Total Extractable Material Research Articles

A CP/MAS 13C-NMR study of cellulose fibril aggregation in eucalyptus dissolving pulps during drying and the correlation between aggregate dimensions and chemical reactivity

Abstract Changes in supramolecular properties of cellulose I, namely its lateral fibril aggregate dimension (LFAD), in bleached hardwood acid bisulphite pulp during drying was studied using cross-polarization/magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C-NMR) in combination with spectral fitting. A significant change in aggregate dimensions was noticed when each of the pulp grades were oven dried. The effect of drying was further investigated with pulp samples subjected to different drying methods. A comparison of a harsh oven drying, mild and rapid air drying, and a very mild and slow condition drying showed that the LFAD of the material decreases in the following order: oven drying > air drying > condition drying. The correlation between the total extractable material S10 (%) and LFAD and also the LFAD increment (ΔLFAD in %) are presented and shown to be intimately related. This means that the method of drying influences the size of the fibril aggregate dimensions and depends on the presence of extractable material within the fibre cell wall. Reactivity studies were carried out based on the acetylation of cotton linters and commercial 96α pulp. Results indicate that the initial reaction rate is proportional to the specific surface area of the two cellulose pulp samples. Accordingly, the specific surface area is directly related to initial reactivity of the performed acetylation. We demonstrated that it is possible to control the LFAD and hence specific surface area in laboratory-produced pulps 91α, 92α, and 96α by the drying method. Thus controlling LFAD can probably be one viable route for controlling the initial reactivity of dissolving pulp towards acetylation.

The development of a method for the qualitative and quantitative determination of petroleum hydrocarbon components using thin-layer chromatography with flame ionization detection

An analytical scheme to determine groups of petroleum hydrocarbon compounds in crude oil was developed and used for the qualitative and quantitative characterization of crude oil samples from the Shengli oilfield, the second largest oilfield in China. Crude oil samples were fractionated and analyzed by thin-layer chromatography with flame ionization detection (TLC-FID). Relative standard deviation (RSD) values for retention time, peak height and half peak width were less than 5.2% for all classes of compounds, based on nine independent replicates. The crude oil light fraction was further analyzed by GC–MS and the majority of identified compounds were methyl- or hydro-derivatives of long-chain hydrocarbons and aromatic compounds. The external standard method used in the present study can lower detection limits of petroleum hydrocarbon compound classes to 20.0 mg L −1, and the crude oil concentration in the range of 30 and 35,000 mg L −1 has a high linear correlation ( r 2 > 0.97, P < 0.05) with peak area. A comparison between elution chromatography (EC) and TLC-FID regarding the recovery of petroleum hydrocarbon compounds was carried out with aged crude oil contaminated soils of 50, 80, 200 and 300 mg g −1. The tested TLC-FID method showed a 10% higher recovery for total extractable materials than the reference EC method. The calibration factor was fraction-dependent and varied with the recovery rate of TLC/EC. Regarding the tested extraction procedures, accelerated solvent extraction (ASE) had a higher extraction efficiency for crude oil contaminated soils than Soxhlet and ultrasonic extractions.

Application of Chemometrics to Modeling Produced Water Contamination

:A partial least-squares statistical model was prepared to describe the contamination of produced water by soluble organic compounds. The model incorporated predictor variables used in earlier characterization studies: pH, temperature, pressure, salinity, water-to-oil ratio, and origin of the crude. Response variables included total extractable material and concentrations of aliphatic, aromatic, and polar organic molecules. The model was used to predict the uptake of water-soluble organics under a variety of conditions. The model will be applied to the prediction of hydrocarbon contamination of water produced in offshore drilling.

Complete curve fitting of extraction profiles for estimating uncertainties in recovery estimates.

