Víctor Cerdà

Bio: Víctor Cerdà is an academic researcher from University of the Balearic Islands. The author has contributed to research in topics: Flow injection analysis & Detection limit. The author has an hindex of 44, co-authored 478 publications receiving 9829 citations. Previous affiliations of Víctor Cerdà include University of Barcelona & Technical University of Berlin.

Solid-phase extraction of organic compounds: A critical review (Part I)

Abstract: Solid-phase extraction (SPE) is the most widely used method for the extraction, changing of solvents, cleanup, concentration, and fractionation of organic compounds from a number of samples. This procedure is also very useful for desalting proteins and sugar samples. However, most SPE procedures are still poorly developed, with little consideration to the physics involved in the process and are described as largely empirical, labor-intensive, and time-consuming trial-and-error processes, without much systematization. The objective of this study is to propose a number of contradictions, disagreements, failings, and shortcomings of the SPE procedures found elsewhere. The different arguments introduced in this study attempt to challenge the suitability of this procedure, particularly when it is conducted in the traditional manner (under gravity and at a high flow rate). The first part of this study focuses on describing the state-of-the-art in SPE and its physical fundamentals.

Magnetic solid-phase extraction using metal-organic frameworks (MOFs) and their derived carbons

Abstract: Magnetic solid-phase extraction (MSPE) is a useful sample preparation technique, enabling the dispersion of solid sorbents in liquid sample matrices followed by the magnetic retrieval of the sorbent. MSPE can be implemented using any kind of magnetic materials independently of their size and shape, and is a powerful tool for the application of micro/nanomaterials for analytical sample preparation. Metal-organic frameworks (MOFs) have emerged recently as highly valuable sorbents for solid-phase extraction (SPE) due to their large surface area, chemical selectivity, and versatility for tuning their chemical composition and pore size. For MSPE applications, MOFs can be magnetized, or used as precursors for the preparation of MOF-derived magnetic porous carbons (MPCs). In this review, we outline and discuss the different approaches for the preparation of magnetic MOFs and their conversion to MPCs. The applications of magnetic MOFs and MPCs as sorbents for MSPE are critically discussed and oriented to the type of MOF used and the extracted analytes. Recent efforts on the automation of MSPE procedures using magnetic MOFs and MPCs are also described.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent

Abstract: Publisher Summary This chapter discusses the analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Analyses of the Folin-Ciocalteu (FC) type are convenient, simple, and require only common equipment and have produced a large body of comparable data. Under proper conditions, the assay is inclusive of monophenols and gives predictable reactions with the types of phenols found in nature. Because different phenols react to different degrees, expression of the results as a single number—such as milligrams per liter gallic acid equivalence—is necessarily arbitrary. Because the reaction is independent, quantitative, and predictable, analysis of a mixture of phenols can be recalculated in terms of any other standard. The assay measures all compounds readily oxidizable under the reaction conditions and its very inclusiveness allows certain substances to also react that are either not phenols or seldom thought of as phenols (e.g., proteins). Judicious use of the assay—with consideration of potential interferences in particular samples and prior study if necessary—can lead to very informative results. Aggregate analysis of this type is an important supplement to and often more informative than reems of data difficult to summarize from various techniques, such as high-performance liquid chromatography (HPLC) that separate a large number of individual compounds .The predictable reaction of components in a mixture makes it possible to determine a single reactant by other means and to calculate its contribution to the total FC phenol content. Relative insensitivity of the FC analysis to many adsorbents and precipitants makes differential assay—before and after several different treatments—informative.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Genesis and development of DPPH method of antioxidant assay

Abstract: α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method offers the first approach for evaluating the antioxidant potential of a compound, an extract or other biological sources. This is the simplest method, wherein the prospective compound or extract is mixed with DPPH solution and absorbance is recorded after a defined period. However, with the advancement and sophistication in instrumental techniques, the method has undergone various modifications to suit the requirements, even though the basic approach remains same in all of them. This article presents a critical review on various developments to the DPPH method.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Abstract: Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.