Identification of Organic Compounding Ingredients in Vulcanized Rubbers by Thin Layer Chromatography

1969 ◽  
Vol 42 (2) ◽  
pp. 625-635 ◽  
Author(s):  
K. Nagasawa ◽  
K. Ohta

Abstract As a result of a search for a method for the simultaneous analysis of organic compounding ingredients in vulcanized rubber by one dimensional and two dimensional thin layer chromatography, a method was discovered by which it was possible to identify directly 24 accelerators and 19 antioxidants. The sample was developed on a Wakogel B-5 (silica gel) plate with chloroform/benzene (10/9) in one direction and then with ethanol in the other direction. The plate was sprayed with formalin/sulfuric acid (1/4) and then heated for one hour at 120° C. It was found that the 43 compounding ingredients could all be identified from their Rƒ values and the colors of the spots. Good results were also obtained in the actual analysis of the organic compounding ingredients in vulcanized rubbers. Investigation of interference by the base rubbers showed that the organic compounding ingredients could be identified. Translator's note: According to the English summary, the silica gel contains 5% of calcined gypsum. This is not mentioned in the Japanese text.

INDIAN DRUGS ◽  
2015 ◽  
Vol 52 (12) ◽  
pp. 42-48
Author(s):  
P. J. Patel ◽  
◽  
D. A Shah ◽  
F. A. Mehta ◽  
U. K. Chhalotiya

A simple, sensitive and precise high performance thin layer chromatographic (HPTLC)method has been developed for the estimation of ondansetron (OND) and ranitidine (RAN) in combination. The method was employed on thin layer chromatography (TLC) and aluminium plates were precoated with silica gel 60 F254 as the stationary phase, while the solvent system was methanol. The Rf values were observed to be 0.5 ± 0.02, and 0.3 ± 0.02 for OND and RAN, respectively. The separated spots were densitometrically analyzed in absorbance mode at 299 nm. This method was linear in the range of 25-300 ng/band for OND and 50-600 ng/band for RAN. The limits of detection for OND and RAN were found to be 3.47 and 1.83 ng/band, respectively. The limits of quantification for OND and RAN were found to be 10.53 and 5.55 ng/band, respectively. The proposed method was validated with respect to linearity, accuracy, precision and robustness. The method was successfully applied to the estimation of OND and RAN in combined dosage form.


1966 ◽  
Vol 49 (4) ◽  
pp. 795-800
Author(s):  
William A Moats

Abstract Butterfat and milk samples were analyzed for chlorinated insecticides by thin layer chromatography (TLC) on aluminum oxide or silica gel plates containing a small amount of silver nitrate. The adsorbent was washed with distilled water before preparing the plates. A one-step cleanup on a partially inactivated Florisil column was performed prior to TLC analysis. For color development, the TLC plates were sprayed lightly with hydrogen peroxide to suppress possible interference from fat and then steamed before exposure to ultraviolet light to accelerate and intensify the color reaction. Rf values for a number of solvent systems on aluminum oxide and silica gel plates are given. With this procedure, 0.05 μg or less of insecticide can be detected in a 0.4 g butterfat sample or the extract from 10 ml milk.


1983 ◽  
Vol 56 (5) ◽  
pp. 1080-1095 ◽  
Author(s):  
B. J. Gedeon ◽  
T. Chu ◽  
S. Copeland

Abstract TLC is a quick, easy method to the identification of rubber compounding ingredients. Both silica gel absorbent and C18 absorbent are suitable for these identifications. With the mobile phases used in this study, a better separation of antioxidants is possible using silica gel absorbent. Work should be continued on finding suitable mobile phases for the C18 absorbent, since the Rf values are more reproducible. For those separations that require a separation of compounds of varying molecular weight, the C18 absorbent is superior to silica gel absorbent. The visualization systems that have been developed for use with silica gel absorbent are suitable for use with C18 absorbent. These systems give the same colors for either absorbent.


