Chromatographic Detection of Flavor Additives in Vanilla Extract

1964 ◽  
Vol 47 (3) ◽  
pp. 551-555
Author(s):  
S Kahan ◽  
J Fitelson
Keyword(s):  
Thin Layer ◽  
Collaborative Study ◽  
The Other ◽  
Sensitive Test ◽  
Ethyl Vanillin ◽  
Modified Method ◽  
Layer Method ◽  
Layer Technique ◽  
Thin Layer Method ◽  
Chromatographic Detection

Abstract Two chromatographic methods, one a thin-layer technique and the other paper chromatography, were developed for five flavoring additives and submitted to collaborative study. The thinlayer method gave good results and proved to be a rapid and sensitive test. However, some of the features of the method required further study to improve the identification of the separated spots. A better test for coumarin and another solvent giving greater separation between the ethyl vanillin and veratraldehyde spots were developed. The modified method has been recommended for adoption as official, first action. Some analysts attained good results with the paper chromatographic test; others, even experienced analysts, got poor results. Some of the difficulty was traced to variations in composition of reagents, but the method needs further study to standardize conditions. This method was not recommended for adoption. The proposed chromatographic thin-layer method offers a rapid means of detecting ethyl vanillin, veratraldehyde (methyl vanillin), coumarin, piperonal (heliotropin), and vanitrope (propenyl guaethol).

Chromatographic Detection of Flavor Additives in Vanilla Extract

1965 ◽  
Vol 48 (3) ◽  
pp. 507-508
Author(s):  
S Kahan ◽  
J Fitelson
Keyword(s):  
Thin Layer ◽  
Silica Gel ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Layer Method ◽  
Thin Layer Method ◽  
Chromatographic Detection

Abstract A second collaborative study was conducted on a thin-layer chromatographic method for the detection of flavor additives, adopted as official, first action last year. Fifteen collaborators reported successfully on the presence of added flavoring materials in fovir unknown samples. Some collaborators found significant variations in the activity of the Silica Gel G used to make the thin-layer plates, and a precautionary statement has been inserted in the method to detect svich inactive or overactive reagents. As a result of this study, the thin-layer method has been recommended for adoption as official, final action.

Analysis of Ochratoxins A and B and Their Esters in Barley, Using Partition and Thin Layer Chromatography. II. Collaborative Study

1973 ◽  
Vol 56 (4) ◽  
pp. 822-826
Author(s):  
Stanley Nesheim
Keyword(s):  
Thin Layer ◽  
Ochratoxin A ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Ethyl Esters ◽  
The Other ◽  
Average Recovery ◽  
Confirmation Test ◽  
Two Samples ◽  
Layer Chromatography

Abstract To test the method of Nesheim et al., 6 samples wert; analyzed in 13 laboratories. The samples encompassed a blank and 5 samples containing one or more ochratoxins in the range 50–200 μg/kg. Two samples were spiked with the 4 ochratoxin standards and 3 were spiked with barley naturally contaminated with ochratoxin A. The confirmation of identity of ochratoxins A and B by preparation of their ethyl ester derivatives was also tested. The average recovery of standard ochratoxin A was 112% at levels of 45 and 90 μg/kg, with a 27.1% coefficient of variation calculated from analysis of variance, one analyst, one replicate. Similar satisfactory results were obtained for the ethyl esters of A and B at a level of 120 μg/kg. The results were unsatisfactory for ochratoxin B and for the esters of A and B at the 60 μg/kg level. The chemical confirmation test was satisfactory for both ochratoxins A and B. The method, including chemical confirmation, has been adopted as official first action as quantitative for ochratoxin A and qualitative for the other toxins.

scholarly journals The thin-layer method in a cross-anisotropic 3D space

2011 ◽  
Vol 89 (5) ◽  
pp. 537-560 ◽  
Author(s):  
João Manuel de Oliveira Barbosa ◽  
Eduardo Kausel
Keyword(s):  
Thin Layer ◽  
3D Space ◽  
Layer Method ◽  
Thin Layer Method

scholarly journals Die meting van die suurstofbindingseienskappe van hemosianien met die hulp van ’n dunlaag optiese sel

1992 ◽  
Vol 11 (2) ◽  
pp. 62-68 ◽  
Author(s):  
W. J. Van Aardt
Keyword(s):  
Thin Layer ◽  
Absorption Peak ◽  
Oxygen Binding ◽  
Initial Value ◽  
Marisa Cornuarietis ◽  
High Affinity ◽  
Layer Method ◽  
Thin Layer Method

The merits of the thin-layer method of Dolman and Gill to study the oxygen binding of haemocyanin were experimentally tested with haemocyanin obtained from arthropods and molluscs. The results show that, spectrophotometrically, oxyhaemocyanin from both arthropods and molluscs has a prominent absorption peak between 335 and 345 nm. Haemocyanin is more stable in the thin- layer preparation when compared with haemoglobin. At 35 °C a decrease in the initial absorbance value of less than 2% was found after three hours. For haemoglobin the initial value decreases nearly 10% during the same period. For a high-affinity haemocyanin such as Marisa cornuarietis (P⁵⁰ = 1,07 mmHg) the thin-layer method of Dolman and Gill (1978) shows better PO₂ resolution than other methods. The reason for this is that the dilution valve, which is absent in other thin-layer methods, intrinsically measures the resultant PO₂ values at very low tensions more accurately. In this study a step-by-step explanation of the technique is given. The calculations have been explained using real figures and examples. It is hoped that this detailed description will make this technique more readily available for use by respiratory physiologists.

scholarly journals MALDI Sample Preparation: the Ultra Thin Layer Method

10.3791/192 ◽  
2007 ◽  
Author(s):  
David Fenyo ◽  
Qingjun Wang ◽  
Jeffrey A. DeGrasse ◽  
Julio C. Padovan ◽  
Martine Cadene ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Thin Layer ◽  
Layer Method ◽  
Thin Layer Method ◽  
Maldi Sample

On the accuracy of some approximate antiplane half-space stiffnesses

1991 ◽  
Vol 81 (4) ◽  
pp. 1340-1359
Author(s):  
Toshiro Maeda ◽  
Eduardo Kausel
Keyword(s):  
Thin Layer ◽  
Half Space ◽  
Green's Functions ◽  
Green’S Functions ◽  
Finite Depth ◽  
Point Of View ◽  
Computational Domain ◽  
Efficient Computation ◽  
Layer Method ◽  
Thin Layer Method

Abstract The modeling with discrete methods of elastic media of infinite extent that are subjected to dynamic loads normally calls for the use of special transmitting (or nonreflecting) boundaries. One such discrete method is the thin layer method, which allows efficient computation of the Green's functions for layered soils of finite depth; its application to elastic half-spaces, however, requires that the infinite medium be represented by means of approximations that are analogous to transmitting boundaries. In this article, we explore the accuracy of two of these approximations in the context of the Green's functions for antiplane (or SH) line loads. We find that the paraxial approximation of Engquist - Majda gives good results, provided that a “buffer layer” with the same material properties as the half-space separates the computational domain from the transmitting boundary. While these results were studied from the point of view of the thin layer method, they apply equally well to models with finite elements or finite differences.

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