IUPAC definitions

The IUPAC definition of pH39 is based upon a 0.05M solution of potassium hydrogenphthalate as the reference value pH standard (RVS). In addition, six further primary standard solutions are also defined which between them cover a range of pH values lying between 3.5 and 10.3 at room temperature, and these are further supplemented by a number of operational standard solutions which extend the pH range covered to 1.5-12.6 at room temperature. The composition of the RVS solution, of three of the primary standard solutions and of two of the operational standard solutions is detailed below, and their pH values at various temperatures are given in Table 15.4. It should be noted that the concentrations are expressed on a molal basis, i.e. moles of solute per kilogram of solution. 

Long GL, Winefordner JD (1983) Limit of detection. A closer look at the IUPAC Definition. Anal Chem 55 712A... 

The majority of the names for chemicals in this alphabetically arranged index conform to one of the systematic series permitted under various sections of the IUPAC Definitive Rules for Nomenclature. Where there is a marked difference between these names and the alternative names recommended in the IUPAC-based BS2472 1983 or ASE 1985 nomenclature lists, or long established traditional names, these are given as synonyms in parentheses after the main title. These synonyms also have their own index entry, cross-referenced back to the IUPAC-based names used as bold titles in the text of Volume 1. 

Long, G L and Winefordner, J D (1983), Limit of detection—A closer look at the IUPAC definition. Analytical Chemistry, 55, 712A-24A. 

The principal advances in the systematization of organic nomenclature have come from the International Union of Pure and Applied Chemistry (IUPAC) Commission on the Nomenclature of Organic Chemistry, and from the Chemical Abstracts Service. The IUPAC Definitive Rules for Hydrocarbons and Heterocyclic Systems (1957)4 and for Characteristic Groups (1965)5 have been widely accepted by the chemical community, and, in their latest revised form,6 constitute the standard reference work. These rules are closely related to those developed in parallel by Chemical Abstracts for indexing purposes, and it is fortunate that, as a result of close cooperation between the two bodies, there are few areas of disagreement. 

The IUPAC Definitive Rules for Nomenclature of Steroids15 contain proposals for naming steroid alkaloids and steroids containing fused... 

The following extracts from the 1969 IUPAC Definitive Rules for the Nomenclature of Organic Chemistry, Sections A-C,6 are reproduced by permission of the IUPAC authorities. 

The traditional view of emulsion stability (1,2) was concerned with systems of two isotropic, Newtonian liquids of which one is dispersed in the other in the form of spherical droplets. The stabilization of such a system was achieved by adsorbed amphiphiles, which modify interfacial properties and to some extent the colloidal forces across a thin liquid film, after the hydrodynamic conditions of the latter had been taken into consideration. However, a laige number of emulsions, in fact, contain more than two phases. The importance of the third phase was recognized early (3) and the IUPAC definition of an emulsion included a third phase (4). With this relation in mind, this article deals with two-phase emulsions as an introduction. These systems are useful in discussing the details of formation and destabilization, because of their relative simplicity. The subsequent treatment focuses on three-phase emulsions, outlining three special cases. The presence of the third phase is shown in order to monitor the properties of the emulsion in a significant manner. 

Even a cursory perusal of any analytical journal must lead one to the conclusion that trace and ultratrace analyses is a domain of chemical analysis that is gaining in importance. This conclusion is corroborated not only by the feelings and opinions of analysts. According to the current IUPAC definition of the term trace component, the limit from which we can talk about trace analysis is the concentration of 100 ppm (100 pg g ) Naturally, this limit is purely conventional and is not constant. As recently as 30 years ago, trace analysis was understood to denote activities aiming to determine components at a concentration level one order of magnitude higher, that is, below 1000 ppm, or 0.1%. 

According to the IUPAC definition, porous materials ate divided into three different classes, depending on their pore sizes. Mesoporous materials are described as materials whose pore diameters lie in the range between 2 and 50 nm. Solids with a pore diameter below 2 nm or above 50 nm belong to the class of micro- and macroporous materials, respectively. 

According to IUPAC definitions, three groups of pores are distinguished ... 

The IUPAC definition understandably states that reversed phase chromatography is an elution procedure in which the mobile phase is significantly more polar than the stationary phase . This is a somewhat simplistic statement that covers a wealth of... 

Panderi and Parissi-Poulou developed a microbore liquid chromatographic method for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms [30]. The use of a BDS C-18 microbore analytical column was found to result in substantial reduction in solvent consumption and in increased sensitivity. The mobile phase consisted of a mixture of 25 mM sodium dihydrogen phosphate buffer (pH 4.8) and acetonitrile (11 9 v/v), pumped at a flow rate of 0.4 mL/min. Detection was effected at 250 nm using an ultraviolet absorbance detector. The intra- and inter-day relative standard deviation values were less than 1.25% (n = 5), while the relative percentage error was less than 0.9% (n = 5). The detection limits obtained according to the IUPAC definition were 0.88 and 0.58 pg/mL for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied to the quality control of commercial tablets and content uniformity test, and proved to be suitable for rapid and reliable analysis. 

LoDs shown in Table 6.7 were compared with those of Table 6.8 obtained two years earlier based on three times the signal-to-noise ratio (S/N). It should be noted that this old definition of LoD based on 3 S/N is not equivalent to the IUPAC definition of LoD. One might conclude that the results of LoDs calculated with the ISO 11843 methodology are slightly higher than, but still comparable with, LoDs based on 3 S/N. 

This is the common definition of conformers. The IUPAC definition also requires that a conformer correspond to a distinct potential energy minimum, such as the anti and gauche conformations of butane. 

The IUPAC definition may also be extended in respect to biomimetic recognition elements, e.g., aptamers and molecularly imprinted polymers, which are derived from biology (Table). 

Refs. [i] Inczedy I Lengyel T, Ure AM (1998) Compendium of analytical nomenclature (IUPAC definitive rules, The Orange Book ), 3rd edn. Blackwell Science, Oxford [ii] Newman, Thomas-AlyeaKE (2004) Electrochemical Systems, 3rd edn. Wiley Interscience, Hoboken, pp 280... 

Vitz, Ed. Redox Redux Recommendations for Improving Textbook and IUPAC Definitions, J. Chem. Educ. 2002, 79, 397-400. 

Compendium of Analytical Nomenclature, IUPAC Definitive Rules, 1997, Third Edn., J. Inczedy, T. Lengyel and A.M. Ure, Blackwell Scientific Publications, Oxford, 1998. (The Orange Book.)... 

Unfortunately, there is no broadly valid relation between the two quantities. The activation energies of the above chlorination reactions and analogous interactions of concern in this book have not yet been reported, and their calculation from the first principles seems difficult. Meanwhile, the above supposed chlorination steps involve atoms and molecules of lower halides - the species with unpaired electrons on an otherwise open shell configuration - which is exactly the IUPAC definition... 

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