Separation of 2,4-Dinitrophenylhydrazones of Aldehydes and Ketones by Paper Chromatography

Lynn, William S.; Steele, L.; Staple, Ezra

doi:10.1021/ac60109a045

Cited by 64 publications

(23 citation statements)

References 7 publications

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“…In any event on further column chromatography of fraction 14 neither pure n-butanal nor methyl-ethyl-ketone derivative could be obtained. However Lynn et al (7) have shown that these 2 hydrazones may be readily separated by paper chromatography and when fraction 14 was so chromatographed, 2 well-separated spots, moving distances identical to those of authentic n-butanal and methyl-ethyl-ketone 2,4-dinitrophenylhydrazones were obtained. I n addition the infrared spectrum of fraction 14 was compatible with the fact that it was a mixture of these 2 derivatives.…”

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confidence: 99%

Volatile Carbonyl Compounds of Cooked Chicken. I. Compounds Obtained by Air Entrainment

Pippen

Nonaka

Jones

et al. 1958

Journal of Food Science

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Progress toward production of poultry products having stable and optimum flavor depends considerably on obtaining increased insight into the f undamental causes of flavor and off flayor of the products. To provide part of this basic information, studies on composition of the volatile fraction of cooked chicken have been in progress at this laboratory. A previous paper (12) reported properties of volatile sulfur and nitrogen compounds. The investigation reported here describes a method of isolating volatile carbonyl compounds from cooked chicken, as the 2,4-dinitrophenylhydrazone derivatives, and the subsequent chromatographic separation of the mixed hydrazones into fractions which enabled identification of many of the carbonyl compounds. EXPERIMENTALIsolation of volatile carbonyl compounds from cooked chicken. Throughout the study, 2,4-dinitrophenylhydrazine ( 2 g. per liter of 2 N HCl) reagent was used to detect presence of carbonyl compounds. Three sets of conditions for isolating volatile carbonyl compounds were considered. These comprised recovery of volatiles evolved from chicken cooked under (a) normal cooking conditions, (b) oxidation-inhibiting conditions, and (c) oxidation-favoring conditions. For condition (a), chickens were simmered in water for 3 hours and distillate of the resulting broth was tested for presence of carbonyl compounds. For conditions (b) and (c), a stream of nitrogen and air, respectively, were passed through each system during cooking, not only to provide an inert and oxidative atmosphere, but also to entrain and sweep volatile components into the detecting reagent. A volatile carbonyl fraction was detected for all 3 isolation methods. Preliminary chromatography of the hydrazones on silicic acid-Celite columns, as described below, showed that regardless of the isolation method a complex mixture of hydrazones was obtained. Of the 3 methods, the one favoring oxidation gave the greatest yield of carbonyl while the one utilizing a nitrogen atmosphere gave the lowest yield. In some respects method (a), based on a normal cooking procedure and utilizing chicken broth distillate, which has been shown (12) to contain detectable flavor, would be a logical starting point for this investigation. However it was decided to study the qualitative nature of the carbonyl fraction isolated by both methods (a) and (c). Such a comparison would show whether a qualitative as well as a quantitative difference exists in the carbonyl fraction isolated and might provide some clues about the nature of carbonyl compounds which are associated with both normal and oxidative off flavors. I t was decided to work first on carbonyl compounds isolated by the atypical oxidation-favoring cooking conditions described below, because this method provided a yield of carbonyl compounds sufficient to make identification of minor constituents seem feasible.The apparatus used for isolation of carbonyl compounds as 2,4-dinitrophenylhydrazones is shown in Figure 1.