This paper reports the use of improved numerical approaches to modelling extraction profiles, and shows that the approach substantially reduces statistical prediction uncertainties compared to those obtained on the basis of a three-point extrapolation from the later part of the extraction curve. Numerical fitting of manually obtained polycyclic aromatic hydrocarbon extraction data to a spherical particle diffusion model showed uncertainties typically reduced by a factor of three (with extremes at 1.02 and 770). Application to pressurised fluid extraction study of pelletised poly(vinylchloride) containing 30 mass% di(2-ethylhexyl)phthalate also showed good improvements. However, this high precision data showed small but significant lack of fit resulting in residual correlation and visibly biased prediction (more so than simple extrapolation). Re-fitting and uncertainty estimation using a first-order autoregression approximation to the covariance matrix produced more realistic uncertainty estimates and closer parameter estimates and is accordingly recommended for treating residual correlation from other causes, but did not entirely alleviate the problem. Different shape models (spherical, plane sheet and cylindrical) were applied without accounting fully for fitting error, and particle size effects were eliminated by modelling a simple size distribution. However, an approximate model based on linearly concentration-dependent diffusion coefficient showed excellent fit, confirming concentration-dependence as the most likely cause. This semiempirical model led to an uncertainty in total extractable material, at 0.2% of the total extractable value (with allowance for correlation). This is potentially good enough for recovery estimation and correction in certification of reference materials for validation purposes.

Optimization of Extraction Conditions for Active Components in Hypericum perforatum Using Response Surface Methodology

Optimal conditions for extraction of Hypericum perforatum were determined using response surface methodology. A 3 x 4 x 4 full factorial design representing three extraction temperatures, four extraction times, and four solvent concentrations was executed. The overall extraction efficiency was defined by comparing either the total extractable material weight or the individual component peak area to the peak area of luteolin as internal standard. Of the tested variables, the extraction temperature most significantly affected extraction efficiency. Higher temperatures gave better extraction efficiencies, but high temperature also caused decomposition of hypericin. Within the test range, responses for most variables had local maxima. Optimum ranges of time and concentration for individual variables were overlaid. Considering all variables, optimum ranges for extraction time and extraction solvent concentration (percent ethanol in acetone) were 5.0-6.7 h and 44-74% at 23 degrees C, 5.4-6.9 h and 45-72% at 40 degrees C, and 5.3-5.9 h and 44-69% ethanol in acetone at 55 degrees C, respectively.

The effects of hydrocarbon pollution from a two‐stroke outboard engine on the feeding behaviour of Lythrypnus dalli (Perciformes: Gobidae)

Feeding behaviour (time of attack on flake fish food) in Lythrypnus dalli was measured under pollution concentrations of 2.1 and 4.01mgl−1 total extractable material produced by a two‐stroke outboard engine. The variance of the times increased in pollution versus control treatments for both concentrations. No significant difference was found between the mean times of the control and 2.1 mgl−1 pollution treatments. A significant difference was found between the mean times of the control and pollution treatments for two different tests at 4.01 mgl−1. The combination of the increase in mean time of food attack and the increase of variance indicates that pollution concentrations lower than LD50 levels change feeding behaviour, and thus may indirectly effect the survival of the organism.

Optimization of extraction conditions for active components in Hypericum perforatum using response surface methodology.

Optimal conditions for extraction of Hypericum perforatum were determined using response surface methodology. A 3 x 4 x 4 full factorial design representing three extraction temperatures, four extraction times, and four solvent concentrations was executed. The overall extraction efficiency was defined by comparing either the total extractable material weight or the individual component peak area to the peak area of luteolin as internal standard. Of the tested variables, the extraction temperature most significantly affected extraction efficiency. Higher temperatures gave better extraction efficiencies, but high temperature also caused decomposition of hypericin. Within the test range, responses for most variables had local maxima. Optimum ranges of time and concentration for individual variables were overlaid. Considering all variables, optimum ranges for extraction time and extraction solvent concentration (percent ethanol in acetone) were 5.0-6.7 h and 44-74% at 23 degrees C, 5.4-6.9 h and 45-72% at 40 degrees C, and 5.3-5.9 h and 44-69% ethanol in acetone at 55 degrees C, respectively.

