Evaluation of the turbidity and thin layer chromatographic tests for detection of castor oil

Detection procedures for castor oil in genuine and treated groundnut oils were screened and false turbidity was noticed when ammonium molybdate/sulfuric acid reagents were added to rancid groundnut oil. Successively bleached and neutralized rancid groundnut oil samples do not respond to the tests. Turbidity did not appear for groundnut oils containing 10 and 20% castor oil and even for pure castor oil sample. Thin layer chromatography (TLC) was found to be quite effective for most of the treated, adulterated, genuine, old and fresh oil and fat samples, but showed a streaking, when applied to rancid groundnut oil. However, streaking could be greatly reduced and TLC could be successfully performed with bleached and neutralized, rancid groundnut oil samples.     

Detection of palm oil in vanaspati by thin layer chromatography

Palm oil (raw or refined), as such, or the unsaponifiable matter of palm oil and vanaspati (mostly hydrogenated soybean oil containing 5% sesame oil), when separated on a silver nitrate impregnated Silica Gel G plate or a Silica Gel G plate using (a) hexane/ether/acetic acid (80:20:1.5) or (b) chloroform, respectively, for development showed distinct differences. On the basis of this, two systems have been suggested for the detection of palm oil in vanaspati. About 5% adulteration can be detected by the first method and 10% by the second.     

Detection of adulteration of olive oil by argentation thin layer chromatography

Minute amounts of adulterant seed oils in olive oil can be detected by GLC analysis of fatty acids of the polyunsaturated triglyceride fraction, obtained by TLC on silver nitrate impregnated silica gel. Every possible effort was made to avoid any critical or time consuming manipulation in this method in order to develop it as a routine testing procedure. A complete analysis is possible in less than 2 hr and the detection of as low as 2% adulteration by other seed oils is accurate and reliable.     

薄层色谱分析在层析分离过程中的应用

介绍了薄层色谱分析方法对层析分离过程的控制性分析和优化作用。     

Some biophysical properties of castor oil esterified with some acid anhydrides

A series of castor oil adducts were synthesized by esterification of castor oil with acid anhydrides: phthalic, maleic and succinic anhydrides. The chemical structure of castor oil and the prepared adducts were characterized by means of IR and ¹H NMR spectroscopy. The number‐average and weight‐average molecular weights were measured by gel permeation chromatography. The electrical properties were studied through the permittivity, dielectric loss and conductivity measurements, which are considered to be in the range of electrical insulation. The electrical conductivity, which describes the ionic mobility of the systems, was found to be in the range of 10^–9 to 10^–12 S/cm. This indicates that castor oil and its esters could be used for antistatic applications. The viscosity η and the activation energy E_η, obtained from the dependency of viscosity on temperature using the Arrhenius equation, were found to increase with increasing molecular weight of the system. The effect of different concentrations of castor oil and its esters on the growth activities of the sugar beet pathogens R. solani and S. rolfsii was studied through the determination of percent germination, average length of hyphal extensions, dry mass yield and the production of sclerotia. The obtained data indicate that the esterification of castor oil with anhydrides improves the antifungal activity.     

Complexities in lipid quantitation using thin layer chromatography for separation and flame lonization for detection

The use of thin layer chromatography (TLC) for separation (using silica gel coated quartz rods) and subsequent flame ionization for detection (FID) was examined to determine whether this method could be used for the quantitation of lipids. However, response factors (RF) for various lipids were different and depended upon several variables including the amount of material analyzed. For example, RF were 3-fold greater when 10 μg of tripalmitin was analyzed as compared to 1 μg of the same material. The amount of lipid detected by FID was also dependent upon the rate at which it passed through the flame. During analysis of methylpentadecanoate, detector response increased with scan speed, while at all speeds it was completely removed from the rod. On the other hand, depending upon the amount of cholesterol or phospholipid analyzed, the response either increased, remained unchanged or decreased with scan speed. During a fast scan, detector response was reduced because some material remained on the rod. Thus, the detector response is influenced by sample volatility. In conclusion, there appears to be a complex relationship between detector response and the amount of heat available per microgram of sample. Since we could not find a direct correlation between detector response and sample quantity, it would be difficult to use TLC-FID as a tool for quantitating the components of a lipid mixture. Presented at the 73rd Annual AOCS Meeting, Toronto, May 1982.     

