The pigments of crude cottonseed oils. II. Nitrogen-containing pigments derived from Gossypol

Summary Dark, crude cottonseed oil has been shown to contain a mixture of ninhydrin-sensitive substances combined with gossypol. Phenylalanine, aspartic acid, and glycine have been obtained by acid hydrolysis of the addition compound, followed by paper chromatography of the hydrolysate. The presence of other amino acids was indicated, but their identification could not be established with certainty; proline and hydroxyproline were apparently absent. The possibility that part of the color of dark, crude oils arises from gossypol-α-amino acid interaction is discussed. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Ethyl Acetate/2‐Butanol as Effective Green Chromatography Solvent for Coexisting Anionic Surfactants

Thin layer chromatography has been used for the analysis of anionic surfactants, which are common ingredients of personal care and cleaning products. From the environmental and human health points of view, emphasis has been placed on the use of safer solvents in analytical and synthetic chemical processes. In the present study, we have used 2‐butanol and ethyl acetate as a green mobile phase in combination with silica gel G as a stationary phase for the separation and identification of dodecylbenzene sulfonic acid, N‐lauroylsarcosine sodium salt, sodium lauryl sulfate, and dioctyl sodium sulfosuccinate. The separation pattern has been presented as a densitogram. To examine the separation efficiency of the proposed thin layer chromatographic system, chromatographic parameters for separations have been calculated. To examine the effect of nature of alcohol on the mobility of surfactants, 2‐butanol was substituted in the mobile phase (M₉) with other alcohols. Mobility trends of the separated surfactants have been examined in the presence of foreign organic and inorganic substances as impurities. The limits of detection for the separated surfactants have been determined. The proposed method has been successfully applied for the identification of surfactants in commercial products.     

A fast method to assess the composition of a polyolefin: An application to compliance testing of food contact materials

For plastics materials intended to be in contact with food, recent EU regulations, 72/2002/EC and 1935/2004/EC, enforce the assessment of the migration of 502 substances of the 932 positively listed substances. As mathematical modeling has been proposed to overcome such considerable effort in particular by providing maximum acceptable concentrations in the formulation, the compliance testing problem is efficiently reduced to the identification of substances and to their extent in initial materials. This work examines a fast identification and quantification procedure based on a semisupervised deconvolution procedure of FTIR spectra of polymer extracts in dichloromethane. The inversion procedure was implemented as a Tikhonov least‐square problem and designed to work on large and open dictionary of substances by combining both spectra of reference additives and normalized responses of typical chemical functions. The sparsity of the overall solution was fulfilled with non‐negativity constraints, while traces were detected by an iterative reweighting and stochastic resonance. The whole methodology was calibrated onto 21 typical additives of polyolefins and satisfactory tested on numerical examples and on extracts of processed films in high‐density polyethylene including up to eight unknown compounds. Maps of possible confusions and biases were generated for all tested substances. The mass balance laws for molecules belonging to similar classes of additives were particularly highlighted. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Identification of rutin and isoquercitrin in cottonseed

The flavonol glycosides, rutin and isoquercitrin, have been separated from crushed, delinted cottonseed (kernel and hull) by extensive use of paper chromatography. The identification of these flavonoid pigments has been achieved through paper chromatography, ultraviolet and infrared spectrophotometry, and qualitative and quantitative analysis of their hydrolysis products. Details of the separation and identification have been described.     

Biodegradation of montmorillonite filled oxo‐biodegradable polyethylene

Oxo‐biodegradation of polyethylene has been well studied with different pro‐oxidants and it has been shown that pro‐oxidants have limited role in the oxidation of polyethylene and do not have any role in microbial growth. However, in few recent studies, montmorillonite clay has been reported to promote the growth of microbes by keeping the pH of the environment at levels conducive to growth. In an attempt to improve the overall oxo‐biodegradation of polyethylene, montmorillonite nanoclay has been used in this study along with a pro‐oxidant. Film samples of oxo‐biodegradable polyethylene (OPE) and oxo‐biodegradable polyethylene nanocomposite (OPENac) were subjected to abiotic oxidation followed by microbial degradation using microorganism Pseudomonas aeruginosa. The progress of degradation was followed by monitoring the chemical changes of the samples using high‐temperature gel permeation chromatography (GPC) and infrared spectroscopy (FTIR). The growth of bacteria on the surface of the polymer was monitored using environmental scanning electron microscopy. GPC data and FTIR results have shown that the abiotic oxidation of polyethylene is influenced significantly by the pro‐oxidant but not by nanoclay. But, the changes in molecular weight distribution and FTIR spectra for the biodegraded samples indicate that the growth rate of P. aeruginosa on OPENac is significantly greater than that on OPE. It indicates that nanoclay, by providing a favourable environment, helps in the growth of the microorganism and its utilisation of the polymer surface and the bulk of the polymer volume. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Quantitative determination of polyethylene glycols in nonionic surfactants by high pressure liquid chromatography