Degradation of petroleum hydrocarbons by facultative anaerobic bacteria under aerobic and anaerobic conditions

Nitrate-reducing bacterial strains ( Pseudomonas sp. BS2201, BS2203 and Brevibacillus sp. BS2202) isolated from petroleum-contaminated soil were capable of degrading petroleum hydrocarbons under aerobic and anaerobic conditions. Under aerobic conditions (a 10-day experiment in liquid media) the strains degraded 20–25% of the total extractable material (TEM), including up to 90–95% of all alkanes analyzed ( n-C 10–C 35). Under anaerobic conditions (a 50-day experiment) these organisms degraded 15–18% of the TEM, 20–25% of some alkanes, and 15–18% of selected polycyclic aromatic hydrocarbons. The strains also degraded saturated hydrocarbons under anaerobic conditions in the absence of nitrates as electron acceptors.

Method for quantifying the fate of petroleum in the environment

Petroleum is a complex mixture of a wide range of hydrocarbon and non-hydrocarbon compounds of various physical and chemical properties. In recent years, the research on the fate of petroleum in the environment has required analytical methods that can provide more detailed information on the components of petroleum than traditional standard methods. The analytical method presented for aqueous, sediment, and soil samples provides several levels of information on petroleum in the environment.The Total Extractable Materials (TEM) analysis provides a gross measure of petroleum in the environment using methylene chloride extraction and gravimetric analysis. Gross composition analysis separates the methylene chloride extract into a saturate hydrocarbon, an aromatic hydrocarbon, and a polar fraction each measured gravimetrically. In contrast, the target compound analysis provides a detailed measure by GC-MS of 62 specific compounds. Normalization to the conservative compound, 17α,2l -(H)Hopane, is incorporated into the method to reduce the effects of sample and site heterogeneity. Quality control and quality assurance procedures are integral parts of these analyses to assure the validity of the resulting data. A sample data set from a biological augmentation product evaluation was used only to illustrate the interpretation of the petroleum chemistry. In this example, conclusions were dependent on the criteria for evaluating the fate of petroleum. As the product evaluation progressed through the petroleum chemistry method, the conclusion on the their effectiveness changed. Therefore, proper interpretation of the petroleum chemistry, which is dependent on the method, is necessary to correctly evaluate the fate of petroleum in the environment.

Acute Toxicity of Estuarine Wetland Sediments Contaminated by Petroleum

A study evaluating sediment toxicity in an estuarine marshland near Houston, Texas, was conducted following a major petroleum pipeline rupture during a flood event. Acute sediment toxicity was measured by performing the Microtox® bioassay 100% Test on elutriates from wet sediment samples collected from experimental plots in the study area. Samples were collected over a seven-month period following the spill. Toxic responses were examined for spatial and temporal relationships within the cove and compared to total extractable materials (TEM), total petroleum hydrocarbon (TPH), and GC-MS quantified total saturates and aromatics and target polycyclic aromatic hydrocarbons (PAHs). Sediment toxicity was elevated near the mouth of the study cove and decreased rapidly with time. Acute toxicity was correlated with TPH and GC-MS quantified saturate concentrations. However, toxicity levels were not correlated with TEM or GC-MS aromatic summations and target PAHs. The rapid decrease in sediment toxicity corresponded with a rapid decrease in oil levels suggesting that the intrinsic recovery of the site was due to acclimated populations of hydrocarbon-degrading microrganisms.

TOXICOLOGICAL MONITORING OF AN OIL-IMPACTED ESTUARINE MARSHLAND

ABSTRACT Toxicological monitoring was conducted on an estuarine marshland in the Houston Ship Channel following a local oil spill. Acute toxicity of petroleum-contaminated sediments, as determined by the Microtox Bioassay, was used to monitor intrinsic recovery of the impacted marsh. Sediment toxicity was determined by performing the Microtox 100% test on elutriates from wet sediment samples collected over a 7-month period following the spill. Toxic responses were examined for spatial and temporal relationships and were compared to various parameters of interest, including total petroleum hydrocarbon (TPH), total extractable materials (commonly referred to as oil and grease [O&amp;G]), and GC/MS-quantified total saturates and aromatics. Toxicity was randomly distributed within the study site and decreased with time. Acute toxicity was correlated with TPH measurements and moderately correlated with GC/MS-quantified saturate concentrations. However, toxicity levels were not correlated with O&amp;G or GC/MS aromatic summations.

