scholarly journals Software-guided microscale flow calorimeter for efficient acquisition of thermokinetic data

2021 ◽  
Author(s):  
Timothy Aljoscha Frede ◽  
Marlene Dietz ◽  
Norbert Kockmann
Keyword(s):  
Design Of Experiments ◽  
Process Development ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Flow Calorimeter ◽  
Microscale Flow ◽  
Increased Sensitivity ◽  
Important Time ◽  
Optimal Reaction

AbstractFast chemical process development is inevitably linked to an optimized determination of thermokinetic data of chemical reactions. A miniaturized flow calorimeter enables increased sensitivity when examining small amounts of reactants in a short time compared to traditional batch equipment. Therefore, a methodology to determine optimal reaction conditions for calorimetric measurement experiments was developed and is presented in this contribution. Within the methodology, short-cut calculations are supplemented by computational fluid dynamics (CFD) simulations for a better representation of the hydrodynamics within the microreactor. This approach leads to the effective design of experiments. Unfavourable experimental conditions for kinetics experiments are determined in advance and therefore, need not to be considered during design of experiments. The methodology is tested for an instantaneous acid-base reaction. Good agreement of simulations was obtained with experimental data. Thus, the prediction of the hydrodynamics is enabled and the first steps towards a digital twin of the calorimeter are performed. The flow rates proposed by the methodology are tested for the determination of reaction enthalpy and showed that reasonable experimental settings resulted. Graphical abstract A methodology is suggested to evaluate optimal reaction conditions for efficientacquisition of kinetic data. The experimental design space is limited by thestepwise determination of important time scales based on specified input data.

Optimizing determination of plasma albumin by the bromcresol green dye-binding method.

1981 ◽  
Vol 27 (1) ◽  
pp. 144-146 ◽  
Author(s):  
W S Robertson
Keyword(s):  
Reaction Time ◽  
Linear Regression ◽  
Human Plasma ◽  
Protein Composition ◽  
Improved Method ◽  
Reaction Conditions ◽  
Plasma Albumin ◽  
Optimal Reaction ◽  
Bromcresol Green

Abstract Some modifications of the conditions of the reaction between plasma and bromcresol green have led to an improved method for determination of plasma albumin with the Vickers M300 multichannel analyzer. Dye concentration and reaction time are the factors principally influencing method specificity, but variable protein composition of human plasma also affects it, so that optimal reaction conditions vary from specimen to specimen. Thus a compromise must be reached such that the best conditions for determining plasma albumin over a range of different protein concentrations are achieved. In the proposed method for the Vickers M300 a reaction time of 12 s (the minimum possible) is used. Comparison with "rocket" immunoelectrophoresis gave the following linear regression: y = 10 + 0.79 x (n = 91; r = 0.96).

scholarly journals Process Development and Synthesis of Process-Related Impurities of an Efficient Scale-Up Preparation of 5,2′-Dibromo-2,4′,5′-Trihydroxy Diphenylmethanone as a New Acute Pyelonephritis Candidate Drug

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 468
Author(s):  
Xiu E Feng ◽  
Ke Meng Cui ◽  
Qing Shan Li ◽  
Zi Cheng Wu ◽  
Fei Lei
Keyword(s):  
Acute Pyelonephritis ◽  
High Performance ◽  
Process Development ◽  
Scale Up ◽  
Preparation Process ◽  
Reaction Conditions ◽  
Related Impurities ◽  
Candidate Drug ◽  
Optimal Reaction ◽  
Impurity Profiles

Based on a foregoing gram-scale laboratory process, an efficient scale-up preparation process of 5,2′-dibromo-2,4′,5′-trihydroxydiphenylmethanone (LM49-API), a new acute pyelonephritis candidate drug, was developed and validated aiming to reduce by-products and achieve better impurity profiles. Meanwhile, the polymorph of LM49-API and process-related impurities were also investigated. Ultimately, the optimal reaction conditions were verified by evaluating the impurity profiles and their formation during the synthesis. Six process-related impurities were synthesized and identified, being useful for the quality control of LM49-API. Its finalized preparation process was further validated at 329–410 g scale-up production in 53.4–57.1% overall yield with 99.95–99.98% high-performance liquid chromatography (HPLC) purity, and it is currently viable for commercial production. LM49-API-imC and LM49-API-imX were identified as the main single impurities in LM49-API, with the content controlled to be less than 0.03%.

CHROMOGENIC ENDOTOXIN ASSAYS. - FURTHER METHOD DEVELOPMENT AND PRACTICAL EXPERIENCE

1987 ◽  
Author(s):  
K Nilsson ◽  
P Friberqer
Keyword(s):  
Method Development ◽  
Practical Experience ◽  
Reaction Conditions ◽  
Laboratory Equipment ◽  
Reagent Cost ◽  
Considerable Work ◽  
Almost All ◽  
Optimal Reaction ◽  
Quantitative Procedure

A kit for the determination of endotoxin by using Lumulus lysate (LAL) and a chromogenic substrate has now been available for three years. Here we will summarize the present status concerning its usefulness in the control of parenteral drugs, in hygienic control and in clinical diagnosis.The wide variation of uses, demands considerable work for method adaptation to the various types of specimen and laboratory. Almost all samples have to be pretreated to become compatible with the reagents in the assay. It has also been found to be important to consider variousdemands depending on the number of samples, how fast the answer is wanted, simplicity and accuracy of the assay that is needed as well as equipment available. In some cases a single screening test is required. Then a tube with 100 pi of LAL reagent can be taken from the freezer. The other extreme is the determination of hundreds of samples in each series. Then microplates and suitable readers can be of great help. Several other procedures used on special occasions allowing e.g. wide assay range or low reagent cost will also be presented.Manual and microplate procedures have been found suitable and can be made safe regarding contamination and losses of endotoxin. Single stage and micro methods have been tested and found to work. Data concerning material and laboratory equipment have been collected and are now available.By using a quantitative procedure forthe determination of the small amounts of endotoxin present in most samples, it has been possible to find optimal reaction conditions and to trace various kindsof errors. Procedures for method controland trouble shooting are also suggested.