A method employing high pressure liquid chromatography has been developed for the quantitative determination of polyethylene glycols in ethoxylated fatty alcohols and alkylphenols. This technique overcomes many of the limitations encountered in previously-reported methods. The polyethylene glycols are separated from the ethoxylated product and other sample components using a 65/35 acetonitrile/water mobile phase and a Bondapak C₁₈/Corasil reversephase column system. The response factor of the differential refractometer detector is determined using Carbowax standards of appropriate molecular weights. The molecular weight of the polyethylene glycols in each sample is approximated using thin layer chromatography prior to the high pressure liquid chromatography calibration and analysis. The precision of this method for the determination of polyethylene glycols is ± 4% relative or better, and the recovery of added polyethylene glycols is quantitative. Application of this method to a wide variety of commercial ethoxylated fatty alcohols and alkylphenols is presented. Presented at the Meeting of the American Oil Chemists’ Society, April 1976, New Orleans.     

Analysis of cyclopropenoid and cyclopropanoid acids in fats and oils

The analysis of cyclopropenoid acids may be considered, from a historical standpoint, to have started with the discovery of the Halphen test. Although this test as orginally conceived was utilized as a means of detecting adulteration of premium edible oils with cottonseed oil, it has since been shown to be a characteristic test for cyclopropenoid fatty acids and has been adapted with various modifications as a quantitative colorimetric test for these substances. More recently, spectrophotometric methods particularly in the IR region have been applied to the analysis of these substances. The 9.8 μ band, characteristic of the cyclopropane, and the 9.91 μ band, characteristic of the cyclopropene group, as well as the 11.0 μ band, characteristic of some of the noncyclic degradation derivatives, have been utilized. Gasliquid chromatography (GLC) has been applied to the methyl esters of cyclopropanoid and hydrogenated cyclopropenoid acids. The reactivity of the cyclopropene ring toward hydrohalogens has been the basis of several analytical methods developed for use with cyclopropene acid-containing oils. Both aqueous and nonaqueous solutions of hydrohalogens have been employed. The hydrohalogenation methods are the most precise methods currently available for these analyses but only GLC has the inherent potential of identifying the specific cyclopropenoid or cyclopropenoids involved. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Identification of some of the polysilicate components of trimethylsilylated cement paste

Trimethylsilyl derivatives from polymerised silicate anions in an eight-year-old cement paste have been fractionated by high-pressure liquid chromatography (hplc) and the fractions examined by thin layer chromatography, mass spectrometry and infrared spectrometry. The hplc separates linear from cyclic species. The major low molecular weight silicate anion in the C-S-H larger than dimer appears to be the linear pentamer. The presence in small quantity, of both linear tetramer and cyclic pentamer has been confirmed and the identification of the two high-temperature gas-liquid chromatography peaks with those species is supported.     

Thermodynamic and structural properties of acrylonitrile–butadiene rubber/polyethylene blends

Thermodynamics of interaction, adhesive properties, and the structure of acrylonitrile-butadine rubber/low density polyethylene blends have been investigated. Enthalpy and entropy components of interaction parameters supporting an incompatibility of studied systems and a possibility of highly organized structure formation on the phase interface were determined by inversion gas chromatography. The formation of highly organized structures on the interface is made possible by a local diffusion of polybutadiene fragments into polyethylene phase. That is why acrylonitrile microblocks are oriented. By this manner adhesion between rubber and polyethylene phase is enforced and simultaneously a number of morphological changes take place.     