1979 ◽  
Vol 62 (4) ◽  
pp. 917-920 ◽  
Author(s):  
Irene Kushnir

Abstract A highly sensitive procedure has been developed to detect the undeclared addition of high fructose corn sirup (HFCS) to honey. Carbohydrates must be separated first to achieve the requisite degree of sensitivity: charcoal-Celite chromatography was used to isolate a fraction containing oligo- and polysaccharides. The fraction was then concentrated and examined by thin layer chromatography on silica gel. Pure honeys yielded only 1 or 2 blue-grey or bluebrown spots at Rf values >0.35; a series of spots or blue streaks extending from the origin characterized adulterated samples. The method detects HFCS and conventional honey adulterants at levels as low as 10% or less of the total mixture. In addition, the procedure detects the presence in honey of all starch-derived sugar sirups tested thus far, regardless of the plant source.


1966 ◽  
Vol 49 (4) ◽  
pp. 807-809
Author(s):  
Shirley A Scheidt ◽  
Harry W Conroy

Abstract PG, NDGA, BHT, and BHA were extracted with acetonitrile from fat or oil, followed by thin layer chromatographic separation and identification. The four antioxidants were distinctly separated from one another by one-dimensional solvent development of the silica gel adsorbent layer. The chromatography required < 1 hour from spotting to visualization with 2,6-dichloroquinone chlorimide. As little as 1 μg of BHT and 0.5 μg of PG, NDGA, and BHA were detected by this method.


1965 ◽  
Vol 22 (1) ◽  
pp. 17-25 ◽  
Author(s):  
M. Yurkowski

Methods are described for the separation of 2,4-dinitrophenylhydrazones of normal aliphatic monocarbonyl compounds by thin-layer chromatography. Magnesia-cellulose thin-layer plates are used to separate mixtures of these compounds into classes (n-alkanals, n-alkan-2-ones, n-alk-2-enals, and n-alka-2,4-dienal). Propylene glycol- and petrolatum-impregnated silica gel plates were also used to separate each class into homologues. The former impregnant resolved the compounds with less than seven carbons and the latter with more than six carbons. Two-dimensional separation was accomplished by resolving a mixture of these compounds into classes on magnesia-cellulose in the first dimension and the classes into homologues on either petrolatumor propylene glycol-impregnated silica gel plates in the second dimension.


1970 ◽  
Vol 16 (8) ◽  
pp. 662-666 ◽  
Author(s):  
F Kraffczyk ◽  
R Helger ◽  
H Lang

Abstract Separation of the amino acids in urine by use of thin-layer chromatography (TLC) has hitherto required that the specimen be first desalted and then chromatographed in two dimensions with at least two pairs of developing solvent systems. We wished to simplify both steps. The customary method of desalting on a column is replaced by desalting on a plate that supports a strongly acid cation-exchanger and a cellulose layer. This method, originally developed for one-dimensional TLC, is used here for two-dimensional TLC. Urine is applied to the ion-exchange layer and strong acids and neutral substances are removed with water. The amino acids are then chromatographed into the cellulose layer, and are separated there two dimensionally with a newly devised pair of developing solutions. This pair of solvents separates nearly all of the amino acids in urine.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Elżbieta Matysik ◽  
Anna Woźniak ◽  
Roman Paduch ◽  
Robert Rejdak ◽  
Beata Polak ◽  
...  

The new mode of two-dimensional gradient thin layer chromatography (MGD-2D TLC) has been presented. Short distance development of sample in the first dimension leads to formation of the preconcentrated narrow zones. They are consecutively separated in the second dimension with the mobile phase gradient in several steps of development until the eluent reaches the further end of the chromatographic plate. The use of the above-mentioned technique allows isolating and then identifying the compounds of various polarity from the multicomponent mixture. The practical application of two-dimensional gradient thin layer chromatography has been performed for isolation of the two plant (JuniperusandThymus) oils components as the examples of test mixtures. The experiments have been carried out with the use of silica gel plates as well as a normal phase condition. The results of solute separation with isocratic one-dimensional thin layer chromatography system have been compared with those of two-dimensional gradient system. It has been observed that application of the latter mode leads to almost triplicated number of zones in comparison with the former one. It is purposeful to apply the proposed mode to control the purity of the dominant component or components of the mixture.


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