Chlorobutanol Research Articles

Preventative Effect of Topical Rebamipide Against Corneal Epithelium Disorders Caused by Diclofenac Sodium.

Purpose: This study aimed to investigate the relationship between diclofenac sodium ophthalmic solution (DFNa) and corneal epithelial cell damage and to evaluate the preventive effect of rebamipide (RBM) on it. Methods: DFNa, DFNa/preservative-free (PF), or 0.5% chlorobutanol (CB) solution was instilled into the conjunctival sac of a normal rabbit eye, and corneal resistance measurement (using a corneal resistance device [CRD]) was performed 120 min after the end of instillation. Then, fluorescent staining (FL), corneal tissue staining (hematoxylin and eosin [H&E]), and immunostaining (zona occlusion-1) were performed (RBM-untreated group). However, RBM was instilled into the eyes of another group of normal rabbits, followed by each of the solutions; 120 min after the end of instillation, all evaluations were performed for this group (RBM treatment group). Results: Using the CRD method, in the RBM-untreated group, corneal resistance (CR; %) was found to be significantly reduced in DFNa (79.9 ± 19.4%), DFNa/PF (89.1 ± 17.3%), and 0.5% CB (83.8 ± 10.6%). In addition, DFNa and 0.5% CB solutions showed positive staining in the FL staining method. In the H&E staining method, some clear voids were observed in the outermost layer of the cornea using DFNa and 0.5% CB solutions. However, corneal epithelial damage was suppressed in the RBM treatment group. ZO-1 immunostaining in DFNa and 0.5% CB solutions revealed discontinuous localization of ZO-1 at the cell periphery. Conclusions: RBM eye drops were effective in preventing corneal epithelial damage caused by DFNa eye drops, and CB was considered to be the main causative agent of this damage.

Oliveramine: An Isolated Alkaloid from Fagraea fragrans (Tembesu) Bark

This paper described the progress of phytochemical, especially alkaloids, work on Fagraea fragrans species (tembesu), Loganiaceae. A dimeric-pyridine alkaloid with molecular formula C20H20O4N2 has been successfully isolated from diethyl ether extracts from this plant’s barks. The alkaloid was explored from diethyl ether extracts using sulphuric acid (2%), then basified with ammonium hydroxide (25%) until the solution had a pH of 10.5. The later solution was extracted again with chloroform. The alkaloid residue was subjected to column chromatography and eluted with 10% acetone in chloroform. The chemical structure of the isolated dimeric-pyridine alkaloid was determined by LCMS/MS, 13C-NMR, and 1H-NMR spectroscopies. As a result, the isolated dimeric-pyridine alkaloid was closely similar to the oliveramine alkaloid, and this is also the first report about oliveramine from Fagraea fragrans (F. Fragrans).

In Vivo Evaluation of the Oral Toxicity of the Chlorobutanol.

Chlorobutanol (CB) is used as a preservative in cosmetics and has antibacterial activity. This study investigated the single- and repeated-dose 28-day oral toxicity of a CB solvent in Sprague Dawley (SD) rats. For the single-dose oral toxicity study, a dose of 62.5, 125, or 250 mg per kg of body weight (mg/kg b.w.) of CB was given once orally via gavage. For the repeated-dose 28-day toxicity study, the high dose was set as 100 mg/kg b.w./day, and the middle, middle-low, and low doses were set to 50, 25, and 12.5 mg/kg b.w./day, respectively. Body weight was not significantly changed in the repeated-dose toxicity study. Relative liver and kidney weights were significantly increased in both sexes of the 100 mg/kg b.w./day treatment group. However, there were histopathological changes in liver and kidney for females and males, respectively. These data suggested that the approximate lethal dose (ALD) of CB was over 250 mg/kg b.w./day in the single-dose study, and the no adverse effect level (NOAEL) for CB was over 50 and 12.5 mg/kg b.w./day for female and male rats in the repeated-dose toxicity study.

