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PubMed2004

Composition of corn and distillers dried grains with solubles from dry grind ethanol processing.

Increase in the demand for ethanol has resulted in growth in the dry grind (DG) ethanol industry. In DG processing, the whole corn kernel is fermented, resulting in two main coproducts, ethanol and distillers dried grains with solubles (DDGS). Marketing of DDGS is critical to the economic stability of DG plants. The composition of DDGS can vary considerably; this reduces market value. Factors that cause variation in composition need to be evaluated. The objective was to determine the relationship between composition of corn and composition of DDGS. Samples of corn and DDGS were obtained from a DG ethanol plant and analyzed for protein, fat, starch and other nutrients. Concentrations of protein, fiber and starch were similar to published data for corn but were higher for DDGS. Coefficients of variation for protein fat and fiber concentrations were similar for corn and DDGS. There were no significant correlations between concentrations of components in corn and those in DDGS. Variation in the composition of DDGS was not related to variation in corn composition and probably was due to variation in processing streams or processing techniques. This implies that reducing the variation in composition of DDG will require modification of processing strategies.

Biotechnology↗

PubMed2004

An efficient sequence for the preparation of small secondary amine hydrochloride salts for focused library generation without need for distillation or chromatographic purification.

Collections of small secondary amines for compound library generation can be efficiently prepared by amide reduction using BH(3)-THF or Red-Al followed by brief methanolysis, trapping with di-tert-butyl dicarbonate, and deprotection with 4M HCl in dioxane. The sequence requires no chromatography or distillation and provides multi-gram quantities of pure HCl salts in a short time.

Amines↗

PubMed2005

Determination of alkylphenolic residues in fresh fruits and vegetables by extractive steam distillation and gas chromatography-mass spectrometry.

This study describes a simple and sensitive method for determining the alkylphenolic compounds, 4-tert-octylphenol (4-t-OP), 4-nonylphenol isomers (4-NPs), and their monoethoxylates (4-t-OP1EO and 4-NP1EOs), in fresh fruits and vegetables. The method involves extracting a sample by a modified Nielson-Kryger steam distillation extraction using n-hexane for 1 h. The alkylphenolic compounds were identified and quantitated by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Various pH values and amounts of NaCl added to the sample solution were evaluated as extraction conditions. The quantitation limit of this method was less than 0.2 ng/g in 10 g (fresh weight) of sample. Recovery of alkylphenolic compounds in spiked samples exceeded 64% while R.S.D. ranged from 1.0 to 9.8%. Alkylphenolic residues were detected in fresh fruits and vegetables at concentrations of 4-NPs and 4-t-OP from n.d. to 16 ng/g and from n.d. to 4.8 ng/g (fresh weight), respectively. NP1EO and OP1EO were always below the quantitation limit.

Fruit↗

PubMed2006

Comparison of micro-scale simultaneous distillation-extraction and stir bar sorptive extraction for the determination of volatile organic constituents of grape juice.

Traditional micro-scale simultaneous distillation-extraction (SDE) and stir bar sorptive extraction (SBSE) were compared for their effectiveness in the extraction of volatile organic compounds in a synthetic grape juice and a real grape juice (Huxelrebe, a variety of half Muscat ancestry) from an English vineyard. The novel immersion-mode SBSE method, using stir bars with PDMS sorbent, was optimised using the synthetic grape juice. Although mean percent relative recoveries and reproducibilities (%CV) of the SBSE method were inferior to SDE (28.4 and 8.5%, respectively, against 86.9 and 6.3%), the former method proved to be significantly more sensitive: 126 aroma compounds in Huxelrebe grape juice were identified using SBSE, against 98 using SDE. This allowed the identification of a number of volatile components that have not been reported previously in the juice or wine from the grapes of Muscat varieties.

Beverages↗

PubMed2006

Immobilization and enzymatic activity of glucose oxidase on polystyrene surface modified with ozone aeration and UV irradiation in distilled water and/or aqueous ammonia solution.

Adsorption condition and enzymatic activity of glucose oxidase (GOD) on polystyrene (PS) film surfaces modified with ozone aeration and UV irradiation (O3/UV) treatment were investigated. The total amount of GOD immobilized on the PS film modified with the O3/UV treatment in distilled water (PS-W film) was approximately twice as large as that on the film treated in an aqueous ammonia solution (PS-A film), whereas the specific activity of GOD on the PS-A film was four times higher than that on the PS-W film. In contrast, no enzymatic activity of GOD on the non-treated PS film was observed because of irreversible denaturation of the adsorbed GOD. We therefore conclude that the PS films modified by the O3/UV treatment in the aqueous media are effective in immobilizing GOD.

