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At least 235 records · Page 13Linked to original sources

PubMed2005

Fluorescence rejection in Raman spectra of Syncrude Sweet Blend distillation fractions.

Four techniques for the reduction or elimination of fluorescence from Raman spectra of Syncrude process samples were examined in this study. These methods are based on the retrieval of Raman bands from differential, or derivative spectra. Differential data were generated by subtracting similar spectra of a given sample obtained in three ways: (a) shifted detection utilizing an array detector and two successive spectrometer settings; (b) shifted excitation (dispersive Raman) where the two spectra are recorded using neighbouring laser lines and ordinary photon counting; (c) shifted excitation (FT-Raman) in which the laser frequency is changed in software before acquisition of the second spectrum. In addition to these differential techniques, derivative spectra were acquired directly with a dispersive Raman system by modulating the wavelength during scanning. These fluorescence rejection methods were applied to two groups of Syncrude Sweet Blend distillation fractions. For light gas oils (boiling range, 195-343 degrees C) the ratio of monocyclic and bicyclic aromatic species was determined and bands due to aliphatic CH(n) groups were characterized. Heavy gas oils (343-524 degrees C) yielded bands that allowed quantitation of monocyclic, bicyclic and total aromatic groups. Bands due to aliphatics were also identified for the heavy gas oils. These results constitute a significant advance compared to the information obtainable using conventional dispersive and FT-Raman spectroscopy for the analysis of hydrocarbon distillation fractions.

Hydrocarbons↗

PubMed2003

Short-term fluoride and cations release from polyacid-modified composites in a distilled water, and an acidic lactate buffer.

Fluoride and various cations release from three commercial compomers (Dyract, Dyract AP and Compoglass-F) and a resin-modified glass ionomer (Fuji-II LC) as a control were measured up to 7 days in distilled water and 0.01M lactate buffer solution with pH 4.1. The surface morphological change before and after the release experiment was observed with a scanning electron microscopy. Fluoride, aluminum and strontium ions were released from Dyract, Dyract AP and Fuji-II LC much more in the lactate buffer than in the distilled water. With compoglass-F containing barium instead of strontium, barium was released in the same way. X-ray diffraction analysis confirmed that fluoride release from Dyract and Dyract AP was derived mainly from SrF(2) contained in Dyract and Dyract AP. However, fluoride release from Compoglass-F was derived from glassy phase though it contained much fluoride as YbF(3). Cumulative release amount of each species versus square root of time plot showed good linearity, indicating that the dissolution was controlled by the diffusion mechanism. The surface characteristics of disks for each material, which were immersed in the lactate buffer, were quite different from the surface before and after immersion in deionized water, especially with Dyract. After immersion in the lactate buffer, many voids which were left after dissolution of the filler particle, were seen obviously on the surface of Dyract.

Aluminum↗

PubMed1999

Derepression of galactose metabolism in melibiase producing bakers' and distillers' yeast.

Beet molasses is widely used as a growth substrate for bakers' and distillers' yeast in the production of biomass and ethanol. Most commercial yeasts do not fully utilise the carbohydrates in molasses since they are incapable of hydrolysing the disaccharide melibiose to glucose and galactose. Also, expression of genes encoding enzymes for the utilisation of carbon sources that are alternatives to glucose is tightly regulated, sometimes rates of yeast growth and/or ethanol production. The GAL genes are regulated by specific induction by galactose and repression during growth on glucose. In an industrial distillers' yeast, two genes interacting synergistically in glucose repression of galactose utilization, MIG1 and GAL80, have been disrupted with MEL1, encoding melibiase. The physiology of the wild-type strain and the recombinant strains was investigated on mixtures of glucose and galactose and on molasses. The recombinant strain started to ferment galactose when 9.7 g 1(-1) glucose was still present during a batch fermentation, whereas the wild-type strain did not consume any galactose in the presence of glucose. The ethanol yield in the recombinant strain was 0.50 g ethanol g sugar (-1) in an ethanol fermentation on molasses, compared with 0.48 g ethanol g sugar (-1) for the wild-type strain. The increased ethanol yield was due to utilization of melibiose in the molasses.

Culture Media↗

PubMed1982

Effects of endotracheally administered distilled water and normal saline on the arterial blood gases of dogs.

