Proportions Of Acetone Research Articles

Fatty Acids and Volatile Flavor Components of Adipose Tissue from Local Tibetan Sheep in Qinghai with Dietary Supplementation of Palm Kernel Meal (PKM).

Substituting traditional protein feed with palm kernel meal (PKM) in the diet of Tibetan sheep can be a cost-effective feeding strategy. To determine the impact of PKM on flavor development in different adipose tissues of Tibetan sheep, subjects were fed with 15% and 18% of PKM, while the control group received no PKM. The fatty acids and volatile compounds in the samples were then analyzed by GC-MS and HS-GC-IMS. Adding PKM to the diet significantly increased the C12:0, C14:0, C16:0 and C18:1N9 content in adipose tissues compared with the control, and most of these were associated with flavor formation (p < 0.05). The flavor compounds in the adipose tissues predominantly consisted of alcohols, ketones, acids and aldehydes. In particular, including PKM in the diet increased the proportion of ketones but decreased the proportion of alcohols, acids and aldehydes in subcutaneous and tail fat. Specifically, the proportion of acetone, acetoin monomer, 2,3-butanedione, 2-butanone monomer, 2-methyl-2-propanol, 2-methyl-2-propanol and methyl acetate increased significantly in the subcutaneous and tail fat (p < 0.05), while that of ethanol, 1-propanol monomer, butanol monomer, acetic acid monomer and acetic acid monomer decreased. Intermuscular fat exhibited variable results, mainly because the addition of PKM resulted in higher proportions of alcohols, including ethanol, 1-propanol and butanol monomer, especially at 15% PKM. In summary, the addition of PKM improved the flavor of Tibetan sheep fat and increased the amount of favorable volatile flavor compounds. This study can serve as reference for understanding the effects of dietary PKM on the adipose tissue flavor profile of Tibetan sheep.

Solvent effect and Activation Parameters: A Kinetic Reaction of Ethyl Caprylate in Water-Acetone Media

The kinetic result of hydrolysis of Ethyl Caprlyate has been investigated at different composition of aqueous-organic solvent with Acetone (30-70% v/v) over the temperature range of 20 to 400c. The calculated result follows second order kinetics and is observed that the rate decreases with increasing proportion of Acetone. This behavior is attributed electrostatic nature that various solvent-solute interaction in reaction media. Linear plots of Logk against water concentration shows that equilibrium shifted from dense form to bulky form. Iso-kinetic temperature has been determined with the help of slopes of (ΔH*) versus (ΔS*). Thermodynamic parameter has been calculated with the help of Wynne-Jones and Eyring equation.

Characterization and evaluation of the photocatalytic activity of oxides based on TiO2 synthesized by hydrolysis controlled by the use of water/acetone mixtures

New photocatalysts based on TiO2 were synthesized and characterized. The synthesis involved the controlled hydrolysis of titanium tetraisopropoxide using water containing different proportions of acetone. X-ray diffraction analyses combined with Raman spectroscopy revealed crystalline oxides characterized by the coexistence of the anatase and brookite phases. The Rietveld refinement of diffractograms showed that the presence of acetone in the synthesis process influenced the composition of these crystalline phases, with the proportion of brookite growing from 13% to 22% with the addition of this solvent in the synthesis process. The BET isotherms revealed that these materials are mesoporous with surface area approximately 12% higher than that of the oxide prepared from hydrolysis using pure water. The photocatalytic potential of these oxides was evaluated by means degradation tests using the dyes Ponceau 4R and Reactive Red 120 as oxidizable substrates. The values achieved using the most efficient photocatalyst among the synthesized oxides were, respectively, 83% and 79% for mineralization, and 100% for discoloration of these dyes. This same oxide loaded with 0.5% of platinum and suspended in a 5:1 v/v water/methanol mixture, produced 56 mmol of gaseous hydrogen in 5 h of reaction, a specific hydrogen production rate of 138.5 mmol h−1g−1, a value 60% higher than that achieved using TiO2 P25 under similar conditions.

Influence of organic solvents in the extraction and purification of torularhodin from Sporobolomyces ruberrimus.