Adsorption↗

PubMed2005

Hardness and diametral tensile strength of a hybrid composite resin polymerized with different modes and immersed in ethanol or distilled water media.

OBJECTIVES: The aim of this in vitro study was to evaluate the microhardness and diametral tensile strength of a hybrid composite resin (Z250, 3M ESPE) polymerized with four different modes of light exposure and immersed in two different media. METHODS: Composite resin specimens were randomly polymerized according to the experimental groups (conventional, 550 mW/cm(2)/30 s; soft start, 300 mW/cm(2)/10 s + 550 mW/cm(2)/20 s; high intensity, 1060 mW/cm(2)/10 s; pulse delay, 550 mW/cm(2)/1 s + 60 s of waiting time + 550 mW/cm(2)/20 s) and immersed in one of two media (distilled water or absolute ethanol) for 24 h. After that, microhardness (M) and diametral tensile strength (DTS) tests were performed. RESULTS: For DTS, there were no statistical differences among the polymerization modes, however, ethanol medium groups presented statistically lower DTS (p < 0.05) than water medium. For the M test, samples immersed in ethanol medium presented lower M for almost all groups. Conventional mode presented higher M values for the groups immersed in water medium. In ethanol medium, conventional and pulse delay groups presented higher M values, statistically different (p < 0.05) from the high intensity group. For all experimental conditions, the top surface showed higher M than the bottom surface. SIGNIFICANCE: Different polymerization modes can be related to the different polymer structures formed, and consequently with different physical properties of resin composite. The immersion media can alter the physical properties of resin composites of different polymer structures.

Composite Resins↗

PubMed2006

Performance evaluation of a mesophilic (37 degrees C) upflow anaerobic sludge blanket reactor in treating distiller's grains wastewater.

The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor treating distiller's grains wastewater was investigated for 420 days at 37 degrees C. After a successful start-up, 80-97.3% chemical oxygen demand (COD) removal efficiencies were achieved at hydraulic retention times (HRT) of 82-11h with organic loading rates (OLR) of 5-48.3kgCODm(-3)d(-1). The biogas mainly consisted of methane and carbon dioxide, and the methane and carbon dioxide content in the biogas was 57-60 and 38-41%, respectively. The yield coefficient of methane production was 0.3182lCH(4)g(-1)COD removed until OLR at 33.3kgCODm(-3)d(-1), but afterwards began to decrease. The volatile fatty acid (VFA) in the effluent mainly consisted of acetate and propionate, accounting for more than 95% of total VFA as COD, and other VFA was detected at insignificant concentrations. The mesophilic granules developed in this study showed an excellent specific methanogenic activity (SMA) at 0.91 and 1.12gmethaneCODg(-1)VSS(-1)d(-1) using sucrose and acetate as individual substrates on day 200, respectively.

Bioreactors↗

PubMed2006

Development of gas chromatography-mass spectrometry with microwave distillation and simultaneous solid-phase microextraction for rapid determination of volatile constituents in ginger.

In this study, gas chromatography-mass spectrometry (GC-MS) following microwave distillation and solid-phase microextraction (MD-SPME) was developed for the analysis of essential oil compounds in fresh ginger. In the proposed method, the isolation, extraction and concentration of volatile components in ginger were carried out in one single step, using the MD-SPME technique, and the analytes on the SPME fiber were analyzed by GC-MS. Some parameters, including SPME fiber coating, microwave power and irradiation time, were optimized. The optimal experiment parameters obtained were: 65 microm PDMS/DVB SPME fiber, a microwave power of 400 W and an irradiation time of 2 min. To demonstrate its feasibility, MD-SPME was compared with conventional SPME for the extraction of essential oil compounds in fresh ginger. Using MD-SPME followed by GC-MS, 54 compounds were separated and identified in ginger, which mainly included geranial (5.25%), zingiberene (15.48%), beta-sesquiphellandrene (5.54%) and beta-phellandrene (22.84%), whereas only 39 compounds were separated and identified by conventional SPME followed by GC-MS. The relative standard deviation (R.S.D.) values of less than 10% show that the proposed method has good repeatability. The result show that MD-SPME, followed by GC-MS, is a simple, rapid, solvent-free method for the determination of volatile compounds in ginger.