Standardization and validation of a high-performance thin-layer chromatography method for the quantification of aflatoxin B1 and its application in surveillance of contamination level in marketed food commodities from the Mumbai region

Aflatoxin B1 (AFB1) is a natural carcinogenic contaminant of agricultural product regulated at parts per billion (ppb) level; therefore, a validated method for the analysis of AFB1 is extremely important. In this study, a high-performance thin-layer chromatography (HPTLC) method was standardized and validated with respect to linearity, sensitivity, precision, and accuracy for the quantification of AFB1. Three extraction techniques using different solvent systems, namely QuEChERS (quick, easy, cheap, effective, rugged and safe) method, Contaminants Branch method and Best Foods method were evaluated for AFB1 extraction efficiency in food commodities, wherein QuEChERS method using acetonitrile‒methanol (40:60, V/V) gave maximum recovery of AFB1 in all commodities. Maximum AFB1 was recovered in dried chilli sample (89.98%), whereas the least recovery was obtained in wheat sample (68.20%). The optimized HPTLC method with chloroform‒acetone (9:1, V/V) as the mobile phase showed a compact AFB1 band at RF value of 0.36 ± 0.02. The linear regression analysis of AFB1 showed good linearity over 10, 20, 40, 60, 80, 100, 120 ng/spot with a regression value of 0.9923 and %RSD less than 1. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.133 ng/band and 3.434 ng/band, respectively. The optimized HPTLC method was further used to assess the AFB1 content in marketed samples of groundnut, corn, rice, wheat and dried chillies from the Mumbai region and it was found that 8 groundnut samples, 5 corn samples, 5 wheat samples, and 7 chilli samples out of 20 each had AFB1 concentration above Indian permissible regulatory limit of 30 ppb.

Азозамещенные этоксиакридина – реагент для экстракционно-фотометрического определения индия(III)

The associates of bromo-indate with azo-substituted ethoxyacridine have been studied by spectrophoto-metric method. It has been found that the associates are well extracted with a mixture of chloroform acetone (4:1). The optimum volume of aqueous and organic phase is equal to 5 ml. The molar ratio of the components in the extractable compounds was studied by the methods of isomolar series, equilibrium shift and a straight line. It was found that bromo-indate associated with azo-ethoxyacridines (AE) in a ratio of 1:1. Study of the effect of foreign ions on the accuracy of the determination of indium with azo-substituted ethoxyacridine showed that the number of ions does not interfere (in parentheses are multiple relationships to indium ions); CdII (1200), NH4+ (4000), Zn2+ (1500), CoII (1100), NiII (1050), CuII (500), FeII (4000), PbII (250), Nb (250), TaV (270), Al3+ (2000), ReVII (140), B3+ (410), C2O42- (1900), CH3COO- (1300), ascorbic acid (270), citrate ion (3500), tartrates (4000), EDTA (3700). Number of ions interfered the determination: TlIII (1), FeIII (1), Ga3+ (1), HgII (1), SbV (1), AuIII (1), thiourea (4). It was studied formation and extraction of associates of bromo-indate with AEADPA (2-ethoxy-6-(4-N,N-dipropylphenylazo)-9-aminoacridine) and AEADEA (2-ethoxy-6-(N,N-ethylphenylazo)-9-aminoacridine). The maxima of light absorption of bromo-indate with AEADPA is observed at 530 nm, and the AEADEA at 515 nm. The physico-chemical and analytical characteristics of the azo-substituted ethoxyacridines and their ionic associates with indium bromide acid complexes (λmax ε, βkD, D, R%) were determined. It was shown that bromo-indate compounds with azo-substituted ethoxyacridines are ionic associates, the molar ratios of the components in which are: [İn III] : [Br -] : R + = 1:4:1. Highly efficient extraction-photometric methods have been developed for the determination of trace amounts of indium in various objects.