This work aimed at evaluating the influence of organic solvents and stationary phases in the extraction with glass beads and chromatographic purification of carotenoids, especially torularhodin, from Sporobolomyces ruberrimus. The combinations of acetone:hexane (1:1 v/v) and acetone:ethyl ether (1:1 v/v) yielded 171.74 and 172.19 μg of total carotenoids.g of cells-1, respectively. The first blend resulted in the highest percent of cell lysis of 57.4%. Among different proportions of acetone:hexane, the 9:1 v/v mixture showed a significant difference (p < 0.05), resulting in a recovery of total carotenoids of 221.88 μg.g of cells-1. The purification of carotenoids was made by preparative chromatography and the yield of the silica-containing stationary phase was higher (24 μg torularhodin.g cells-1). The analyses of the purified fractions in thin layer chromatography and high performance liquid chromatography indicated that the purification of carotenoids, especially of torularhodin, was successfully performed. The combination of polar (acetone) and non-polar solvents (hexane) and the use of silica as stationary phase was efficient to recover and purify torularhodin from the intracellular pigments of Sporobolomyces ruberrimus.

Facile Synthesis and Size Control of 2D Cyclodextrin‐Based Metal–Organic Frameworks Nanosheet for Topical Drug Delivery

AbstractIn this work, a 2D nanosheet (NS) of γ‐cyclodextrin (CD)‐based metal–organic frameworks (MOFs) is synthesized through a facile green chemistry approach. NS‐MOF carrier is constructed using a water system in a simple one‐pot reaction involving CD and potassium carbonate. Particle size optimization is achieved by adjusting the reaction temperature and the introduction of crystal growth suppressor (appropriate proportion of acetone). The NS‐MOF stability in aqueous medium is improved by polymerization reaction of crosslinked CD‐MOF (CL‐CD‐MOF) without blocking its cavity for drug loading. The effects of particle geometry and size of nanoporous materials on their pharmacokinetics during drug delivery are compared between the sheet‐like DXM@CL‐NS‐MOF and 3D‐cubic‐shaped DXM@CL‐CD‐MOF loaded with the same quantity of dexamethasone (DXM). The bioefficiency of these carriers in tear fluids and aqueous humors to deliver DXM is investigated in vivo. The results demonstrate that the 2D‐nanosheet particles significantly improve precorneal residence time and intraocular bioavailability over the commercial Maxidex (0.1% dexamethasone) and its 3D‐cubes counterpart of similar chemical composition. It suggests that the geometry of a carrier play a significant role in the biodistribution, and the carrier of CL‐NS‐MOF is a good candidate for ocular drug delivery.

Spheroidal crystal morphology of RDX in mixed solvent systems predicted by molecular dynamics

The crystal morphology of RDX largely affects its stability, dispersion, and energy output. The influence of the solvent on the crystal morphology plays a key role. A molecular dynamics method is used to calculate the interaction energies between five important crystal planes of RDX and the solvent layer under the action of cyclohexanone/water and dimethyl sulfoxide/acetone mixed solvents. The attachment energies are modified and the crystal morphologies of RDX under the effect of different volume ratios of the mixed solvents are predicted. The results show that the five important crystal planes of RDX are attracted to the two mixed solvents. Compared with the (111) and (210) faces, the (200), (002), and (020) faces show more obvious growth phenomena under the action of the two mixed solvents. When the mixed solvent is cyclohexanone/water, the lower the proportion of cyclohexanone, the closer the RDX crystal morphology is to spherical. When the mixed solvent is dimethyl sulfoxide/acetone, if spheroidal RDX is desired, the proportion of acetone should be greater than or equal to the proportion of dimethyl sulfoxide. The radial distribution functions between O atoms of the (111) face and H atoms in the two mixed solvents under different volume ratios are analyzed to explore the interaction forces at the interfaces.

