Relative molecular mass definition

Water soluble protein with a relative molecular mass of ca. 32600, which particularly contains copper and zinc bound like chelate (ca. 4 gram atoms) and has superoxide-dismutase-activity. It is isolated from bovine liver or from hemolyzed, plasma free erythrocytes obtained from bovine blood. Purification by manyfold fractionated precipitation and solvolyse methods and definitive separation of the residual foreign proteins by denaturizing heating of the orgotein concentrate in buffer solution to ca. 65-70 C and gel filtration and/or dialysis. 

A small amount of the substance is accurately weighed, dissolved and made up carefully in a volumetric flask. to a definite volume, e.g. 100 ml. From the known relative molecular mass (RMM) of the compound it is possible to calculate the molar concentration of the solution ... 

Note 2 In the literature, the term macrocycle is sometimes used for molecules of low relative molecular mass that would not be considered macromolecules as specified in Definition 1.1. 

The situation is different for aqueous species of humic substances, the organic matter in soil that is not identifiable as unaltered or partially altered biomass or as conventional biomolecules.21 Humic substances comprise organic compounds that are not synthesized directly to sustain the life cycles of the soil biomass. More specifically, they comprise polymeric molecules produced through microbial action that differ from biopolymers because of their molecular structure and their long-term persistence in soil. This definition of humic substances implies no particular set of organic compounds, range of relative molecular mass, or mode of chemical reactivity. What is essential is dissimilarity to conventional biomolecular structures and biologically refractory behavior. 

An earlier off-odor problem that surfaced was the presence of 4-phenyl-cyclohexene in styrene-butadiene coated paper (Koszinowski et al. 1980). This compound was created by a Diels-Alder condensation reaction involving a molecule of styrene and butadiene and is differentiated by its odor from the isomeric 3 and 1-phenyl-cyclohex-ene compounds which cannot be formed by such a condensation reaction. The recognition threshold of this compound in the headspace over an aqueous solution lies around a concentration of 10 pg/kg (10 ppb). The typical odor of this compound at concentrations of 4-phenyl-cyclohexene in paper over 4 mg/kg (4 ppm) is easily identified. AGC determination in this concentration range is also possible without difficulty and its identification with MS using the relative molecular mass of 158 and one of the retro Diels-Alder decomposition product fragments at m/e = 104 (styrene) and mJe = 54 (butadiene) is definitely possible. 

Partial molar entropies of ions can, for example, be calculated assuming S (H+) = 0. Alternatively, because K+ and Cl ions are isoelectronic and have similar radii, the ionic properties of these ions in solution can be equated, e.g. analysis of B-viscosity coefficients (Gurney, 1953). In other cases, a particular theoretical treatment which relates solvation parameters to ionic radii indicates how the subdivision could be made. For example, the Bom equation requires that AGf (ion) be proportional to the reciprocal of the ionic radius (Friedman and Krishnan, 1973b). However, this approach involves new problems associated with the definition of ionic radius (Stem and Amis, 1959). In another approach to this problem, the properties of a series of salts in solution are plotted in such a way that the value for a common ion is obtained as the intercept. For example, when the partial molar volumes of some alkylammonium iodides, V (R4N+I ) in water (Millero, 1971) are plotted against the relative molecular mass of the cation, M+, the intercept at M + = 0 is equated to Ve (I-) (Conway et al., 1966). This procedure has been used to... 

There is no universally accepted definition of starch with regard to minimum chain length or relative molecular mass. A common way of defining starch is by stipulating a certain concentration of ethanol in water solution in which the starch fraction is insoluble. The popular concept of the controlling medium for starch qualification is a 40%, v/v, ethanol solution. 

The behaviour of materials of low relative molecular mass is usually discussed in terms of two particular types of ideal material the elastic solid and the viscous liquid. The former has a definite shape and is deformed by external forces into a new equilibrium shape on removal of these forces it reverts instantaneously to its original form. The solid stores all the energy that it obtains from the external forces during the deformation, and this energy is available to restore the original shape when the forces are removed. By contrast, a viscous liquid has no definite shape and flows irreversibly under the action of external forces. 

Based on the definition of the relative molecular mass Mr, it is seen that it corresponds to the sum of the masses of the constituent atoms A. The relative molecular mass Mr, often denoted molecular mass, is a non-dimensional quantity. 

To give a clear and precise definition of the term polymer is the intention of lUPAC "A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass."... 

Webster s definition for database is a large collection of data in a computer, organized so that it can be expanded, updated, and retrieved rapidly for various uses. An LC/MS database established for drug impurities contains multi-dimensional information such as relative retention times, UV spectra, molecular mass and substructural information. In order for the information to be updated and expanded, the methods used for information collection need to be unified. A generic LC/MS method allows relevant information to be collected in a consistent... 

Orientation (Chapter 5) refers to the preferred positioning of parts or groups of molecules in the bulk phase without the establishment of long-range order. Crystallinity (Chapter 5) presupposes not only a three-dimensional preferential arrangement of the chains, but also definite interrelationships between the lattice points. The chain atoms, with their substituents, can be considered as lattice points. Thus, with polymers, in contrast to low-molecular-mass chemistry, it is not the mutual arrangement of the lattice points of various molecules which must be considered, but also the arrangement of the lattice points of an individual macromolecule relative to the other lattice points of the same molecule. 

---