TLC-Densitometric Determination of Five Coxibs in Pharmaceutical Preparations

A class of drugs called coxibs (COX-2 inhibitors) were created to help relieve pain and inflammation of osteoarthritis and rheumatoid arthritis with the lowest amount of side effects possible. The presented paper describes a new developed, optimized and validated thin layer chromatographic (TLC)-densitometric procedure for the simultaneous assay of five coxibs: celecoxib, etoricoxib, firecoxib, rofecoxib and cimicoxib. Chromatographic separation was conducted on HPTLC F254 silica gel chromatographic plates as a stationary phase using chloroform–acetone–toluene (12:5:2, v/v/v) as a mobile phase. Densitometric detection was carried out at two wavelengths of 254 and 290 nm. The method was tested according to ICH guidelines for linearity, recovery and specificity. The presented method was linear in a wide range of concentrations for all analyzed compounds, with correlation coefficients greater than 0.99. The method is specific, precise (%RSD < 1) and accurate (more than 95%, %RSD < 2). Low-cost, simple and rapid, it can be used in laboratories for drug monitoring and quality control.

Thermodynamic and Topological Analysis of Phase Diagrams of Quaternary Systems with Internal Singular Points

A review of the literature published in Russia and abroad on the experimental studies of phase equilibria, methods for analyzing and predicting phase diagram structures, and simulating problems of the vapor–liquid equilibrium (VLE) of quaternary systems containing internal singular points is presented. A complete set of parameters that adequately describe the liquid–vapor and liquid–liquid equilibrium is obtained for the following four systems: acetone–chloroform–ethanol–water, acetone–chloroform–propanol-2–water, chloroform–ethanol–cyclohexane–water, and ethyl acetate–methyl ethyl ketone–cyclohexane–propanol-2. The methodology for determining the structure of the VLE diagram and predicting the presence of an internal azeotrope in the systems under study and in a model system that contains binary azeotropes and a quaternary azeotrope is illustrated. Possible ways for evolutionary changes in the structure of the VLE diagram with a variation in the pressure are shown, and the Poincare indices of boundary single azeotropes and a double tangential azeotrope are determined.

DEVELOPMENT OF A METHOD FOR HYDROLYTIC CLEAVAGE OF MOLECULES SAPONINS – DERIVATIVES OF QUILLAJA ACID

The possibility of hydrolytic decomposition of glycosides soap tree Qullaja. The conditions for the complete hydrolysis of saponins: a mixture of hydrochloric acid, water, ethanol in a ratio of 4 :7.35 : 6.65, heating time – at least 6 hours. The composition of the carbohydrate part of saponins was established – xylose, glucuronic acid, galactose, arabinose were identified in all hydrolysates. The analysis of the obtained fraction of aglycone – willieboy acid physico-chemical methods. Based on the calculation results of chromatographic characteristics (mobility, number and height of theoretical plates), a system for elution of aglycone of the following composition is recommended: petroleum ether–chloroform–acetone (20 : 20 : 5). By the method of potentiometric titration in a non-aqueous solvent medium, the percentage of aglycone in the selected fractions was determined-88.23%. A comparative study of the aqueous solution of aglycone and saponins by UV spectrophotometry. A decrease in the intensity of absorption bands in the 230, 290 nm region responsible for the absorption of carbonyl structures is shown. Analyzed the IR spectra of saponins and willieboy acid identified bands assigned to the vibrations of functional groups of the aglycone and the carbohydrate residue.