Gas Chromatography-Mass Spectrometry↗

PubMed2006

Comparison of distillation and ultrasound-assisted extraction methods for the isolation of sensitive aroma compounds from garlic (Allium sativum).

A comparative study of traditional simultaneous distillation extraction (SDE), microwave assisted hydrodistillation extraction (MWHD) and ultrasound-assisted extraction (USE) is presented, for the extraction of essential oils from fresh garlic (Allium sativum) cloves. Each method is evaluated in terms of qualitative and quantitative composition of the isolated essential oil. The highly reactive sulfur molecules of the garlic volatile fraction show variable response to the different isolation methods. The application of ultrasound for the extraction of the essential oil is considered to cause a lesser damage of thermal-sensitive molecules, thus, providing a better approach of the compounds primarily responsible for the characteristic odor and taste of freshly chopped garlic. All heat-involving isolation procedures have been shown to differentiate the volatile-fraction profile as analyzed by GC-MS. Especially when grouping the compounds into cyclic and acyclic, the percentage concentrations drop from 77.4% to 8.7% for the acyclic while that of the cyclic compounds increase from 4.7% to 70.8%. The observed fact may be attributed to the effect of the heat applied, which changes from harsh thermal treatment (SDE) to short time thermal (MWHD) and room-temperature isolation (USE). The use of USE proves to be crucial in order to provide reliable insight into garlic's chemistry.

Chemical Fractionation↗

PubMed1986

Pulmonary fibrosis in cable plant workers exposed to mist and vapor of petroleum distillates.

Twenty-five cable plant workers exposed to mists and vapors of mineral oils and kerosene for 5-35 years have been investigated in a cross-sectional, matched pairs study. The exposed cohort and the referents were examined by radiology, pulmonary function measurements, and a questionnaire for symptoms of respiratory disease. Lung tissue from a deceased worker with 35 years of exposure was investigated by histopathologic methods and by scanning electron microscopy. Exposure measurements were performed by personal sampling. Previous employment and smoking habits were recorded for all subjects. An increased prevalence of slight basal lung fibrosis was found in chest films of the exposed workers. Pulmonary fibrosis was confirmed histopathologically. A moderately decreased vital capacity (VC) and forced expiratory volume (FEV1) was found. Oil mist was measured to time-weighted average levels of 0.15-0.30 mg/m3 with short-term vapor exposure of up to 4000 mg/m3. It is concluded that mists and vapors from petroleum distillates are the most probable causes of the findings.

Adult↗

PubMed2005

Nonintrusive frequency analysis for variable pairing on a distillation column.

This paper describes a nonintrusive plant analysis technique for variable pairing that relies on power spectrum frequency analysis. The development of the method is described and guidelines for the implementation of the method are presented. Information gathered from the frequency analysis is used in variable pairing to ensure minimal impacts from unmeasured disturbances. Specifically, the nested epsilon decomposition method for variable pairing is used. This nonintrusive analysis method is implemented on a pilot plant distillation column. The results of the pilot plant test are used in the decoupling of a multiloop control system.

Journal Article↗

PubMed2000

Analysis of polycyclic aromatic hydrocarbons, phenols and aromatic amines in particulate phase cigarette smoke using simultaneous distillation and extraction as a sole sample clean-up step.

Polycyclic aromatic hydrocarbons (PAHs), phenols and aromatic amines can be analyzed in particulate phase mainstream cigarette smoke using simultaneous distillation and extraction (SDE) as a unique sample clean-up step. All analytes are determined from the same smoke sample using GC-MS. The smoke from 20 cigarettes is collected on a Cambridge smoke pad where a mixture of internal standards is added. The Cambridge smoke pad is extracted in a SDE apparatus using water-CH2Cl2. The SDE extract is analyzed directly for PAHs, for phenols after silylation, and for amines after derivatization with heptafluorobutyric anhydride. Excellent results in agreement with data reported in the literature are obtained by this procedure.

Amines↗

PubMed2001

Comparison of simultaneous distillation extraction and solid-phase microextraction for the determination of volatile flavor components.