Aqueous acetone fractionation of kraft, organosolv and soda lignins

Technical lignins are structurally heterogeneous and polydisperse. This work describes the use of a simple and green method for lignin fractionation, using different proportions of acetone (40 and 60%) in water. Lignins from three different sources (wheat straw organosolv lignin, wheat straw soda lignin and softwood kraft lignin) were used in this fractionation protocol. The obtained fractions showed different molar mass and functional groups. The lower molar mass fractions showed more phenolic hydroxyl groups and carboxylic acid moieties than higher molar mass fractions, which also possessed much higher amounts of carbohydrates. The chemical characterization of these fractionated lignins showed that the PREC fraction was exceptionally pure and homogeneous lignin. Its total lignin content was >96% for all three lignins and it was practically free from carbohydrates and inorganics (ash). Furthermore, PREC fraction possessed the highest carbon content for the three lignin samples (63.05–69.26%). These results illustrate that the proposed aqueous acetone fractionation protocol could indeed produce pure and uniform lignin fraction and it was applicable for lignins from different sources.

Fractionation of Organosolv Lignin Using Acetone:Water and Properties of the Obtained Fractions

Lignin fractions with different molecular weight were prepared using a simple and almost green method from switchgrass and pine organosolv lignin. Different proportions of acetone in water, ranging from 30 to 60%, were used for lignin fractionation. A higher concentration of acetone dissolved higher molecular weight fractions of the lignin. Fractionated organosolv lignin showed different molecular weight and functional groups. Higher molecular weight fractions exhibited more aliphatic and less phenolic OH than lower molecular weight fractions. Lower molecular weight fractions lead to more homogeneous structure compared to samples with a higher molecular weight. All fractions showed strong antioxidant activity.

Effect of operating conditions on the sorption enhanced steam reforming of blends of acetic acid and acetone as bio-oil model compounds

Hydrogen production by sorption enhanced steam reforming (SESR) of bio-oil model compounds was thermodynamically and experimentally studied by mixing acetic acid (AcH) and acetone (AcCO), in a fluidized bed reactor. In the SESR process the catalytic reforming reaction and CO2 removal by sorption were carried out simultaneously in a single reactor. The SESR of the model compounds and their blends was performed under atmospheric pressure over a Pd/Ni–Co hydrotalcite-like material (HT) catalyst using dolomite as CO2 sorbent. The effects of the reaction temperature (475–725°C), steam/C molar ratio and weight hourly space velocity (WHSV) were studied. For the SESR of acetic acid, acetone and their blends it was observed that the H2 yield and H2 concentration increase as the temperature increases, reaching a maximum value, and then they decrease with the temperature. It was also found that the CH4 concentration decreases as the temperature increases, while the CO and CO2 concentrations increase with the rise in temperature. High steam/C molar ratio values and low WHSV values favor the H2 yield and H2 concentration, while they lead to a decrease in the CH4 concentration. Hydrogen purities as high as 99.2–99.4% with small amounts of methane, CO and CO2 were obtained for the SESR of the model compounds of bio-oil and their blends at a temperature of 575°C at atmospheric pressure. The effect of temperature on the SESR of the blends of model compounds of bio-oil is similar to that of the individual model compounds studied, except in the fact that lower H2 yield values are obtained by the SESR of the blends (83.3–88.6%) compared to the individual model compounds (90.2–95.9%), a decrease which becomes more noticeable as the proportion of acetone in the blend is increased.

