NMR spectroscopy with compact instruments Singh, Kawarpal; Blümich, Bernhard
TrAC, Trends in analytical chemistry (Regular ed.),
October 2016, 2016-10-00, Volume:
83
Journal Article
Peer reviewed
•Compact NMR spectroscopy.•Multi-nuclear NMR.•Product and quality control.•NMR reaction monitoring.•Two-dimensional NMR.
NMR spectroscopy with compact instruments opens new perspectives for the use ...of NMR. While the field strength of compact instruments is low, they potentially match today's high-field instruments in methodical diversity, although by default they are operated in non-expert mode with a mouse click. Because size and price are low, they open new opportunities for the use of NMR spectroscopy. One is product and quality control and another is real-time reaction monitoring in the academic and industrial research laboratory on the workbench by observing nuclei such as 1H, 13C, 31P, 19F, 7Li and 11B. With compact NMR spectrometers, not only standard one-dimensional experiments can be executed to retrieve chemical information but also the two-dimensional experiments such as HSQC, HMBC, HETCOR and COSY. The state of the art and progress in compact NMR spectroscopy is reviewed concerning 1D and 2D spectroscopy along with their use in product control and reaction monitoring.
Polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid are essential fatty acids for humans. PUFAs are biosynthesized by either ...desaturases/elongases from oleic acid or PUFA synthases from acetyl units. PUFA synthases are composed of three or four subunits, and each creates a specific PUFA even though the multiple catalytic domains in each subunit are very similar. We recently dissected these PUFA synthases by in vivo and in vitro experiments and elucidated how the enzymes control PUFA profiles. Moreover, for the first time, we converted a practical microalgal docosahexaenoic acid synthase into an eicosapentaenoic acid synthase based on the results.
Based on the composition characteristics of carbide slag and the application of polyvinyl chloride, a method of preparing calcium carbonate with microstructure and nanostructure by using carbide slag ...as a raw material and ammonium chloride as a leaching agent was proposed. The factors for the preparation of calcium carbonate and the effects of different conditions on the crystal phase, grain size, and morphology of calcium carbonate were systematically studied. The results showed that the nanosized calcium carbonate was prepared at 60 mL/min, 25 °C, no additional ammonia, and 60 min. The product of spherical vaterite was in accordance with the relevant standards for the industrial precipitation of calcium carbonate. Moreover, the reuse of carbonation filtrate was realized. The crystal phase, grain size, and morphology of the carbonation product could be controlled by adjusting the reaction conditions. The manuscript provided a new idea for resource utilization of carbide slag and preparing nanocalcium carbonate.
Display omitted
•High purity CaCO3 with different grain sizes, structures, and morphologies is successfully produced.•NH4Cl is used to leach Ca2+ from carbide slag and can be recycled.•The crystal phase, grain size, and morphology of CaCO3 could be controlled by adjusting the reaction conditions.
The wetting behavior and the interfacial reactions of molten Ti-40Ni-20Nb (at.%) filler alloy on the BN-SiO2 ceramic were investigated by the a sessile drop method at 1453 K under a vacuum ...atmosphere. Results demonstrated that a good wettability with final contact angles of approximately 44°–15° was obtained. Interfacial microstructure examinations revealed that the Ti-40Ni-20Nb filler alloy reacted with the BN-SiO2 ceramic, which resulted in the formation of TiN, TiB, Ti5Si3 and Ti3O5 at the interface. The wetting process of the Ti-40Ni-20Nb filler alloy on the BN-SiO2 ceramic was identified into 3 stages: (i) rapid decreasing stage, (ii) sluggish spreading stage and (iii) final equilibrium stage. In order to reveal the essence of the reactive wetting, the wettability of the Ti-40Ni-20Nb (at.%) filler alloy on the BN-SiO2 ceramic with three different BN contents were investigated. For the Ti-40Ni-20Nb/BN-SiO2 system, the wettability mainly depended on the final interfacial chemistry of the system but the intensity of the interfacial reactions. The final contact angle of the Ti-40Ni-20Nb filler alloy on the BN-SiO2 ceramic decreased as the BN content in the ceramic was increased from 20% to 80%.
Display omitted
•Reaction layer mainly composed by TiN, TiB, Ti5Si3 and Ti3O5 is formed adjacent to the BN-SiO2 ceramic.•The wetting of the TiNiNb filler alloy/BN-SiO2 ceramic system can be explained by “Reaction Product Control” model.•With the improving of the BN content in the BN-SiO2 ceramic, the ratio of (TiN+TiB):(Ti5Si3+Ti3O5) in the reaction products increases, which can improve the wetting of the BN-SiO2 ceramic. With BN content increases from 20% to 80%, the final contact angle decreases from 44° to 15°.
The development of a thermogravimetry coupled to an atmospheric pressure photoionization mass spectrometry (TG-APPI-MS) with a high temperature and flexible transfer line is presented. A method was ...developed to analyze plasticizers in solution which consist of a solvent evaporation step and subsequent evaporation of the analyte. These solutions of dibutyl phthalate (DBP) in hexane were used to investigate the repeatability (RSD: 3.6%) and linearity (R2: 0.9995) of the new developed system. With the new device the detection of different phthalates in a standardized PVC (polyvinyl chloride) polymer is shown. On the example of ASA, the degradation of a pharmaceutical drug is investigated. The dimerization and the possible trimerization of ASA during the thermal degradation is shown. Ten tablets of different ASA manufacturers were analyzed with the new developed analysis platform. The active substance was found in every tablet. Differences in mass spectral data as well as the studying of the pack insert were used to assign the tablets to companies and their subsidiaries. A unique formulation of ASA was found to have a different mass pattern when analyzed with TG-APPI-qMS. The developed device is a promising tool for the product control and the identification of falsified drugs.