Chromatographic analysis of sucrose esters of long chain fatty acids

The procedure of the quantitative analysis of the components of sucrose ester products is described. By thin-layer chromatography, sucrose ester products have been separated into their components: mono-,di-,tri-, and higher esters. The individual components have been extracted from the plate and determined colorimetrically by using anthrone reagent. Standard substances of monoesters, diesters and triesters, which have been synthesized from gas-chromatographically pure methyl esters of fatty acids, have been isolated by column chromatography and identified by elemental analysis, colorimetric determination and N.M.R. determination.     

Separation and identification of eugenol in ethanol extract of cloves by reversed-phase high-performance liquid chromatography

A method has been developed for the separation and identification of eugenol in the alcohol extract of cloves directly without having to previously separate other components. Extraction of eugenol with alcohol is followed by analysis with high-performance liquid chromatography. Separation by reversed-phase chromatography on low-polarity μBondapak C₁₈ was achieved with isocratic elution. Tentative identification is based on chromatographic appearance of a peak with retention time 5.54 min for pure standard reference eugenol. The identification of eugenol was confirmed by gas chromatography/mass spectrometry analysis.     

Components of the hardening flavor present in hardened linseed oil and soybean oil

The characteristic hardening flavor which develops in hardened linseed and soybean oils during storage has been coned from hardened linseed oil by stripping with nitrogen. After separating the volatile substances by adsorption chromatography on silica, the fraction containing the hardening flavor has been converted into 2,4-dinitrophenylhydrazones (DNPHs) and separated by means of partition chromatography. On regeneration of the fractions of DNPSs obtained, the characteristic hardening flavor was observed in one specific band. Both by hydrogenation and by oxidation of the free carbonyl the carrier of the flavor was found to be an unsaturated aldehyde; however, not of the α-β unsaturated type. Further separation of the regenerated carbonyls by means of gas-liquid chromatography (GLC) points to a C₉-aldehyde. After synthesis of the 4-,5- and 6-cis- andtrans-nonenals, comparison made it probable that the carrier of the hardening flavor is a mixture of 6-cis and 6-trans-nonenal, the latter of which has the greatest share in the hardening flavor. In order to confirm the location of the double bond in the carrier of the hardening flavor a recent isolation technique was applied. The volatile substances from hardened linseed oil were first separated via GLC. After conversion of the carbonyls in question into their DNPHs, the latter have been separated by means of thin-layer chromatography (TLC). By means of IR-analysis and oxidation with osmium tetroxide of the pure derivative, the principal carrier of the hardening flavor has been identified as 6-trans-nonenal.     

Degradation of unstabilized medium-density polyethylene pipes in hot-water applications

Pipes of an unstabilized medium-density polyethylene have been pressure tested with internal stagnant water and moderately circulating air as the external medium at temperatures ranging from 70 to 105°C and changes in molecular structure and crystallinity have been studied. The stage III (fracture induced by thermal oxidation) life of the unstabilized polyethylene pipes was less than 12% of the life of the corresponding stabilized polyethylene pipes. Infrared spectroscopy and size exclusion chromatography showed an earlier and more extensive increase in the quantities of oxidation end-products and a more pronounced decrease in molar mass of the outer-wall-material than of the inner-wall-material of the pipe. Mass crystallinity, measured by differential scanning calorimetry, increased on an average by a quantity corresponding to 45 methylene groups per chain scission event. The life of the unstabilized pipe was divided into an induction period during which no detectable thermal oxidation occurred and a subsequent polymer degradation period. The induction period exhibited an Arrhenius-temperature-dependence with an activation energy of 75 kJ mol^?1.     

Effect of surface acidity of activated carbons on their characteristics of adsorption from the vapour phase—comparison of retention time for carbons used as adsorbents for gas chromatography

Seventeen kinds of activated carbons of different surface acidity and of known pore-structure were used as adsorbents for gas chromatography. The retention time of various kinds of substrates was determined for each carbon at different temperatures. It was found that surface acidity of carbons has a marked effect on increasing the retention time for polar substances while showing no effect for non-polar substances. Retention times varied with temperature which suggested, when the effect of surface acidity is taken into account, that the pores which were effective for the Chromatographic adsorption have been determined by the temperature. The heat of adsorption calculated on the basis of the retention times observed at different temperatures showed an inverse correlation with dielectric constant of the adsorbates.     