Traditional simultaneous distillation extraction (SDE) and solid-phase microextraction (SPME) techniques were compared for their effectiveness in the extraction of volatile flavor compounds from various mustard paste samples. Each method was used to evaluate the responses of some analytes from real samples and calibration standards in order to provide sensitivity comparisons between the two techniques. Experimental results showed traditional SDE lacked the sensitivity needed to evaluate certain flavor volatiles, such as 1,2-propanediol. Dramatic improvements in the extraction ability of the SPME fibers over the traditional SDE method were noted. Different SPME fibers were investigated to determine the selectivity of the various fibers to the different flavor compounds present in the mustard paste samples. Parameters that might affect the SPME, such as the duration of absorption and desorption, temperature of extraction, and the polarity and structure of the fiber were investigated. Of the various fibers investigated, the PDMS-DVB fiber proved to be the most desirable for these analytes.

Chromatography, Liquid↗

PubMed2002

Supercritical carbon dioxide extraction of volatiles from spices. Comparison with simultaneous distillation-extraction.

Supercritical fluid extraction (SFE) and simultaneous distillation-extraction (SDE) were used to extract the essential oils from three different spices (oregano, basil, and mint), and a comparative study of extracts obtained using SFE and SDE is presented. Temperature and pressure for the SFE extraction were optimized prior to the experimental extractions. The extracts obtained using the two methods were very similar in composition, but SFE yielded better relative standard deviations and avoided the thermal degradation or solvent contamination of samples.

Carbon Dioxide↗

PubMed1975

Gas chromatography of volatile fatty acids. Method involving separation from biological material by vacuum distillation.

A method is described for the quantitation of C2-C5 volatile fatty acids present in biological tissues. It involved recovery of the acids from their biological matrix by vacuum micro-distillation at room temperature, followed by gas phase separation of aqueous solutions on orthophosphoric acid-modified Phasepak Q columns. The subsequent gas chromatographic procedure resolved iso from normal isomers and showed a linear response for each volatile acid over the range 10-400 ng. There was no evidence of ghosting, isomer peak broadening, or peak tailing. Relative molar response values were shown to be linear with carbon number for all the volatile fatty acids studied.

Carbon↗

PubMed1991

Foam counter-current chromatography of bacitracin. II. Continuous removal and concentration of hydrophobic components with nitrogen gas and distilled water free of surfactants or other additives.

Foam counter-current chromatography has been successfully applied to continuous removal and concentration of hydrophobic bacitracin (BC) components from a large volume solution using nitrogen gas and distilled water free of surfactants or other additives. The experiment was initiated by introducing nitrogen at the head inlet of the coil rotated at 500 rpm. Then, a 2.5-1 volume of the sample solution containing BC at 50 ppm was continuously introduced into the middle portion of the coil at 1.5 ml/min. The hydrophobic components produced a thick foam which was carried with the gas phase and collected from the tail end of the coil while other components stayed in the liquid stream and eluted from the head outlet of the coil. High-performance liquid chromatographic analysis of the foam fraction revealed that the degree of enrichment increased with hydrophobicity of the BC components. BC-A and -F were enriched 1400 and 2260 times, respectively, compared with the original concentration in the sample solution. These results clearly indicate that the present method will be quite effective for detection and/or isolation of a small amount of natural products present in a large volume of aqueous solution.

Bacitracin↗

PubMed1997

Qualitative and quantitative high-performance liquid chromatographic analysis of aldehydes in Brazilian sugar cane spirits and other distilled alcoholic beverages.

A study is presented on the high-performance liquid chromatographic analysis of eighteen aldehydes in Brazilian sugar cane spirits and other international brandies. The aldehydes were separated by reversed-phase high-performance liquid chromatography as 2,4-dinitrophenylhydrazones (DNPHs). A very good chromatographic separation was achieved for eighteen different aldehyde-DNPHs. The proposed methodology is quite simple and not very time-consuming. Ten aldehydes were identified in 75 beverages and quantified using the external standard method with UV detection at 365 nm. A detailed knowledge of the aldehyde content should significantly contribute to improving the quality control of distilled spirits.

Alcoholic Beverages↗

PubMed2000

Determination of phenols using simultaneous steam distillation-extraction.

Simultaneous distillation-extraction was proposed as a preconcentration step for the determination of phenol and its derivatives in aqueous and soil samples. Detection limits of 0.01 mg l(-1) (water) and 0.1 mg kg(-1) (soil) were achieved by gas chromatography-flame ionization detection. The described preconcentration procedure was applied for the primary study of the adsorption equilibrium in a water-soil system serving as a model of phenol behaviors in the environment.

Chromatography, Gas↗