Phenolic Compounds of Picea obovata Ledeb. Bark

Chemical composition of a phenolic complex of the Siberian spruce bark (Picea obovata Ledeb.) and a structure of oligomeric phenolic compounds composing the bark were studied. The samples of the spruce bark were collected in the vicinity of Lake Baikal in September 2015. Extractive substances were recovered from the crushed bark by extraction with ethyl acetate at the boiling point of the solvent for 4 h. The resinous substances were extracted from the ethyl acetate extracts with hexane by infusion for three days. The samples of bark after extraction with ethyl acetate were dried from solvent residues, and then water-soluble substances were isolated by extraction with distilled water at 90°C for 4 h. The yields of the extractive substances extracted with ethyl acetate and water from the spruce bark on absolutely dry matter were 3.4 and 6.9%, respectively. The relative percentage content of phenolic compounds in the ethyl acetate extract of the spruce bark was 42.4%. The ethyl acetate extract of a spruce bark, pretreated with hexane, was fractionated on a silica gel column using a mixture of chloroform–acetone as the eluent with an increase in the fraction of the latter (from 0 to 100%). The content of monomeric and oligomeric, polymeric phenolic compounds in the extract was determined. Based on the data of 1Н and 13C NMR spectroscopy, it was established that the flavonoid dihydroquercetin and stilbene glycosides isorhapontin and astringin were the main monomeric phenolic extractive substances of Siberian spruce bark. It was shown that the structure of oligomeric phenolic compounds of the spruce bark includes structural fragments of stilbene glycosides, mainly monomeric blocks with the structure of isorhapontin and astringin.

Atomistic Insights into Hydrogen-Bonding-Driven Competitive Adsorption of Acetone–Chloroform Binary Mixtures

The competitive adsorption of molecules on a surface has both beneficial and detrimental effects for technological applications, such as chromatography (material separation) and protein adsorption ...

Enhanced separation of maximum boiling azeotropic mixtures with extractive heterogeneous-azeotropic distillation

In the separation industry the extractive heterogeneous-azeotropic distillation (EHAD) is a new and powerful innovation, that is capable of making the separation of highly non-ideal mixtures feasible and economical. In the last years there has been much attention paid to the separation of the minimum boiling homogeneous azeotropes. Although maximum boiling azeotropes are fewer in numbers than the minimum boiling ones but their separation is more complicated but it could be solved with the EHAD, too. Since EHAD is not limited to the separation of minimum boiling azeotropes, the separation of the maximum boiling azeotropes is studied in this work. Our work is motivated by industrial problems because there are such maximum boiling azeotropes in the liquid wastes of the fine chemical industry. The separation of highly non-ideal Water–Acetone–Chloroform–Methanol and Water–Ethyl Acetate–Chloroform–Ethanol quaternary mixtures are investigated and optimized in professional flowsheet simulator environment. Total Annual Costs are also determined. The purity requirement is 99.5 m/m% for Chloroform and the bottom product should be as clear as possible in water so that less liquid organic waste has to be incinerated. It is also an important merit of the EHAD that the chemicals in the distillate can be usually reused supporting sustainability. Different solutions for the separations supplemented with heat integration are examined. On the basis of the computer simulations and the experimental verification it can be concluded, the first time on the literature, that the separation efficiency of EHAD is superior also for the separation of the maximum boiling azeotrope mixtures.

