Hydroxylamine Number. Application to the Identificaton of Ketones

Trozzolo, A. M.; Lieber, Eugene

doi:10.1021/ac60042a008

Cited by 34 publications

(9 citation statements)

References 8 publications

(1 reference statement)

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“…However, it has been established that ester, carboxyl, primary and secondary amines, a-glycols, ether and allylic types of ethylenic groups do not interfere with this method. Trozzolo and Lieber (56) claimed that interfering factors such as steric effects, cyclization with the formation of isoazoxalones, conjugated unsaturation, and hydrogen bonding decreased the usefulness of such methods. Since fats contain some conjugated double bonds after oxidation, the hydroxylamine method is not really suitable for oxidation determinations.…”

Section: Total and Volatile Carbonyl Compoundsmentioning

confidence: 99%

Measurement of lipid oxidation: A review

Gray

1978

J Americ Oil Chem Soc

644

380

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Lipids become rancid as a result of oxidation, and this oxidative rancidity is a major cause of food deterioration. The acceptability of a food product depends on the extent to which this deterioration has occurred. Thus some criterion for assessing the extent of oxidation is required. This paper reviews the experimental techniques for the measurement of lipid oxidation. The spectrum of tests ranges from simple organoleptic evaluations to chemical and physical methods. There is no ideal chemical method which correlates well with changes in organoleptic properties of oxidized lipids throughout the entire course of autoxidation. The methods discussed each give information about particular stages of the autoxidative process, and some are more applicable to certain lipid systems than others. The method of choice depends on a number of factors including the nature and history of the oxidized sample, the type of information required, the time available, and the test conditions. Clearly, there is a need for a more thorough assessment of the available methods so that unreliable, cumbersome methods may be discarded and modifications made to the remaining methods to maximize the information obtained. The ultimate criterion for the suitability of any test is its agreement with sensory perception of rancid flavors and odors.

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Section: Total and Volatile Carbonyl Compoundsmentioning

confidence: 99%

Measurement of lipid oxidation: A review

Gray

1978

J Americ Oil Chem Soc

644

380

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“…18 Among the techniques they examined, that of PhillipslB was the most sensitive. ' It depended on the measurement of the difference of surface potential of two different metal plates in the gas stream.…”

Section: Discussionmentioning

confidence: 99%

Some notes on the determination of methyl ketones

1953

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Four main classes of previously known methods of determining methyl ketones have been tested and improvements have been made in some of them. The method based on pH measurements of mixtures of the ketones with hydroxylamine hydrochloride solution was shown to be most suitable for numerous routine determinations such as might be required in chromatography. I t has been known for some time that methyl ketones occur in rancid fats, particularly as a result of the activity of moulds.'* I t was therefore not surprising that they should be found in blue-vein cheese, nor that they should contribute to its flavour.s In order to help in the chemical examination of such ,materials it would be useful to have a ready means of analysis for methyl ketones. Some of the known methods give values that depend on the identity as well as on the quantities of the ketones present in a mixture, and with other methods the figures obtained cannot be related directly to flavour because of the different flavours of different ketones. Thus the ketones must be separated before progress can be made. Adsorption or partition columns offer the most promise and for the majority of these it would be necessary to break up the effluent into many samples for separate analysis. A simple, reliable and rapid method of analysis is therefore a prerequisite. Several methods taken from the literature and, in some cases, modifications of them, have been examined from this point of view and the results are presented in this paper.(1 ) Determination with salicylaldehyde Salicylaldehyde forms intense colours in the presence of methyl ketones and concentrated acid4 or alkali.5. Some years ago Taufel et aL4 attempted to make the method quantitative by the use of sulphuric acid, and they also studied its specificity. From the work of these authors it may be surmised that the method is very sensitive to the actual technique of handling, and this was found to be so. Some skill was needed to avoid charring of the samples when sulphuric acid was added and though this was readily acquired the intensity of colour was still subject to fortuitous variations. When distillates from butter or cheese were tested, atypical colours were produced. They were too yellow, although charring had been avoided, and none of the filters available permitted the measurement of the typical pink colour in the presence of the yellow.The concentration of the acid was not specified, but it is important since too high a concentration produces pink colours in the absence of methyl ketones. This was noticed when hydrochloric acid gas was bubbled into the reaction mixture. I t has recently been showns that the reaction between salicylaldehyde and acetone in the presence of potassium hydroxide can be made more reproducible if light and air are excluded, and if at least five hours elapse between warming and the final measurement of light absorption. Working with different reaction conditions Thin & Robertsonn appeared to find such precautions unnecessary; perhaps this was because their estimations we...

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“…Quantitative oximation by a modification of the method of Trozzolo and Lieber (14) has been found t o give satisfactory results with polymethyl isoCan. J. Chem.…”

Section: Oxirnationmentioning

confidence: 96%

CROSS-LINKING OF COPOLYMERS FROM METHYL VINYL KETONE AND n-BUTYL ACRYLATE

Cooper¹,

Catterall²

1956

Can. J. Chem.

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Copolymers of n-butyl acrylate and methyl vinyl ketone can be cross-linked by a combination of sulphur and zinc oxide; the reaction is associated with the methyl vinyl ltetone units in the polyn~er chain. From studies on the copolymers and model conlpounds, it is suggested that adjacent pairs or groups of methyl vinyl ketone units in the polymer cyclize t o give ap ~~n s a t u r a t e d ltetone groups. These contain reactive hydrogen which is attacked by sulphur; disulphide or zinc mercaptide cross-linlts are then formed. Water is produced in the cyclization reaction and hydrolyzes some of the ester groups; additional cross-links are thus formed by reaction of the acid groups with zinc oxide. The ease of cyclization and, therefore, the extent of cross-linking is dependent on the method of preparing the copolynlers, emulsion copolymers being much more reactive than those prepared in solution. A comparison has been made between the sulphur +zinc oxide system and other cross-linking agents which may be ~~s e d for polyacrylates.

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Hydroxylamine Number. Application to the Identificaton of Ketones

Cited by 34 publications

References 8 publications

Measurement of lipid oxidation: A review

Measurement of lipid oxidation: A review

Some notes on the determination of methyl ketones

CROSS-LINKING OF COPOLYMERS FROM METHYL VINYL KETONE AND n-BUTYL ACRYLATE

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