Chemical Constituents of Ficus linearifolia and Ficus triangularis

Ficus linearifolia Elmer is an endemic Philippine fig tree distributed in the forests of Luzon, Negros, and Leyte at altitudes up to 900 m above sea level [1]. It was earlier considered as a mere variety of Ficus botryocarpa Miq. [2]. This fig tree was first described in 1907 as an erect tree that reaches a height of 20 m and bears linear lanceolate leaves that are more or less scattered but usually confined towards ends of the branchlets. It grows in low damp wooded ground or along streams in deep ravines at the base of Mt. Banahao (Lucban, Luzon Island) at 750 m above sea level [3]. This fig tree is locally known in the Philippines as daing-daing [4]. Ficus triangularis, commonly known as triangular fig and sweetheart tree, is a native to tropical Africa. It was recently introduced in the Philippines as an ornamental tree [5]. This study was conducted as part of our research on the chemical constituents of the genus Ficus. We earlier reported the isolation of a new neohopane [6] from Ficus pumila. We also reported the isolation of terpenoids and sterols from the endemic Philippine trees, Ficus pseudopalma and Ficus ulmifolia [7]. Recently, we reported the isolation of terpenoids and sterols from another endemic Philippine tree, Ficus odorata. -Sitosteryl-3 -glucopyranoside-6-O-palmitate from the leaves of F. odorata exhibited cytotoxicity against human stomach adenocarcinoma cell line (AGS) with 60.28% growth inhibition [8]. There are no reported chemical constituents and biological activities of F. linearifolia and F. triangularis. We report herein the isolation and structure elucidation of 1–9 from the dichloromethane extract of the air-dried leaves of Ficus linearifolia and 4–13 from the leaves of F. triangularis. To the best of our knowledge, this is the first report on the isolation of these compounds from these trees. Silica gel chromatography of the dichloromethane extract of the leaves of F. linearifolia afforded 1–9. The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by comparison of their 13C NMR data with those of 11 ,12 -epoxyurs-14-en-3 -yl acetate [9]. The structures of 2–9 were identified by comparison of their 13C NMR data with those reported in the literature for -amyrin (2) [10], -amyrin (3) [10], squalene (4) [11], -sitosterol (5) [12], -stigmasterol (6) [12], polyprenol (7) [13], linoleic acid (8) [14], lutein (9) [15]. The leaves of Ficus linearifolia were collected from the foot of Mt. Banahaw, at around 600 m above sea level (masl), at Avila s Farm, Brgy Palola, Lucban, Quezon, Philippines in March 2012. Voucher specimens were authenticated by Danilo N. Tandang of Philippine National Museum. The air-dried leaves (310 g) of F. linearifolia were soaked in CH2Cl2 for 3 days and then filtered. The filtrate was concentrated under vacuum to afford the crude extract (6 g), which was chromatographed in increasing proportions of acetone in CH2Cl2 at 10% increments by volume as eluents. The CH2Cl2 fraction was rechromatographed (4 ) in petroleum ether to afford 4 (8 mg). The 10% acetone in CH2Cl2 fraction from the chromatography of the crude extract was rechromatographed (3 ) in 7.5% EtOAc in petroleum ether to afford 1 (12 mg). The 20% acetone in CH2Cl2 fraction from the chromatography of the crude extract was rechromatographed (4 ) in 10% EtOAc in petroleum ether to afford 7 (10 mg). The 30% acetone in CH2Cl2 fraction was rechromatographed (3 ) in 15% EtOAc in petroleum ether to afford 8 (15 mg) and a mixture of 2 and 3 (9 mg).