PHARMACOGNOSTICAL AND PHYSICOCHEMICAL ANALYSIS OF TODDALIA ASIATICA (L.) LAM. RUTACEAE

Objective: To characterize macroscopical and microscopical features of the leaf and stem of Toddalia asiatica (L.) Lam. RUTACEAE. Explore and establish the micro-morphology and quality control methods for this plant.Methods: leaves and stem of Toddalia asiatica (L.) Lam. were collected for Pharmacognostic studies involving macros, microscopic evaluation and physicochemical parameters analysis like Ash value, Moisture content, Fluorescence analysis and phytochemicals.Results: The leaf even and smooth on the adaxial side and highly undulate and densely hairy on the abaxial side. The midrib is very thick projecting much below the lower side of the leaf. The midrib is slightly revised above the adaxial side. It is thick and semicircular on the abaxial side. It is 950 µm thick and 900 µm wide. The lateral vein hangs from the abaxial surface of the lamina. It is thick and prominent. There is no distinct differentiation of palisade and spongy mesophyll tissue. The lamina is 100 µm thick. In the region of lateral veins, it is 160 µm thick. Calcium oxalate crystals are fairly abundant in the secondary xylem parenchyma cells of the stem. Prismatic crystals also sparsly seen in the parenchyma cells outside the gelatinous fibre. The powder was also treated with different chemical reagents and changes in colour were studied in ordinary light and UV light. These fluorescence characters were determined according to the methods of Chase and Pratt. The total moisture content of the Toddalia asiatica was 46%. The total ash content of the whole plant was found 96%, the acid insoluble ash content of the whole plant was found 5%, the water-soluble ash content of the whole plant was found 2%, and the sulphated ash content of the whole plant was found 85%. The extractive values obtained from different solvents were found in the Toddalia asiatica among all the extracts chloroform showed the highest percentage (81%) followed by Ethanol (45%) and Benzene (44%). The distribution of different phytochemical constitutes in ethanol, benzene, chloroform acetone, petroleum ether and water of whole plant powder was evaluated qualitatively. The phytochemical such as carbohydrates, saponins, flavonoid, alkaloids, cardiac glycosides, phenols, coumarins, and steroids have been confirmed in the all the above extracts of the selected plant. Moreover, phytochemicals such as alkaloids, flavonoid, cardiac glycosides, courmarins, and steroids are also present in the sample and absence of, anthraquinone, steroid, terpenoid and fixed oil.Conclusion: The observations confirmed that Toddalia asiatica obvious Pharmacognostic characteristics, which will be useful towards providing a reliable basis for identification, purity, quality, and classification of the plant. Results shall pave a way in the standardization of the drug.

The Reaction of Poly(Vinyl Amine) with Acetone in Water

AbstractPoly(vinyl amine) (PVAm) reacts with acetone in aqueous solution. It generates imine and aminal moieties along the PVAm backbone. The molecular structure of acetone‐modified PVAm is confirmed by liquid 1H and 13C as well as solid state 13C NMR and ATR‐FTIR spectroscopies. Model compounds produced from 1,3‐diaminopropane with acetone in chloroform are used to assign the solid state 13C NMR signals of the modified polymer. Quantitative elemental analysis of acetone‐modified PVAm samples supports the analytical results. The mechanism of the imine and aminal formation is discussed with regard to the anomeric stabilization of the incipient hemiaminal intermediate. The rapid and unexpectedly favorable formation of PVAm acetone hemiaminal, acetone imine, and aminal formation has implications for the conduct of PVAm research and even the interpretation of prior published results. As acetone was often used in the past to precipitate waterborne PVAm derivatives, this finding has a severe impact on the interpretation of research results. The consequences and the revised interpretation of selected publications are discussed.

HPTLC-Densitometric Method for Determination of Ascorbic Acid, Paracetamol and Guaifenesin in Presence of Their Toxic Impurities.

Ascorbic acid (ASC), paracetamol (PAR) and guaifenesin (GUF) are co-formulated together as analgesic and expectorant effervescent powder. This work describes a selective stability indicating HPTLC-densitometric method which is the first developed stability indicating one for chromatographic separation of the three studied drugs in presence of paracetamol toxic impurity [4-aminophenol (4-AP)] and guaifenesin related substance [impurity, (guaiacol) (GUC)]. The chromatographic separation was carried out on HPTLC 60F254 plates using chloroform-acetone-trifluoroacetic acid (6.5:3.5:0.30, by volume) as a developing system with UV detection at 254 nm. Factors affecting chromatographic separation have been optimized and good separation was obtained between the studied components where (ASC Rf = 0.05, 4-AP Rf = 0.12, GUF Rf = 0.24, PAR Rf = 0.41 and GUC Rf = 0.56). Method validation has been performed according to ICH guidelines and linearity was achieved in the range of 0.4-2.4, 0.4-2.8 and 4-15 μg/band for ASC, PAR and GUF, respectively. In order to evaluate the developed method it was applied for determination of the cited drugs in G.C.Mol® effervescent powder and the obtained results were statistically compared with those obtained by applying the reported HPLC method using Student's t- and F-tests where no significant difference was observed. The developed method has the advantages over the reported HPLC one of being more sensitive and selective which permit its application in quality control analysis of the cited their in presence of drug impurities.