scholarly journals Fluorometric Detection of Thiamine Based on Hemoglobin–Cu3(PO4)2 Nanoflowers (NFs) with Peroxidase Mimetic Activity

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6359
Author(s):  
Hangjin Zou ◽  
Yang Zhang ◽  
Chuhan Zhang ◽  
Rongtian Sheng ◽  
Xinming Zhang ◽  
...  
Keyword(s):  
Food Production ◽  
Limit Of Detection ◽  
Vitamin B1 ◽  
Tween 80 ◽  
Fluorometric Detection ◽  
Oh Radicals ◽  
Fluorometric Method ◽  
Reaction Conditions ◽  
Optimal Reaction

Component analysis plays an important role in food production, pharmaceutics and agriculture. Nanozymes have attracted wide attention in analytical applications for their enzyme-like properties. In this work, a fluorometric method is described for the determination of thiamine (TH) (vitamin B1) based on hemoglobin–Cu3(PO4)2 nanoflowers (Hb–Cu3(PO4)2 NFs) with peroxidase-like properties. The Hb–Cu3(PO4)2 NFs catalyzed the decomposition of H2O2 into ·OH radicals in an alkaline solution that could efficiently react with nonfluorescent thiamine to fluoresce thiochrome. The fluorescence of thiochrome was further enhanced with a nonionic surfactant, Tween 80. Under optimal reaction conditions, the linear range for thiamine was from 5 × 10−8 to 5 × 10−5 mol/L. The correlation coefficient for the calibration curve and the limit of detection (LOD) were 0.9972 and 4.8 × 10−8 mol/L, respectively. The other vitamins did not bring about any obvious changes in fluorescence. The developed method based on hybrid nanoflowers is specific, pragmatically simple and sensitive, and has potential for application in thiamine detection.

scholarly journals Online Preconcentration and Determination of Trace Amounts of Zinc in Nature Waters

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Liang Wei ◽  
Xinshen Zhang ◽  
Yichun Dai ◽  
Jin Huang ◽  
Yong-hong Xie ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Tween 80 ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Buffer Solutions ◽  
Relative Standard ◽  
On Line ◽  
Standard Solution ◽  
Zinc Determination

A simple, sensitive, reliable and flexible flow injection spectrophotometric method is proposed for on-line preconcentration and determination of trace amounts of zinc in water. At the presence of Tween-80 in pH 9.3 buffer solutions, the shade of color of Zn (II)-PAN complex is in a linear relation to the zinc amount at the point of the maximum absorption peak of 560 nm. The optimal experimental conditions, including reaction conditions and preconcentration conditions, had been obtained. The linear range of the proposed method was between 2.0 and 360 μg L−1and the detection limit was 0.42 μg L−1. The relative standard deviation was 3.55% and 2.14% for 5.0 μg L−1and 50 μg L−1of zinc standard solution (n=8). The method had been successfully applied to zinc determination in water samples and the analytical results were satisfactory.

Bayesian based reaction optimization for complex continuous gas-liquid-solid reactions

2021 ◽  
Author(s):  
Runzhe Liang ◽  
Xiaonan Duan ◽  
Jisong Zhang ◽  
Zhihong Yuan
Keyword(s):  
Optimization Algorithms ◽  
Reaction Conditions ◽  
Reaction Optimization ◽  
Optimal Reaction

In recent years, self-optimization strageties have been gradually utilized for the determination of optimal reaction conditions owing to their high convenience and independence of researchers’ experiences. However, most self-optimization algorithms...

Studies on the Synthetic Process of 4,5-Dicyano Dimethyl Phthalate

2014 ◽  
Vol 1053 ◽  
pp. 252-256 ◽  
Author(s):  
Fei Zhang ◽  
Shi Rong Wang ◽  
Xiang Gao Li ◽  
Yin Xiao ◽  
Lu Jin Pan
Keyword(s):  
Thionyl Chloride ◽  
High Purity ◽  
Molar Ratio ◽  
Process Conditions ◽  
Dimethyl Phthalate ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Synthetic Process ◽  
Cuprous Cyanide ◽  
Optimal Reaction

4, 5-dicyano dimethyl phthalate was an intermediate of the synthesis of phthalocyanine compounds substituted carboxyl. Under the existence of the solvent methanol, 4, 5-dibromo dimethyl phthalate was synthesized by 4,5-Dibromophthalic acid and thionyl chloride.Then it was with cuprous cyanide to get 4,5-dicyano dimethyl phthalate. By studying the process conditions, we got the optimal reaction conditions of 4,5-Dibromo dimethyl phthalate which was thionyl chloride: 4,5-Dibromophthalic acid (2.5:1.0 , molar ratio) and by enlarging 10 times of the experimental conditions, we got the yield 86.4% which was higher than the reported 66.8%.And the optimal reaction conditions of 4,5-dicyano dimethyl phthalate was that high purity argon, absolutely anhydrous DMF, cuprous cyanide and 4,5-Dibromo dimethyl phthalate whose molar ratio were 4.0:1.0. By enlarging 10 times of the experimental conditions, we got the yield 19.0%.

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