Chemical Constituents of Cinnamomum iners

Cinnamomum iners, a species closely similar to C. subcuneatum Miq., is an evergreen medium height tree with reddish brown and smooth branchlets. Cinnamomum iners is widely distributed in Southeast Asia from Indochina, Sumatra, Pensular Malaysia, Java, and the Philippines [1]. Previous studies reported the presence of -caryophyllene, stigmasterol, cardiac glycoside, flavonoid, polyphenol, saponin, sugar, tannin and terpenoid in the tree [2]. This study was conducted as part of our research on the chemical constituents of Cinnamomum species found in the Philippines. We earlier reported the isolation of a new monoterpene natural product and a new sesquiterpene, along with the known compounds 4-hydroxy-3-methoxycinnamaldehyde, 4-allyl-2-methoxyphenol, -terpineol, and humulene from the bark of C. cebuense, while the leaves afforded humulene, -caryophyllene, squalene, and a mixture of -amyrin, -amyrin, and bauerenol [3]. We also reported the presence of 1 ,4 ,7 -trihydroxyeudesmane, 4 -hydroxy-5,7,3 -trimethoxyflavan-3-ol, squalene, polyprenol, and a mixture of -amyrin, -amyrin, and bauerenol from the dichloromethane (DCM) extract of the bark of C. griffithii, and squalene and benzyl benzoate from the leaves [4]. Silica gel chromatography of the DCM extract of the bark of C. iners from Guimaras Island, Philippines afforded 5,7-dimethoxy-3 ,4 -methylenedioxyflavan-3-ol (1) and -sitosterol (2), which were also obtained from the DCM extract of the twigs of C. iners together with 4-(4-hydroxy-3-methoxyphenyl)but-3-en-2-one (3), cinnamaldehyde (4), linoleic acid (5), and vanillin (6). The leaves of C. iners afforded eugenol (7), linoleic acid (5), and -sitosterol (2). The structures of 1, 3, and 4 were elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by comparison of their 13C NMR data with those reported in the literature for 5,7-dimethoxy-3 ,4 -methylenedioxyflavan-3-ol [5], 4-(4-hydroxy-3-methoxyphenyl)but-3-en-2-one [6], and cinnamaldehyde [7], respectively. The structures of -sitosterol (2) [8], linoleic acid (5) [9], vanillin (6) [10], and eugenol (7) [11] were confirmed by comparison of their 13C NMR data with those reported in the literature. The bark and leaves of Cinnamomum iners were collected from Guimaras, Philippines in May 2011. Voucher specimens were authenticated by one of the authors (EMGA) and deposited in the De La Salle University-Manila Herbarium (DLSU3103). The bark of C. iners was chopped into small pieces and then air dried. The air-dried bark (313.3 g) was soaked in DCM for 3 days and then filtered. The filtrate was concentrated under vacuum to afford the crude extract (7.1 g), which was chromatographed in increasing proportions of acetone in DCM at 10% increments as eluents. The 10% acetone in DCM fraction from the chromatography of the crude extract was rechromatographed (3 ) in 1% ethyl acetate in petroleum ether, then (2 ) in 2.5% ethyl acetate in petroleum ether to afford 2 (25.0 mg). The 20% acetone in DCM fraction was rechromatographed (5 ) in 5% ethyl acetate in petroleum ether, then (3 ) in 7.5% ethyl acetate in petroleum ether as eluents to afford 1 (12.0 mg). The air-dried twigs of C. iners (112.9 g) were ground in an osterizer, soaked in DCM for 3 days, and then filtered. The filtrate was concentrated under vacuum to afford the crude extract (1.6 g), which was chromatographed in increasing proportions of acetone in DCM at 10% increments as eluents. The DCM fraction from the chromatography of the crude extract was rechromatographed (6 ) in petroleum ether to afford 4 (10.0 mg). The 20% acetone in DCM fraction was rechromatographed (3 ) in 15% ethyl acetate in petroleum ether, then (3 ) in DCM as eluents. The less polar fractions yielded 2 (15.0 mg), while the more polar eluents afforded 3 (12.0 mg). The 30% acetone in DCM and 40% acetone in DCM

Chemical Constituents of Cinnamomum rupestre and Cinnamomum nanophyllum

Cinnamomum rupestre Kosterm. (Lauraceae) is an endemic species in the Philippines originally discovered in Palawan [1], while Cinnamomum nanophyllum Kosterm. is a widespread endemic species in the country. In Cebu, the local people collect and prepare the leaves and the bark as a decoction for relief of stomach and abdominal ailments. There are no reported chemical and biological studies on C. rupestre and C. nanophyllum. These are two of the 21 species of Cinnamomum found in the Philippines, of which 16 are known to be endemic [1]. This study was conducted as part of our research on the chemical constituents of Cinnamomum species found in the Philippines. We earlier reported the isolation of eugenol and safrole from the bark, polyprenol from the leaves, and trilinolein from the roots of Cinnamomum cebuense [2]. Silica gel chromatography of the dichloromethane (DCM) extract of the bark of C. rupestre afforded 4 -hydroxy5,7,3 -trimethoxyflavan-3-ol (1), 4-hydroxy-3-methoxycinnamaldehyde (2), and 4-allyl-2-methoxyphenol or eugenol (3), while the leaves yielded -sitosterol (4). The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by comparison of its 13C NMR data with those reported in the literature for 4 -hydroxy-5,7,3 -trimethoxyflavan-3-ol (1) [3]. The structures of 4-hydroxy-3-methoxycinnamaldehyde (2) [4], 4-allyl-2-methoxyphenol or eugenol (3) [5], and -sitosterol (4) [6] were confirmed by comparison of their 13C NMR data with those reported in the literature. The DCM extract of the bark of C. nanophyllum afforded 1, 2, 4, and trilinolein (5), while the leaves yielded 4. The structure of trilinolein (5) [7] was confirmed by comparison of its 13C NMR data with those reported in the literature. To the best of our knowledge, this is the first report on the chemical constituents of C. rupestre and C. nanophyllum. The bark and leaves of Cinnamomum rupestre and Cinnamomum nanophyllum were collected from Hagnaya, Carmen, Cebu, Philippines in June 2010. Voucher specimens of Cinnamomum rupestre and Cinnamomum nanophyllum were authenticated by one of the authors (EMGA) and deposited in the De La Salle University-Manila Herbarium (DLSU-3101 and DLSU-3102, respectively). The air-dried bark and leaves of C. rupestre were chopped into small pieces and then air dried. The air-dried bark (371.8 g) and leaves (89.1 g) were soaked in DCM for 3 days and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts of bark (16.6 g) and leaves (7.0 g), which were fractionated by silica gel chromatography using increasing proportions of acetone in DCM (10% increment by volume) as eluents. The DCM fraction from the bark was rechromatographed in petroleum ether (7 ) to afford 3 (28 mg). The 30% acetone in DCM fraction was rechromatographed with 12.5% ethyl acetate in petroleum ether as eluent to afford 2 (18 mg). The 40% acetone in DCM fraction was rechromatographed (5 ) in DCM, then (8 ) in diethyl ether–acetonitrile–DCM (0.5:0.5:9) to afford 1 (12 mg). The DCM fraction from the leaves was rechromatographed (3 ) in 5% ethyl acetate in petroleum ether to afford 4 (10 mg). The air-dried bark and leaves of C. nanophyllum were chopped into small pieces and then air dried. The air-dried bark (493.5 g) and leaves (49.5 g) were soaked in DCM for three days and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts of bark (8.0 g) and leaves (9.5 g), which were fractionated by silica gel chromatography using increasing proportions of acetone in DCM (10% increment by volume) as eluents. The crude DCM extract of the bark of C. nanophyllum was chromatographed in increasing proportions of acetone in DCM at 10% increment as eluents. The 10%