Self-Diffusion and Heteroassociation in an Acetone–Chloroform Mixture at 298 K

The self-diffusion coefficients of acetone and chloroform in a binary acetone–chloroform mixture at 298 K are determined via pulsed field gradient NMR spectroscopy. It is estimated that the hydrodynamic radii of the mixture’s components, calculated using the Stokes–Einstein equation, grow as the concentrations of the components fall. It is shown that such behavior of hydrodynamic radii is due to acetone–chloroform heteroassociation. The hydrodynamic radii of monomers and heteroassociates in a 1: 1 ratio are determined along with the constant of heteroassociation, using the proposed model of an associated solution.

Self-assembly morphology and packing structures depend on the ‘head’ of organic cations anchored on polyoxometalate anions in hybrids

Two organic-polyoxometalates (organic-POMs) hybrids were constructed by fan-shaped 1-methyl-3-[3, 4, 5-tris(octadecyloxy) benzyl]imidazolium salts (labelled as I–Cl) and triethyl-[3, 4, 5-tris (octadecyloxy) benzyl] ammonium salts (labelled as Q–Cl) and Keggin anions [SiW12O40]4− by electrostatic interaction. Self-assembled behaviours of two aggregates in organic solvent and solid state were investigated in detail by scanning electron microscopy, transmission electron microscopy and X-ray analysis. The mixed solution of chloroform–methanol or chloroform–acetone provided the stable environment for aggregates and aggregates showed a uniform micron size. X-ray analysis results showed that flower-like aggregates morphology of I4[SiW12O40] based on imidazole ring as ‘head’ in organic cations was formed by the stacking of multilamellar discs and kept the lamellar structure in solid state. Bulk thorn spheres appeared in Q4[SiW12O40] aggregates, which were formed by closely interspersed of lots flatted blocks with hexagonal structure characteristics in solid state. The comprehension for the self-assembly morphology and solid structure of organic-polyoxometalate hybrids would help us to use easily modified organic moiety and functional inorganic polyoxoanions as blocks to build novel and giant supramolecular architecture.

Antioxidant Activity of Lichen Parmotrema austrosinense and its Antimicrobial Effect on Selected Plant Pathogens

Parmotrema austrosinense(Zahlbr.) Hale is one of the lichens used as spices and also it has medicinal property. The goal of this investigation was to assess the antioxidant, reducing power, free radical scavenging and antiphyto pathogenic effect of P. austrosinense. Lichen sample was extracted with different solvents - benzene, methanol, chloroform and acetone. The benzene extract showed a strong antioxidant activity (5.665±0.0065) followed by chloroform extract (3.648±0.0029), acetone extract (2.770±0.0078) and methanol extract (2.430± 0.0046). The methanolic extract of lichen showed the highest reducing power followed by the acetone and nonpolar solvents like chloroform and benzene. Among the four solvents chosen, methanol extract of lichen showed the highest free radical scavenging activity followed by acetone, chloroform and benzene. The antimicrobial activity non-polar solvents like chloroform and benzene extract showed highest antimicrobial activity against three tested fungi (Fusarium oxysporum, Rhizoctonia solani, Sclerotium rolfsii) and bacterial plant pathogens(Bacillus sp.,Xanthomonas phaseoli and Erwinia chrysanthemi)followed by methanol and acetone extracts and streptomycin was used as a control antibiotic.