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confidence: 99%

Volatile Carbonyl Compounds of Cooked Chicken. I. Compounds Obtained by Air Entrainment

Pippen

Nonaka

Jones

et al. 1958

Journal of Food Science

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“…Orange-yellow 2:4-dinitrophenylhydrazone precipitated (2 mg.), which was partly crystalline. On paper chromatograms run under the conditions described by Lynn, Steele & Staple (1956) this product yielded three yellow spots corresponding in RF values with the 2:4dinitrophenylhydrazones of formaldehyde, acetaldehyde and isobutyraldehyde. isoButyraldehyde and formaldehyde might have been formed by periodate oxidation of the diol (CH3)2-CH -CH(OH) -CH2 OH.…”

Section: -2mentioning

confidence: 87%

The structure of cephalosporin C

Abraham

Newton

1961

Biochemical Journal

269

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“…Recently, a number of workers have applied paper chromatography to the separation of 2,4-dinitrophenylhydrazine derivatives of carbonyl compounds ( I , 4,7,10). Although such methods have limitations, they are relatively simple, and lend themselves to both qualitative and quantitative determinations by means of spectrophotometry ( 4 , 6).…”

Section: The Carbonyl Compoundsmentioning

confidence: 99%

“….09 (6) .05 (7) .02 (8) .oo Some tentative conclusions regarding the neutral carbonyl compounds are listed in Table 3. These conclusions are not based on & values as such, but on the results of many chromatograms spotted with various combinations of known compounds together with the coffee mixtures.…”

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confidence: 99%

A Chromatographic Study of Some of the Compounds in Roasted Coffee

Clements

Deatherage

1957

Journal of Food Science

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Flavor is the most important factor in coffee from the standpoint of the consumer. It is known that the green coffee itself, its handling, manner of roasting, grinding, storage, method of brewing and handling after brewing, all affect flavor ; yet, an understanding of the chemical nature of flavor and changes in flavor of coffee remains to be found. It was thought that some of the newer chromatographic techniques might be adapted to a study of compounds which might be important in coffee flavor and helpful in determining which substances are native to coffee and which are produced in roasting. There is also the possibility that information on the nature of staling, on flavor changes in boiling brewed coffee, and on some of the more subtle changes in flavor might be found. The methods employed indicated many compounds which have not been identified as yet; some of these are native to coffee and some are produced by roasting. Although some of these compounds are not yet even tentatively identified, the reproducibility and the characteristic nature of the chromatograms indicated the value of the methods developed. Also, the techniques appeared to be applicable to other food. Consequently, this report does not await complete identification of all unknown substances observed. EXPERIMENTAL Non-volatile acids and phenolsMaterials. Roasted Coflee. Unless otherwise specified, the analyses were performed on that coffee obtained from The Coffee Brewing Institute, Inc., and hereafter referred to as standard coffee. Other samples were purchased locally.Green coffee: A ground sample of Santos coffee was used. Chromatographic solvents: Dimethylformamide, cyclohesane, and t-butyl alcohol were technical grades. For heptane, Skellysolve-C was used. All other solvents were reagent grade. None of the solvents was further purified.Procedures. Preparation of estracts: A series of extracts was prepared as follows: Distilled water (500 ml.) was added to ground roasted coffee (100 9.) and the mixture was placed in a refrigerator (2" C.) for 2-3 days. The grounds were removed by filtration, and a second extraction of the same grounds was carried out at 85-90" C.The grounds were again removed and finally extracted with boiling water. Ecah of the above 3 extracts was divided into 2 portions, one of which was acidified and the other made alkaline. The 6 extracts were finally concentrated t o syrups by distillation under reduced pressure. I n addition t o these extracts, acidic and alkaline concentrates of green coffee (extracted at 85-90" C.) were prepared.Paper chromatography. The chromatographic procedure and indicators were essentially those of Buch et al.(3), with iso-amyl alcohol (rather than n-amyl alcohol) constituting the moving solvent.

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Separation of 2,4-Dinitrophenylhydrazones of Aldehydes and Ketones by Paper Chromatography

Cited by 64 publications

References 7 publications

Volatile Carbonyl Compounds of Cooked Chicken. I. Compounds Obtained by Air Entrainment

Volatile Carbonyl Compounds of Cooked Chicken. I. Compounds Obtained by Air Entrainment

The structure of cephalosporin C

A Chromatographic Study of Some of the Compounds in Roasted Coffee

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