Terpenoids from Ardisia squamulosa

The genus Ardisia Swartz belongs to the family Myrsinaceae. Ardisia has 68 recorded species in the Philippines [1], 60 of which are endemic. The hexane extract from A. squamulosa was reported to have a significant effect on sperm count but has a negligible effect on sperm morphology and viability [2]. No chemical study of A. squamulosa has been reported. However, we earlier studied a congener of this plant, Ardisia pyramidalis, which afforded spinasterol, spinasteryl acetate, a mixture of -amyrin, -amyrin and bauerenol, squalene, lutein, and triglycerides from the dichloromethane (DCM) extract of the leaves. Spinasterol was found to exhibit anti-angiogenic potential [3]. This study was conducted as part of our research on the chemical constituents of Ardisia species found in the Philippines. We report herein the chemical constituents of the DCM extract of the leaves of A. squamulosa. Fresh leaves of Ardisia squamulosa were collected from Kanawan, Morong Bataan, Philippines in 2010 by Ramon Bandong. The sample was authenticated by the Jose Vera Herbarium Collection at the Institute of Biology of the University of the Philippines-Diliman and the Philippine National Museum, Manila. The DCM extracts of the air-dried leaves of A. squamulosa afforded terpenoids by silica gel chromatography. These compounds were identified by comparison of their 13C NMR data with those of -caryophyllene (1) [4], squalene (2) [5], bauerenone (3a) [6], ursenone (3b) [7], oleanone (3c) [7], bauerenol (4a) [6], -amyrin (4b) [8], -amyrin (4c) [8], and lutein (5) [9] reported in the literature. Air-dried leaves of Ardisia squamulosa (1 kg) were ground in an Osterizer and then soaked in DCM for three days and filtered. The filtrate was concentrated in vacuo to afford a crude extract (55 g), which was chromatographed in increasing proportions of acetone in dichloromethane at 10% increment. The DCM fraction was rechromatographed (6 ) in petroleum ether to afford 1 (5 mg) and 2 (20 mg). The 10% acetone in DCM and 20% acetone in DCM fractions were combined and rechromatographed (4 ) with 2.5% ethyl acetate in petroleum ether as eluent to afford a mixture of 3a–3c (12 mg). The 30% acetone in DCM fraction was rechromatographed (5 ) using 5% ethyl acetate in petroleum ether to afford a mixture of 4a–4c (15 mg). The 40% acetone in DCM and 50% acetone in DCM fractions were combined and rechromatographed (3 ) with DCM–diethyl ether–acetonitrile (9:0.5:0.5) as eluent to afford 5 (18 mg) after washing with diethyl ether.

