Law was obeyed in a concentration range of 6.37 to 82.81 mg mL-1 MTD with an excellent coefficient of determination (R2 = 0.9998). No interference was observed from common excipients in formulations. The results showed the method to be simple, accurate and readily applied for the determination of MTD in pure form and in pharmaceutical preparations. The analytical results obtained for these products using the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at a 95% confidence level.
关键词： Pharmaceutical formulations/quality control,Spectrophotometry/qualitative analysis,Methyldopa/spectrophotometric determination
更新于2025-09-04 15:30:14
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Spectrophotometic Determination of Trace Zinc in Milk Powder by Ethyl Rhodamine B
摘要： In the presence of the surfactant gum Arabic, the Zn(II)-SCN–-ERB (ERB = ethyl rhodamine-B) ternary chromogenic reaction system was studied. The results showed that, in the acetic acid-sodium acetate medium of pH 5.0, Zn(II)-SCN–-ERB forms a rose red complex of 1:4:2 at room temperature. The complex has a maximum absorption wavelength of 625 nm, a zinc content of 0.16-8.00 μg/25 mL conforming to the Lambert-Beer’s law, a molar absorption coefficient ε625 of 1.02 × 105 L mol-1 cm-1 and a detection limit of 0.045 μg/25 mL. Using this method to determine the trace zinc in milk powder, the relative standard deviation is less than 2 % and the results are satisfactory.
关键词： Spectrophotometry,Ethyl rhodamine B,Zinc(II),Potassium thiocyanate
更新于2025-09-04 15:30:14
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Detection in UV-visible spectrophotometry: Detectors, detection systems, and detection strategies
摘要： A compilation of the new developments in terms of detection, detections systems and detection strategies in Ultraviolet-Visible (UV-Vis) spectrophotometry is presented and discussed. It is shown that this evolution has promoted the use of UV-Vis spectrophotometry as a simple, sensitive, reliable, and low cost technique, that allows the determination of very low concentrations of compounds, and the use of very small amounts of samples. The versatility, and the portability of the developed equipment and strategies, have also contributed for the continuous use of UV-Vis spectrophotometry, over the years. By the examples of its use in diverse fields such as agriculture, food, clinical, pharmaceutical, and environmental is highly expectable that detection in UV-Vis spectrophotometry, continues to evolve and to promote this kind of applications.
关键词： Organic compounds,Quantitative analysis,Detectors,Qualitative analysis,UV-vis spectrophotometry,Detection
更新于2025-09-04 15:30:14