Applicability of the turbidity test for castor oil to some other hydroxy and epoxy fatty compounds

A large number of hydroxy as well as nonhydroxy fatty compounds were employed to explore the applicability of the turbidity test for castor oil (1) and to understand the nature of the turbidity. The test was capable of detecting up to ca. 2% of hydroxy, hydroperoxy, and epoxy fatty acids and their esters, also the epoxy, acetoxy, and hydroxy fatty alcohols present in a petroleum ether solution of a nonpolar triglyceride oil. Monohydric primary alcohols, sterols, mono- and diglycerides were not detected. The turbidity developed, whether H₂SO₄ contained ammonium molybdate or not, because of the formation of a sulfate and its precipitation from the petroleum ether solution of oil.     

Conditions and techniques for thin layer chromatography of aflatoxins

Satisfactory resolution of the four common aflatoxins, B₁, B₂, G₁ and G₂, on thin layer chromatograms has been a recurring problem. The most frequently observed cause of poor resolution and tailing of spots in the chromatograms was the variable properties of the commercial silica gel-calcium sulfate adsorbent preparations. Variations in quality were observed even from one container to the next within single lots produced by individual manufacturers. Other variables which affected the chromatography to some degree included adsorbent particle size, concentration and nature of the calcium sulfate binder, silica gel layer thickness and moisture content, vapor phase composition in the developing chamber and the solvent used for development.     

Some observations on the rapid chemical test for potentially reactive aggregate

The chemistry of the ‘rapid chemical test’ is discussed. The choice of phenolphthalein as indicator is a poor one, and the difference in the end-point to phenolphthalein and methyl orange is a function of dissolved silica, as well as of any CO₂ content. Suggestions for possible improvements are made.     

Some observations on the long-term behavior of stabilized polyethylene

Much has been written on the theoretical mechanisms by which the oxidation of polyolefins is believed to proceed and on the role of stabilizers in impeding this process. Relatively little information is available on the effects of some of the interesting, practical considerations—stress, stabilizer stability and the consequences of crystalline content and texture to name a few—which exert a controlling influence on the behavior of these materials in real-life situations. Data are presented on the aging behavior of low- and high-density polyethylenes at temperatues in the range 50-110°C in the presence of copper and on the utility and limitations of oxygen absorption and differential thermal analysis as tools for accelerated prediction of this behavior.     

Some observations on the determination of soap in refined oil

Recovery experiments which were made by two quite different procedures indicate that the most satisfactory approach to a solution of the problem of determining the soap content of a refined oil probably rests upon the assumption that the chloride which is formed upon the addition of hydrochloric acid is an index of the quantity present. At soap concentrations of 100 pts/M² and less, the Durst method, as modified by Stillman, was found to be quantitative for all practical purposes.     

Use of inverse thin layer chromatography with amino acids to characterize molecular interactions on conducting polymers

A new method for characterizing conducting polymers, based on thin layer chromatography, is evaluated. Polypyrrole and polyaniline were used as the stationary phase and molecular probes were used to characterize favourable interactions on the polymers. Amino acids were chosen as the molecular probes because of the range of properties they exhibit and because there are numerous methods for their detection. Some difficulties were experienced in preparing stationary phases with suitable physical properties. However, once this was overcome, useful information was obtained with inverse TLC. Polypyrrole and polyaniline were both found to behave predominantly as anion-exchange materials.     