Accuracy of SOBO 20 in the Measurement of Salt on Winter Pavements

The use of chemicals is essential in snow and ice control operations. Sodium chloride (salt) is normally used, because it is efficient, widely available, and relatively inexpensive. However, it is harmful for the environment if large quantities are used, and currently there is much attention placed on the importance of reducing the usage of salt while road serviceability and safety are maintained. Optimizing the use of salt requires accurately knowing how much salt is already on a pavement surface. Unfortunately, there is currently no well-documented method available to determine this quantity. SOBO 20 is one of the most common instruments used by the winter maintenance community to calculate salt amounts, although the reliability of the instrument has not yet been shown. The present work aims to fill this gap by carrying out measurements on brine (dissolved salt), dry salt particles, and recrystallized salt. The presented results support the conclusion that SOBO 20 is an accurate and reliable instrument for measuring brine on asphalt pavements. However, the instrument largely underestimates the amount of dry or recrystallized salt, and more attention should be paid when SOBO 20 is used on dry pavements. Compliance with the manufacturer's recommendations regarding the proportion of acetone in the measuring fluid is also essential for accurate salt readings. These results on the instrument performance should lead to a better understanding of salt distribution and action time.

Effect of solvent composition during preparations on the characteristics of enoxacin microparticles.

We have studied the effect of the solvent system during preparation on the morphology, encapsulation efficiency, and release characteristics of enoxacin microparticles intended for localized delivery to the bone for the treatment of bone infections. Microparticles of enoxacin were formulated using poly(glycolic acid-co-DL-lactic acid) (PGLA) of different viscosity grades by the solvent-evaporation technique. Microparticles prepared with pure dichloromethane had smoother surfaces and less tendency to aggregate than microparticles prepared with dichloromethane-acetone solvent mixtures, which had porous surfaces. Approximately 65% of the microparticles prepared with pure dichloromethane were < 125 microm in diameter compared with 16% (approx.) of microparticles prepared with dichloromethane-acetone mixtures. Increasing the proportion of acetone from dichloromethane-acetone, 10:0, to dichloromethane-acetone, 1:1, resulted in an increase in encapsulation efficiency from 25 to 37%, and an increase in the yield of microparticles harvested from 39 to 51%. Although a further increase in the amount of acetone to dichloromethane-acetone, 1:9, had no significant effect on the yield, aggregation, or fraction of microparticles below 125 microm in diameter, the encapsulation efficiency increased to 56%. Approximately 55% of enoxacin was released in 24 h for microparticles prepared with dichloromethane-acetone, 1:9, compared with 100% release in 10h and 2h for microparticles of the same size range prepared with dichloromethane-acetone, 1:1, and dichloromethane-acetone, 10:0, respectively. The results suggest that the composition of the dichloromethane-acetone solvent system significantly influences the encapsulation efficiency and the rate of release of enoxacin from microparticles. This is important for the formulation of sustained-release enoxacin microparticles for the localized treatment of osteomyelitis.

Dependence of Performance of Poly(Sulfone‐co‐Amide) Membranes on Compositional Variation of Casting Solution and Coagulation Media—Development of Reverse Osmosis and Nano Filtration Membranes

Poly(sulfone‐co‐amide) polymer was synthesized by a low temperature solution polycondensation technique from benzene 1,3 dicarboxylic acid chloride (isophthaloyl chloride), benzene 1,4 dicarboxylic acid chloride [terephthaloyl chloride (TPC)], and bis[4‐amino phenyl] sulfone, i.e., (4,4′‐diamino diphenyl sulfone) as monomers using N,N dimethyl acetamide (DMAc) as solvent cum acid acceptor. Casting solutions using various combinations of DMAc and acetone as solvent and LiCl and LiNO3 as additives were prepared. Wet phase inversion membranes were prepared from them at ambient temperature (25°C) using demineralized water (DMW) or aqueous sodium dodecyl sulfate (SDS) as coagulation media. Solute rejections of the membranes increased and solvent flux decreased with increasing proportion of acetone and decreasing DMAc content in the casting solution. Use of 1% and 2% aqueous SDS solution as gelling media improved the flux of the membranes significantly. Evaporation of solvent at room temperature prior to gelling, in certain cases, led to high solute rejecting membranes. By the proper combination of casting solution composition, evaporation time, and gelling medium, it was possible to make a range of NF membranes and also high solute rejecting brackish water RO membranes from the single polymer. More importantly, use of a significant amount of acetone in the casting solution enabled us to make high solute rejecting integrally skinned asymmetric membranes simply by evaporation of solvent followed by coagulation in a proper medium, all at ambient temperature. The membranes do not need any other treatment before use.