The effects of endotracheally (ET) administered distilled water (DW) and normal saline solution (NSS) on the arterial blood gases of dogs were compared. When distilled water was administered endotracheally, arterial pH was depressed to 99.36% of baseline values within 5 minutes. When compared to pH changes following ET administration of NSS the depression of pH following DW administration was significant (P less than .05). Following ET injection of DW, arterial PO2 was depressed to 61% of baseline values and remained significantly depressed throughout the experiment. In comparison, following ET NSS administration, PO2 was depressed substantially less, and remained at significantly higher levels for the entire experiment. In dogs, administration of NSS by the ET route produces less detrimental effects on arterial blood gases than does the ET administration of DW. This may have implications for the choice of diluent for human drug administration using the ET route.

Analysis of Variance↗

PubMed2001

Dry-distillation of astatine-211 from irradiated bismuth targets: a time-saving procedure with high recovery yields.

Astatine-211 was produced via the 209Bi(alpha,2n) 211At reaction. The radionuclide was isolated with a novel procedure employing dry-distillation of the irradiated target material. The astatine was condensed as a dry residue in a PEEK-capillary cryotrap. Distillation was completed within 1-2 min with isolation yields of 92 +/- 3%. Subsequent work-up of the nuclide resulted in final recovery yields of 79 +/- 3%.

Astatine↗

PubMed2001

Fourier transform Raman spectroscopy of Syncrude sweet blend distillation fractions derived from Athabasca bitumen.

The C-H stretching region in FT-Raman spectra of Syncrude sweet blend (SSB) and three distillation fractions (naphtha, light gas oil and heavy gas oil) was analyzed in detail in this investigation. The frequencies and intensities of the 11 aliphatic and three aromatic C-H bands used to fit the spectrum of SSB were equal to the averages (weighted sums) of the corresponding quantities in the spectra of the fractions. The additivity of the spectra, thought to be a consequence of the large number of discrete compounds contained in each fraction, makes it possible to estimate the composition of other SSB samples using the spectra of the fractions reported in this work. In the aromatic C-H region, total intensities can be used to calculate the distribution of aromatics among the distillation fractions; these data also permit calculation of the fractional aromaticity (per cent aromatic carbon) for SSB and each fraction, with accuracies comparable to those obtained using NMR spectroscopy.

Alkanes↗

PubMed2003

Fourier transform Raman spectroscopy of Syncrude Sweet Blend distillation fractions: the 200-1800 cm-1 region.

The fingerprint (200-1800 cm(-1)) region in FT-Raman spectra of Syncrude Sweet Blend (SSB) and its three constituent distillation fractions (naphtha, light gas oil and heavy gas oil) was analyzed in detail in this study. Approximately 50 bands were observed and assigned to functional groups in saturated (alkanes) and unsaturated (aromatics) species. Characteristic bands for mono-, bi-, and tricyclic aromatics were identified and used to quantify these groups in SSB and the distillation fractions. Total aromatics content was determined using the carbon-carbon stretching bands in the 1600-cm(-1) region, and shown to agree with earlier results obtained from the C-H stretching region. The bands due to mono- and bicyclic aromatics permitted calculation of the relative abundances of these species with an accuracy equivalent to that obtained using NMR spectroscopy, a traditional method for measuring this quantity.

Alkanes↗

PubMed2006

Hemolysis in transurethral resection of the prostate using distilled water as the irrigant.

BACKGROUND: To investigate the incidence and time course of hemolysis and its clinical effects following transurethral resection of the prostate (TURP) using distilled water as the irrigant. METHODS: Between March 1996 and April 1997, 39 patients who underwent TURP due to benign prostatic hyperplasia (BPH) were randomly included in this study. The levels of plasma hemoglobin, haptoglobin and serum lactic dehydrogenase (LDH) were checked in all patients before, immediately after, and 24 hours after the operation. Serum creatinine and sodium were also checked in 24 patients starting August 1996. Significant hemolysis was identified as simultaneous elevation of plasma hemoglobin (> 10 g/dL), serum LDH and reduction of plasma haptoglobin after TURP. RESULTS: Among the 39 subjects, hemolysis occurred in 17 (43.6%), whose plasma hemoglobin and serum LDH increased while plasma haptoglobin decreased immediately after operation (p < 0.05), but no significant differences between the data before and 24 hours after the operation were noticed. In the hemolysis group, serum creatinine increased while serum sodium decreased immediately after operation (p < 0.05), but the data before and 24 hours after the operation had no significant differences. There were no changes in serum creatinine and sodium levels after TURP in patients without hemolysis. The weight of the resected prostate was 42.5 +/- 15.5 g in the hemolysis group and 23.3 +/- 8.3 g in the nonhemolysis group, while duration of TURP was 68.9 +/- 19.6 minutes in the hemolysis group and 34.2 +/- 8.4 minutes in the nonhemolysis group. Patients with hemolysis had higher resection weight and longer resection time than those without hemolysis (p < 0.001). CONCLUSION: Using distilled water as an irrigant for TURP might cause hemolysis, especially in patients with larger prostates and longer resection times. It is necessary to carry out every effort to shorten resection time and avoid extravasation during surgery.