Some observations on the flow behavior of polyvinyl chloride melts

Melt studies on PVC systems at elevated temperature or long times are difficult. One consequence is that measurements may be possible only in the non-Newtonian region. The results indicate that even in this case the melt viscosity can be related exponentially with the weight average molecular weight by the 3.4 power. Since literature data are scarce, attempts were made to extend the range by mixing polymers. This led to the complication of dispersity both on a molecular scale and on a macroscopic level. The latter point is particularly important for PVC studies since the polymers are frequently blended with materials having different viscosities.     

Miscibility behavior of blend of polyesteramides of linseed oil and dehydrated castor oil with poly(methacrylic acid)

Blending of two polymers in solution is a simple and cost‐effective technique to improve upon the physical and mechanical properties of the component polymers through synergism. To obtain maximum synergy in their properties, the component polymers should be miscible with each other on molecular scale. Polymer blends of complex physicomechanical properties are being actively investigated. Poly(methacrylic acid) (PMAA), a commercial polymer, yields transparent, hard, brittle, and water‐sensitive films. It has been blended with natural polymers like dextran, collagen, and gelatin to obtain films with improved physical and mechanical characteristics. Polyesteramides, which are easily synthesized from vegetable seeds oil, a sustainable resource, have found application in surface coatings. These oligomeric products do not make free standing films in the ambient condition. The polyesteramides from vegetable seeds oil can be used to obtain blend with PMMA of improved mechanical and water absorption properties. In this study, linseed oil polyesteramide (LOPEA) and dehydrated castor oil polyesteramide (DCPEA), the source oils with different unsaturation in their fatty acid chains, were blended with PMAA through mixing in solution in the ratio DCPEA/LOPEA: PMAA as 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, and 20/80. In the first instance, the miscibility of the two components was investigated in solution by viscosity and ultrasonic measurements and in solid phase through differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Moisture absorption by the blend was also studied. DCPEA and LOPEA show immiscibility with PMAA in solution phase while LOPEA with more unsaturation in the fatty acid chain of the oil was found more immiscible than DCPEA. DCPEA shows a narrow miscibility window in the solid phase while LOPEA was found immiscible with PMAA in the solid phase too. Uptake of moisture was found to be markedly reduced in the blends of DCPEA/LOPEA with PMAA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1367–1374, 2007:     

The effect of developing solvents on lipid class quantification in chromarod thin layer chromatography/flame ionization detection

Undeveloped lipids on Chromarods give peaks of variable shape and of variable area when scanned through the flame ionization detector (FID). With a brief exposure to developing solvents of suitable polarity, it is possible to produce sharp peaks of less variable area without appreciably moving peak axes. Longer developments or developments in more polar solvent systems result in broader-based peaks of lower area. These observations, based on many analyses of a triglyceride and of a ketone, suggest that the FID response of lipids can be modified according to their distribution around or along Chromarods.     

A Continuous process for the dehydration of castor oil

Summary A process for dehydrating castor oil continuously has been presented. The method consists essentially of exposing the oil in a thin film under the vacuum to temperatures between 310° and 350°C. for short periods of time in the presence of a dilute sulfuric acid catalyst. The relationship between various operational conditions and the physical constants of the oil produced has been determined. In addition, the oils were compared with several representative commercial oils.     

Analytical fractionation of complex lipid mixtures: DEAE cellulose column chromatography combined with quantitative thin layer chromatography

A quantitative chromatographic procedure for the fractionation of complex lipid mixtures is described. The method utilizes diethylaminoethyl (DEAE) cellulose column chromatography followed by thin layer chromatography (TLC). Spots produced in TLC are charred with sulfuric acid-potassium dichromate and heat and are then measured by quantitative densitometry. Results obtained with beef brain and beef heart mitochondrial lipids are presented, and the close correspondence between column isolation procedures and the new procedure is demonstrated. Methods utilizing only column chromatography, column chromatography and TLC, and one- and two-dimensional TLC without column chromatography are compared.