Dielectric and Chromatographic Characterization of Polyethylene Glycols as Stationary Phases

Abstract

Three types of polyethylene glycols of different molecular weights namely, 600, 4000 and 20000, were evaluated as liquid stationary phases in gas liquid chromatography. Thus, the retention mechanism for the studied polymer stationary phases, 15% by weight on chromosorb PAW and their thermodynamic parameters have been investigated via inverse gas chromatography. The effect of polymer molecular weight on their efficiency as liquid stationary phases for the gas chromatographic separation of different types of hydrocarbons is also studied. The dielectric constant of dilute solutions for the studied polymers as dissolved in solvent chloroform was studied corresponding to their polarities. Two different modes of clusters were determined due to the solute-solute and solute-solvent interaction through hydrogen bonds.

All studied polymers have higher performance for separation of cyclic and aromatic compounds. Good chromatographic separation of n-alcohols is obtained toward polyethylene glycol (PEG20000) of relatively higher molecular weight. The saturated hydrocarbons can be separated very efficiently using low molecular weight polyethylene glycol (PEG600).     

Purification of biomolecules combining ATPS and membrane chromatography

Upstream processes for production of therapeutic proteins have been innovated and fermentation processes have been adopted for the use of recombinant microorganisms with high expression, but the downstream process is still the bottleneck in the biotechnological manufacturing process. A combined process consisting of aqueous two phase extraction (ATPE) and membrane chromatography is suggested to debottleneck downstream processing. ATPE has a large capacity, but the yield of the target product is from 74% to 97%. For this reason the product of ATPE waste stream is captured by membrane chromatography. In this work the binding capacity for the protein on protein A, ion exchange and hydrophobic exchange membrane chromatography was investigated experimentally with different concentration of polyethylene glycol (PEG), salt and protein. Protein A membrane was loaded with solutions resembling waste streams of ATPE for purifying IgG. For ion exchange and hydrophobic interaction membrane chromatography, the membrane was loaded with bovine serum albumin (BSA). PEG shows no significant effect on stability and capacity of membrane process. Even for small amount of BSA/IgG and high salt concentrations membrane adsorption is applicable. In this work it is demonstrated experimentally that a total product recovery of 99.9% for the purification of monoclonal antibody is possible.     

离子色谱在乙二醛电氧化过程中的应用

基于离子色谱原理,成功地研发出一种适用于乙二醛电氧化过程主要物种快速检测的新技术。研究表明,该技术不仅具有设备简便,检测快速灵敏和选择性高等优势,而且还能实现同时测定多种组分的目的。检测灵敏度小于0 5mg/L,保留时间、峰高、峰面积的变异系数均小于2%;对各物种回收率的检测结果为97%～103%。离子色谱电导检测技术的成功研发为乙二醛电氧化过程物种的实时、快速检测提供了便捷的分析手段,这对电合成体系的生产指导和过程评价具有重要意义。     

REVIEW OF ZEOLITES AS DEODORANTS FOR POLYETHYLENE RESINS USED IN FOOD PACKAGING APPLICATIONS

The formation of odoriphores in polyethylene (PE) is of concern to industries involved in the packaging of items such as foodstuffs and pharmaceuticals that are sensitive to organoleptic contamination. Hitherto, traditional strategies such as increasing the level of antioxidant, reducing contact between the resin and oxygen during processing, optimizing processing conditions, and reducing substances that promote degradation during polymerization, have all been used to reduce odorous volatile organic compounds to some extent. Lately, there has been an interest in zeolites for this purpose. This article reviews the use of zeolites as deodorants in PE resins. The use of zeolites as adsorbents of ripening and degradation products and as antimicrobial agents in food packaging applications is also discussed. In addition, the effects zeolites have on the physico-mechanical properties of PE are considered.     

Umweltverhalten und Toxikologie der Wachse

Environmental Behaviour and Toxicology of Waxes Plant and animal waxes are chemically relatively stable nontoxic substances and are used by humans since ages. In the nature waxes have protective function against environmental influences. This protective action is possible due to great resistance of the waxes towards environment, which also means low biological degradability. Obviously, waxes are undigestible and non-toxic in human and animal organism. Partially synthesized waxes based on montana wax, a plant fossil wax, have a structure similar to natural waxes, and therefore they resemble natural waxes with regard to environmental behaviour and are fully harmless from toxicological viewpoint. Also fully synthetic waxes, such as polyethylene waxes and polyethylene oxide waxes have, according to results obtained so far, no undesirable effects on environment. Waxes have been approved in foods worldwide, obviously due to their favorable toxicological properties.