Display omitted
•Development of a TG-APPI-MS coupling.•Analysis of plasticizers in polymers.•Degradation mechanisms of drugs can be investigated by TG-APPI-MS.
ε‐Caprolactone is an important non‐toxic compound for polymer synthesis like polycaprolactone which has been widely used in drug delivery and degradable plastics. To meet the demand for a green ...economy, a bi‐enzymatic cascade, consisting of an alcohol dehydrogenase (ADH) and a cyclohexanone monooxygenase (CHMO), was designed and introduced into Escherichia coli to synthesize ε‐caprolactone from cyclohexanol with a self‐sufficient NADPH‐cofactor regeneration system. To further improve the catalytic efficiency, a carbonyl group‐dependent colorimetric method using inexpensive 2,4‐dinitrophenylhydrazine (DNPH) was developed for assay of cyclohexanone, an intermediate production of cascade reaction. It can be used to screen mutant strains with high catalytic efficiency from high‐throughput library by detecting the absorbance value in microtiter plates (MTP) instead of gas chromatography (GC) analysis. Moreover, an RBS combinatorial library was constructed for balancing the expression of ADH and CHMO from two independent transcriptional units. After the high‐throughput screening based on intermediate product control, an optimal variant with higher substrate tolerance and long‐term stability was obtained from RBS combinatorial library. Through a fed‐batch process, ε‐caprolactone production reached 148.2 mM after 70 h of reaction under the optimized conditions, which was the highest yield achieved to date.
Graphical and Lay Summary
ε‐Caprolactone is an organic chemical compound, which is mostly used as a monomer to synthesize valuable biodegradable polymer in composite materials and drug delivery. A bi‐enzyme cascade reaction was constructed in Escherichia coli to synthesize ε‐caprolactone from cyclohexanol. An RBS combinatorial library was constructed to regulate the ratio of ADH and CHMO simultaneously. Meanwhile, a high‐throughput DNPH screening method was established to screen high‐performance strains efficiently and conveniently. This work provides a good reference for other in vivo artificial cascade reactions.
The processes for manufacturing and operating modern technical products require expertise in multiple disciplines like mechanical engineering, electrical engineering, and software engineering. ...Assessing the current condition and quality of these processes and the machines involved is challenging due to the inherent complexity of the products and the required expertise in multiple engineering domains. Globalization and increasing competition make it necessary to reduce production costs while at the same time ensuring high throughput and product quality. Without the ability to precisely assess the condition and quality of production processes and involved machines, taking action to steer these metrics is nearly impossible and results in unnecessary high production costs. In our previous publications, we introduced the concept of Key Performance Indicators (KPIs) for mechatronic systems as a concept to assess the condition and quality of products and production processes in a graspable yet substantial and efficient way.
In this paper, we further refine our KPI concepts und evaluate them for two different use cases: we apply our KPI concept to a manufacturing process in the mechatronic system domain and an operation process in the food production domain. We provide detailed insights in how we applied our concepts within these domains and report about lessons learned. In addition, we provide a business case estimation for our software solution that assesses the KPIs of our food production domain example.
•Concept and Structure of Key Performance Indicators (KPIs) for mechatronic systems.•Procedure for identification and specification of production process-specific KPIs.•Cost-efficient monitoring and control of production process using KPIs.•Successful implementation for ATM manufacturing process at Diebold Nixdorf.•Successful implementation for food production process in cooperation with GEA.
Recently, several health authorities have requested substantial detail from sponsor firms regarding the practices employed to generate the production cell line for recombinant DNA-(rDNA) derived ...biopharmaceuticals. Two possible inferences from these regulatory agency questions are that (1) assurance of “clonality” of the production cell line is of major importance to assessing the safety and efficacy of the product and (2), without adequate proof of “clonality”, additional studies of the cell line and product are often required to further ensure the product's purity and homogeneity. Here we address the topic of “clonality” in the broader context of product quality assurance by current technologies and practices, as well as discuss some of the relevant science and historical perspective. We agree that the clonal derivation of a production cell line is one factor with potential impact, but it is only one of many factors. Further, we believe that regulatory emphasis should be primarily placed on ensuring product quality of the material actually administered to patients, and on ensuring process consistency and implementing appropriate control strategies through the life cycle of the products.
The purpose of this paper is to present progress made since 1998 in understanding and modeling reactive wetting in metal/ceramic systems. The paper focuses on the two published analyses of reactive ...wetting leading to very different descriptions of both thermodynamics and kinetics of this phenomenon: the analysis proposed by author’s group and the analysis presented by Saiz et al.
Aromatic amino acid homeostasis was investigated in cell suspension cultures of
and was related to the activity of the first enzyme in aromatic biosynthesis, 3-deoxy-D-
-heptulosonate-7-phosphate ...(DAHP) synthase. An inverse relationship was found between the intracellular content of free phenylalanine, tyrosine and tryptophan and enzyme specific activity levels, suggesting the occurrence of end-product control mechanisms. Two DAHP synthase isogenes are present in wild tobacco that showed a different expression pattern during the culture growth cycle. Intracellular levels of aromatic amino acids were increased or decreased by adding the culture medium with phenylalanine, tyrosine and tryptophan, or with sublethal doses of the shikimate pathway inhibitor glyphosate, respectively. As a consequence, enzyme levels varied in the opposite direction. The concomitant exogenous supply of glutamine further reduced enzyme activity in mid-log cells, suggesting induction by both aromatic amino acid depletion and nitrogen starvation.
