Hanus method

Catalytical studies of synthesized products were tested according to the Hanus Method [18]. Since Triglycerides (fats and oils) are esters of glycerol with three fatty acids. These long chain fatty acids may contain one or more double bonds. With no double bonds, the fatty acid is termed saturated (with hydrogen), and with double bonds, it is termed unsaturated. The iodine number is an indication of the degree of unsaturation of the oil (Scheme 14.4). 

Iodine Value (or Number)—the percentage of iodine that will be absorbed by a clieimcally unsalurated substance, such as vegetable oil, in a given time under specified conditions. The iodine value is a measure of degree of unsaturation. Two methods are described in the Food Chemicals Codex the Hanus method and the Wijs method. 

Hanus method, used by the U,S,P, is equivalent to the Wijs method and the same process is followed, thirty minutes being allowed for absorption of all oils and fats except castor, cod-liver and linseed oils, which are allowed to stand for one hour. The Hanus iodobromide solution is made by dissolving 13 2 g of iodine in 1 litre of glacial acetic acid and then, to the cold solution, a quantity of bromine is added equivalent to that of the iodine present the iodine present is determined by titration. 

The methods for determining the iodine value of lipids are Hanus method and Wijs method. The lipid to be analyzed is weighed and dissolved in a suitable organic solvent, to which a known excess of iodine monobromide (or the monochloride) is added. Some of the IBr reacts with the double bonds in the imsaturated lipids, whereas the rest remains unreacted ... 

Owiag to incomplete halogea absorption, iodiae values for conjugated acid oils by the usual methods (Wijs, Hanus, etc) are both low and variable. The tme value of fresh tung oil, as determined by a special method (13), is 248—252 that of oiticica oil is 205—220. 

Hanus recommends that )S-naphthyl hydrazine hydrochloride should be added to the solution of vanillin in such pioportion that from two to three parts are present for each part of vanillin. After standing for five hours the precipitate is transferred to a tared filter, washed with hot water until the washings no longer precipitate silver nitrate, dried at 90° and weighed. The weight of the hydrazine formed, divided by 1-92 gives that of the vanillin present. This method is avaUable in all cases where an aqueous solution of the vanillin can be prepared. 

Hanus has more recently recommended the following method for the determination of vanillin in vanilla beans and in preparations thereof. Three grams of the crushed pods are extracted for three hours in a Soxhlet tube with ether, the solvent distUled off cautiously, and the residue dissolved in a little ether, the solution filtered and the filtrate evaporated cautiously. The residue is treated with 50 c.c. of water at 60° on a water-bath 0 25 gram of weto-nitrobenzhydrazide is then added to the aqueous solution in a stoppered flask, which is kept for two to three hours... 

Semioxamazide.—A gravimetric method for the estimation of cinnamic-aldehyde in cassia and cinnamon oils, but which appears to apply only to this aldehyde, has been devised by Hanus based on the formation of a crystalline semioxamazone when cinnamic aldehyde is treated -with semioxamazide, the reaction being—... 

Other methods for the determination of aldehydes and ketones are those of Bene-dikt and Strache (carbonyl number), Hanus (phenylhydrazine), and Bennett (hydroxyl-amine hydrochloride). See Charabot, Dupont et Pillet Les Huiles essentielles, 1899. 

The carbonyl number method gives moderately exact results for the determinations of benzaldehyde in bitter almond oil, of cuminaldehyde in cumin oil and of methyl nonyl ketone in rue oil. The method devised by Hanus gives, according to this author, good results for the amount of cinnamaldehyde in cinnamon oil. 

Early studies involving NMR include the work by Hanus and Gill is [6] in which spin-lattice relaxation decay constants were studied as a function of available surface area of colloidal silica suspended in water. Senturia and Robinson [7] and Loren and Robinson [8] used NMR to qualitatively correlate mean pore sizes and observed spin-lattice relaxation times. Schmidt, et. al. [9] have qualitatively measured pore size distributions in sandstones by assuming the value of the surface relaxation time. Brown, et. al. [10] obtained pore size distributions for silica, alumina, and sandstone samples by shifting the T, distribution until the best match was obtained between distributions obtained from porosimetry and NMR. More recently, low field (20 MHz) NMR spin-lattice relaxation measurements were successfully demonstrated by Gallegos and coworkers [11] as a method for quantitatively determining pore size distributions using porous media for which the "actual" pore size distribution is known apriori. Davis and co-workers have modified this approach to rapidly determine specific surface areas [12] of powders and porous solids. 

Very little is known about the biosynthesis of the three most recently proposed endocannabinoids, 2-AGE, virodhamine and NADA. Regarding 2-AGE (noladin ether), this compound was previously identified in pig brain (Hanus et al. 2001) and in some rat tissues and brain areas (Fezza et al. 2002) by using mass-spectrometric (MS) methods coupled to chromatographic separations. However, a recent study cast some doubt on the actual existence of 2-AGE in mammalian brain tissue (Oka et al. 2003). At the time of this study it was already known that (1) the only acyl ethers to have been detected in animals before the discovery of 2-AGE were 2-acyl ethers (e.g. alkenyl ethers such as platelet activating factor and plasmalogens) (2) there was no evidence for the existence of any enzyme catalysing the formation... 

Hanus iodine number n. Method claimed to measure the complete unsaturation of both conjugated and non-conjugated substances. The method employs as a reagent a solution of iodine and bromine in glacial acetic acid. 

Hanus publishes a new method for the determination of cinnamic aldehyde in cassia and cinnamon oils depending on the comibination of the aldehyde with semioxamazide. Ten grms. of finely powdered hydrazine sulphate are dissolved in a solution of 9 grms. of caustic soda... 

Wijs Method Analytical method for determining the degree of unsaturation of a material, which involves the addition of iodine to the existing double bonds. The iodine is derived from a solution of iodine monochloride in glacial acetic acid. See Iodine Test and Iodine Value Hanus Iodine Number Wilkinite See Bentonite. 

The following modified method, that of Hanus, is of general application and serves also in technical analysis for the determination of the iodine numbers of natural products such as fats, fatty acids, waxes, etc. 

Double-bond content 12 in polymer <0.05% (Hanus IBr method)... 

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