Aged↗

PubMed2005

Laser-induced acoustic desorption/fourier transform ion cyclotron resonance mass spectrometry for petroleum distillate analysis.

Laser-induced acoustic desorption (LIAD) coupled with a 3-T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR) allows the simultaneous analysis of both the nonpolar and polar components in petroleum distillates. The LIAD/FT-ICR method was validated by examining model compounds representative of the various classes of polar and nonpolar hydrocarbons commonly found in petroleum. LIAD successfully desorbs all the compounds as intact neutral molecules into the FT-ICR. Electron ionization (EI) at low energies (10 eV) and chemical ionization using cyclopentadienyl cobalt radical cation (CpCo*+) were employed to ionize the desorbed molecules. The EI experiments lead to extensive fragmentation of many of the hydrocarbon compounds studied. However, the CpCo*+ ion ionizes all the hydrocarbon compounds by producing only pseudomolecular ions without other fragmentation, with the exception of one compound (*CH3 loss occurs). Examination of two different petroleum distillate samples revealed hundreds of compounds. The most abundant components have an even molecular weight; i.e., they are likely to contain no (or possibly an even number of) nitrogen atoms.

Journal Article↗

PubMed2002

Potentiometric flow injection determination of glycerol in distilled spirits.

A single-line flow injection system including a tubular periodate-selective electrode without inner reference solution is proposed for glycerol determination in distilled spirits, based on oxidation of this polyol by periodate. Interferences due to 5.0 mg L(-1) Cu, 5000 mg L(-1) sucrose, and 3000 mg L(-1) fructose plus glucose were investigated. The procedure is characterized by a linear response for 20-500 mg L(-1) glycerol (r > 0.9999, n = 7), a relative standard deviation of results of <0.03, and an analytical throughput of 30 determinations per hour. Accuracy was assessed by applying the procedure to distilled spirits of sugarcane and grape already analyzed by HPLC; in addition, recoveries within 96 and 120% were obtained.

Alcoholic Beverages↗

PubMed2003

Chemical and sensorial aroma characterization of freshly distilled Calvados. 1. Evaluation of quality and defects on the basis of key odorants by olfactometry and sensory analysis.

Eight freshly distilled samples of Calvados, a fermented and distilled apple juice, were analyzed by sensory evaluation and direct injection GC to determine the composition of higher alcohols, esters, and aldehydes. The composition determined by direct injection was tentatively related to sensory descriptors. Esters have a probable maximum level around 500 g/hl of pure alcohol (PA). This level also corresponds to the threshold of the main ester constituent, ethyl acetate. A high ratio of esters to ethyl acetate seems to be of prime importance for good quality. Total aldehydes, with a maximum level between 8 and 11 g/hl of PA and mainly comprising acetal (maximum between 5 and 9 g/hl of PA), were related to a "green" descriptor. Higher alcohols do not have a direct impact on quality, but other volatile compounds with a positive impact on flavor should probably be present at a high level. As overall quality was not well related to sensory quality, it was necessary to perform more a precise analysis to determine the key odorants. The Calvados samples were thus extracted using pentane. Gas chromatography, employing both a flame ionization detector and an olfactometry port, was used to analyze the obtained extracts. Seventy-one odors were detected and distributed according to Calvados quality determined by sensory evaluation. Nineteen odors common to all Calvados samples constituted the "skeleton" of the aroma. Twenty-eight odors were specific to a quality class: 6 for good quality, 4 for neutral, and 18 for defective. Twenty-four other odors had either too low an odor impact or no evident specificity.

Acetates↗

PubMed2003

Extraction of essential oil and pigments from Curcuma longa [L] by steam distillation and extraction with volatile solvents.