Effect of VLE uncertainties on the design of separation sequences by distillation – Study of the benzene–chloroform–acetone system

It is widely recognized by experts that the computer-based design of chemical processes depends strongly on the correlated thermodynamic and transport properties, and that the effect of the property uncertainties should be accounted for in the design. The most significant source of property uncertainties on process design comes from the correlations of mixture phase equilibrium. Many approaches to uncertainty analysis have been proposed, but uncertainty analysis is not a routine element of today's industrial practice, mainly because education and awareness are lacking, and the proposed methods are difficult to apply.In order to help rectify the situation, the author developed an intuitive and easy-to-apply phase-equilibrium (specifically, activity coefficient) perturbation method based upon treating the mixture, for the purpose of uncertainty perturbation, as a set of pseudobinaries described by the Margules equation. The approach was applied to two case studies – (1) a propylene-propane superfractionator for which small changes in correlated relative volatilities have a large effect on the design of the distillation column; and (2) a dehexanizer column that separates a mixture containing many close-boiling components – and demonstrated that the proposed methodology provides quantitative insight into the effect of property uncertainties, and helps to estimate the safety factors that should be imposed upon the design.In this paper the Margules perturbation method is applied to the “textbook” separation of an acetone–chloroform–benzene ternary mixture; this case study was proposed in 1996 by Westerberg and Wahnshafft, and was previously studied by Parodi and Campanella. The approach of Parodi and Campanella used different levels of data fitting to identify uncertainties, while the present methodology is to obtain the best fit of the data, and then apply uncertainties based upon estimated combined model uncertainties, which includes experimental uncertainties and any model inadequacies. The purpose of this paper is to further study whether the Margules approach to mixture uncertainty offers insight, and is a useful technique to perform uncertainty analysis.

Improved separation and analysis of glycolipids by Iatroscan thin-layer chromatography–flame ionization detection

We demonstrate improved power of Iatroscan thin layer chromatography/flame ionization detection (TLC–FID) technique for analysis of complex marine lipid mixture by developing protocol for the separation and analysis of glycolipids including sulfoquinovosyldiacylglycerols (SQDG), monogalactosyldiacylglycerols (MGDG) and digalactosyldiacylglycerols (DGDG). We have modified the common protocol used so far for the analysis of lipid classes by replacing the elution step which uses pure acetone for the elution of acetone mobile polar lipids, with the elution step containing chloroform–acetone (72:28, v:v) for separation of MGDG and DGDG. To separate SQDG from the complex lipid matrix we introduced solvent mixture acetone–chloroform–methanol–formic acid (33:33:33:0.6, v:v:v:v). Quantification of glycolipid classes was performed after calibration with glycolipid standards for the masses between 0.2 and 2.7–5.0μg. With this new protocol we have successfully separated three glycolipids from the complex particulate lipid mixture of the seawater samples. Such an approach extends the power of existing protocol for the analysis of lipids which altogether ensure detection and quantification of 18 lipid classes what was demonstrated on seawater samples. This enables to gain a very broad system overview of the particularly complex environments as are seas, oceans and freshwaters.

Systematic design of an extractive distillation for maximum‐boiling azeotropes with heavy entrainers

Extractive distillation is one of the most attractive approaches for separating azeotropic mixtures. Few contributions have been reported to design an extractive distillation for separating maximum‐boiling azeotropes and no systematic approaches for entrainer screening have been presented. A systematic approach to design of two‐column extractive distillation for separating azeotropes with heavy entrainers has been proposed. A thermodynamic feasibility analysis for azeotropes with potential heavy entrainers was first conducted. Then, five important properties are selected for entrainer evaluation. Fuzzy logic and develop membership functions to calculate attribute values of selected properties have been used. An overall indicator for entrainer evaluation is proposed and a ranking list is generated. Finally, the top five entrainers from the ranking list have been selected and use process optimization techniques to further evaluate selected entrainers and generate an optimal design. The capability of the proposed method is illustrated using the separation of acetone–chloroform azeotropes with five potential entrainers. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3898–3910, 2015