Optimization of HSA and NGF encapsulation yields in PLGA microparticles

The aim of this study was to prepare, in a reproducible manner, poly( d, l-lactide-co-glycolide) (PLGA) biodegradable microparticles with high encapsulation yield of nerve growth factor (NGF), a neurotrophic factor of interest in the treatment of neurodegenerative diseases. Human serum albumin (HSA) was co-encapsulated with NGF by the w/o/w emulsion solvent evaporation/extraction method to stabilize the primary emulsion and to protect NGF. The encapsulation yield optimization was first carried out with HSA alone since it was the major component in the final microspheres, as compared to NGF. The effects of ten process factors on HSA entrapment in PLGA microspheres were examined using a fractional factorial design. Four major factors were identified. The presence of carboxymethylcellulose sodium or mannitol in the internal aqueous phase, the increase of the internal aqueous volume and the concentration of HSA led to a decrease of the encapsulation yield. Two main factors, namely the internal aqueous phase volume and the proportion of acetone in the organic phase, previously identified as a predominant factor, were studied through a response surface methodology. The observed range of HSA encapsulation yield was 87.4–100%. NGF was encapsulated according to the optimal conditions found for the entrapment of HSA. The encapsulation yield was then 97.3±5.0%.

MEASUREMENT OF RADIATION INDUCED LOCALIZED ABSORPTION IN CHROMATOGRAPHIC ELUENTS BY MEANS OF THE CO LASER AND THE PZT PYROELECTRIC DETECTOR

Combined use of the CO laser and PZT piezoelectric detector is proposed as a sensitive and specific detector for gas chromatography. The feasibility of this detection scheme is demonstrated for a model mixture containing varying proportions of acetone in water. After separation on a GC column, spectra of both constituents were recorded in the 1600 cm−1 to 1900 cm−1 range that encompasses the characteristic frequency of C=O bond in acetone. Reasonably high sensitivity (mass concentration limit is 1.2x10−8 g acetone) and a good degree (factor 530) of spectral discrimination was achieved by a proper selection of analytical wavelengths.

Evaluation of the ability of different concentrations of aqueous acetone, aqueous methanol and aqueous acetone: Methanol (1∶1) to extract aflatoxin from naturally contaminated maize

A conventional TLC tank was compared with a specially designed continuous linear development chamber for the ether development phase of the quantitation of aflatoxins by bi-directional High Performance Thin Layer Chromatography (HPTLC). No significant difference was detected in the precision of the method. However, the continuous linear development chamber afforded greater accuracy in aflatoxin determination and required only half the development time and a small fraction of the solvent used in the conventional TLC tank. The ability of different concentrations of aqueous acetone, aqueous methanol and aqueous acetone: methanol (1∶1) to extract aflatoxin from naturally contaminated maize was assessed. With each system, the amount of aflatoxin extracted increased as the ratio of organic solvent: water progressed from 50∶50 to 80∶20 and then decreased or remained constant when the composition of the extraction solvent was altered to 90∶10. 80% aqueous acetone was found to extract 27% more aflatoxin than the corresponding aqueous methanol with the mixed solvent system extracting an intermediate amount of toxin. Clean-up of 80% aqueous acetone extracts of maize by elution through phenol (PH) bonded-phase cartridges resulted in poor aflatoxin retention when the proportion of acetone in 5 ml aliquots of extract was greater than 70%. This could be increased to 100% retention by the addition of an equal quantity of methanol prior to dilution with 1% aqueous acetic acid and elution through the cartridge.