Curcuma longa [Linn] (turmeric), of the Zingiberaceae family, has a great importance in the food, textile, and pharmaceutical industries. The aim of this work was to identify the best processing conditions to maximize the yields of essential oil and pigments, as well as their content of ar-turmerone, (alpha and beta)-turmerone, and the curcuminoids, respectively. Autoclave pressure and distillation time were the variables studied for the steam distillation process. The highest yields of essential oil (0.46 wt %) and pigment (0.16 wt %)-expressed as curcumin, demethoxycurcumin, and bisdemethoxycurcumin-were obtained at a pressure of 1.0 x 10(5) Pa and a time of 2 h. On the other hand, with extraction by volatile solvents, the best yield of essential oil (5.49 wt %) was obtained when using 0.175, 0.124, 0.088 mm particles (Foust, A. S.; Wenzel, L. A.; Clump, C. W.; Maus, L.; Andersen, L. B. Princípios das Operações Unitárias; Editora Guanabara Dois S.A.: Rio de Janeiro, Brazil, 1982), at 40 degrees C, and 6 h of extraction. However, the best yield of pigment (7.98 wt %) was obtained under the same conditions, except for the temperature (30 degrees C).

Curcuma↗

PubMed2004

Determination of key odorant compounds in freshly distilled cognac using GC-O, GC-MS, and sensory evaluation.

This aim of this work was to identify the odorant compounds responsible for the typical sensory descriptors attributed to freshly distilled Cognac spirits, not matured in barrels. Panelists were first selected and trained for gas chromatography-olfactometry. Among the 150 volatile compounds identified by gas chromatography-mass spectrometry analysis, only 34 are mainly responsible for the odors detected in the spirits. The "butter" descriptor is explained by the presence of diacetyl, the "hay" descriptor by nerolidol, the "grass" descriptor mainly by Z-3-hexen-1-ol, but also by other compounds, the "pear" and "banana" descriptors by 2- and 3-methylbutyl acetates, the "rose" descriptor by 2-phenylethyl acetate, and the "lime tree" descriptor by linalool. This study demonstrated that many odorant molecules are already present in freshly distilled Cognac, thereby giving the spirit its specific aroma.

Alcoholic Beverages↗

PubMed2004

Combination of supercritical CO2 and vacuum distillation for the fractionation of bergamot oil.

Supercritical CO2 can be used to separate oxygenated compounds from essential oils. This technique still cannot replace vacuum distillation as an industrial process because of low recoveries and inconsistent results. In the present work, a comparison between the two methods was made in terms of composition, recovery, and color. Vacuum distillation and supercritical CO2 are complementary processes for producing high quality oxygenated compounds with high recovery rates. The former is more suitable for removing monoterpenes at low fraction temperatures (< or =308 K), and the latter is more suitable for separating oxygenated compounds from pigments and waxes. Consequently, the two methods were combined. For supercritical CO2 fractionation, the parameters of pressure, temperature gradient, and the ratio of solvent to feed were investigated for the fractionation of oxygenated compounds with high recoveries (> or =85%) and without other macromolecules, such as pigments and waxes.

Chemical Fractionation↗

PubMed2006

Glass distilling collector applied for HCN recovery from submerged culture broth and fruiting body of Pleurotus eryngii for identification and quantification.

Detection and surveillance of food commodities containing cyanide is a crucial issue of food safety. In this study, five strains of Pleurotus eryngii (P. eryngii) were grown in submerged culture of yeast malt broth (YMB) with the suspected production of HCN. A safety-warranted U-bent glass distilling collector with three enlarged bulbs on each arm was designed to recover the broth vapor. When AgNO(3) solution was used as an absorbent to interact with the vapor, a white precipitate was formed. The precipitate was isolated and identified as AgCN by FT-Raman spectroscopic analysis. When the absorbent was substituted by KOH, after evaporation to dryness, dissolved in D(2)O, and followed by (13)C-NMR analysis, a KCN spectrum was achieved. Formation of AgCN and KCN confirmed HCN production in the broth by P. eryngii. When a sodium picrate solution (1.4%) was used as an absorbent and various authentic KCN solutions were applied for distillation and followed by absorbance determination at 510 nm, a linear dose-dependent relationship was obtained and the procedure was applied for HCN quantification of the marketed P. eryngii mushrooms (fruiting body). As estimated, 67.3% of the products contained HCN less than 1.0 mg/kg, 17.3% between 1.0 and 2.0 mg/kg, and 15.4% higher than 2.0 mg/kg. When the mushrooms were sliced and cooked in water at 95 degrees C for 6 min, 89.1% of the original HCN was lost. When the P. eryngii strains were respectively grown by submerged cultivation in YMB or YMB supplemented with 2.5% glycine for 16 days, HCN content was slightly higher in the latter than in the former for each strain.

Adsorption↗

PubMed2007

Antioxidant constituents in distillation residue of Awamori spirits.

Constituents in a distillation residue of Awamori (millet spirits) and their antioxidant activity are investigated in this study. The supernatant of the distillation residue obtained by centrifugation was partitioned with n-hexane, chloroform, ethyl acetate, and n-butanol against water to afford the corresponding solubles. Among them, n-hexane and chloroform solubles showed higher antioxidant potency than l-ascorbic acid by the bleomycin-Fe method. In chloroform solubles, seven cyclic dipeptides were identified along with ethyl 2-pyrrolidione-5-carboxylate, tyrosol, and ethyl p-hydoroxyphenyllactate. Antioxidant activity of ethyl p-hydoroxyphenyllactate was 4.2 times that of l-ascorbic acid, whereas cyclic dipeptides showed activity 0.89-1.29 times as strong as that of l-ascorbic acid. On the other hand, scavenging effect of cyclic dipeptides against O(2)(-.) and OH(.) by using electron spin resonance was also investigated. In the results, cyclo(l-Ile-l-Pro) showed significantly strong inhibitory effect against OH(.) (95.4% at 2.5 x 10-3 M) and cyclo(l-Phe-l-Pro), cyclo(l-Pro-l-Val), and cyclo(l-Leu-l-Pro) inhibited OH(.) 64.9, 54.1, and 51.0%, respectively, whereas alpha-tocopherol showed 37.7% inhibition, though only a few cyclic dipeptides weakly inhibited O(2)(-.).

Alcoholic Beverages↗

PubMed1999

Dissipation of propiconazole and tebuconazole in peppermint crops (Mentha piperita (Labiatae)) and their residues in distilled oils.

The broad-spectrum, systemic fungicides propiconazole (1) and tebuconazole (2) are used to control rust in peppermint (Mentha piperita L.). An analytical method, using gas chromatography combined with detection by high-resolution mass spectrometry, was developed to allow for the simultaneous monitoring of both pesticides in peppermint leaves and oil. Field trials were established to determine the rate of dissipation of tebuconazole and propiconazole in peppermint crops. Three applications of each fungicide were trialed at two rates (125 and 250 g of active ingredient (ai)/ha). At harvest, 64 days after the final application, propiconazole was detected at levels of 0.06 mg/kg and 0.09 mg/kg of dry weight, and tebuconazole was detected at 0.26 and 0.80 mg/kg dry weight, in identical trials. Rates of dissipation of propiconazole and tebuconazole were lower at a second trial site, where three applications of 125 g/ha ai for each fungicide resulted in residue levels of 0.21 mg/kg for both pesticides, detected 89 days after the last application. Propiconazole and tebuconazole were detected in the distilled oil at levels between 0.02 and 0.05 mg/kg and between 0.011 and 0.041 mg/kg, respectively. Propiconazole had a higher tendency to co-distill with the peppermint oil, with 0.7% of that present in the vegetative material ending up in the oil, compared to 0.09% of tebuconazole.

Fungicides, Industrial↗

PubMed1999

Phenolic constituents, furans, and total antioxidant status of distilled spirits.

The concentrations of 11 phenols and 5 furans were measured in 12 categories of distilled spirits by HPLC methodology, together with the total antioxidant status (TAS) of the same beverages. Ellagic acid was the phenol present in highest concentration in all beverages. Moderate amounts of syringaldehyde, syringic acid, and gallic acid, as well as lesser amounts of vanillin and vanillic acid, were measurable in most samples of whiskey, brandy, and rum but were largely undetectable in gin, vodka, liqueurs, and miscellaneous spirits. 5-(Hydroxymethyl)furfural was the predominant furan in the former three beverages, notably cognac, with 2-furaldehyde the next highest, but these were undetectable in most of the latter beverages. Highest TAS values were given by armagnac, cognac, and bourbon whiskey, all three of which tended toward the highest concentrations of phenols. Negative TAS values were exhibited by rum, vodka, gin, and miscellaneous spirits in line with the low or undetectable phenol concentrations in these beverages. Wood aging is the most likely source of phenols and furans in distilled spirits. Those beverages exposed to this treatment contain significant antioxidant activity, which is between the ranges for white and red wines, with the potential to augment the antiatherosclerotic functions attributable to the ethanol that they contain.

Alcoholic Beverages↗