Test Method for Extract Able Matter in Elastomeric Seals for Inhalation Aerosol Products

A test method is described for the quantitative determination of total extractable material from elastomeric aerosol seals, and for the reproducible production of a sample of the extractable material. The method was applied by six different laboratories to rubber samples similar to those found in aerosol valves, using solvent systems which may be found in typical inhalation aerosol products. The reproducibility within laboratories was found to be excellent, and in general the agreement between laboratories was good, but close adherence to the protocol was required.

Determination of Lubricating Oil and Unburned Fuel in Diesel Particulates

A method for determining the contribution of lubricating oil and fuel to particulates emitted from diesel engines is described. Methylene chloride extracts of the particulates were separated by silica gel fractionation using hexane, methylene chloride, acetone and methanol. The molecular weight distribution of each fraction was determined using size exclusion chromatography. The speciation of diesel particles into unoxidized oil, oxidized oil, unoxidized fuel and oxidized fuel was determined systematically for a diesel engine modified over a period of more than a year. These modifications significantly affected the total extractable material (12.6-72.3%) and distribution of oil and fuel components. Engine oil was consistently found to be the major contributor to the extractable material, varying from 10 to 60% of the total particulates emitted.

Purification of glycerol dialkyl nonitol tetraether from Sulfolobus acidocaldarius.

A modified procedure for extraction and purification of hydrolyzed archaebacterial lipids is described. Lipids were extracted from Sulfolobus acidocaldarius using a Soxhlet extraction procedure followed by trichloroacetic acid solvent-extraction of the residue. The yield of total extractable material by this protocol was 14% which, after a two-phase wash, yielded 10% lipid. Modifications to the published steps for purifying the subsequently hydrolyzed lipids were developed to purify glycerol dialkyl nonitol tetraether (GDNT). The nearly colorless final macrocyclic product was characterized by TLC, IR, NMR, and mass spectrometry.

Polyuronide Fraction and Soluble and Insoluble Carbohydrates of Orange Peel

1. The whole peel of Valencia oranges and the albedo of navel oranges were separated into alcohol-soluble and alcohol-insoluble fractions by extraction of the fresh material with hot 80% ethyl alcohol. The principal constituents of the two fractions were determined, and some of their chemical properties studied. 2. The alcohol-soluble fraction of the whole peel of Valencia orange and of the albedo of navel orange averaged 57.31% and 55.19%, respectively, of the total dry weights. Soluble sugars accounted for 55.4% of the total extractable material in Valencia peel and for 72.69% in navel albedo. This fraction also contained substances which produced a small amount of carbon dioxide on hydrolysis with 19% hydrochloric acid. This carbon dioxide was probably produced by low polymer galacturonides soluble in hot 80% alcohol. 3. The alcohol-insoluble fraction of Valencia orange whole peel and of navel albedo averaged 42.69% and 44.81%, respectively, of the total dry weights. The sum of the water-soluble and acid-soluble pectic substances (as calcium pectate) of the alcohol-insoluble fraction averaged 39.76% in Valencia peel and 34.87% in navel albedo; the insoluble residues averaged 30.53% and 30.41%, respectively. The undetermined portion consisted of hemicelluloses which contained small amounts of polyuronides and which were rendered soluble by the extraction treatment. 4. The purity of the extracted pectic material (as calcium pectate) was ascertained on each sample by determining contents of carbon dioxide, calcium, and furfural. 5. As the polyuronides yield carbon dioxide quantitatively on hydrolysis with hydrochloric acid, the carbon dioxide values determined are a fair measure of the total pectic substances in the alcohol-insoluble solids. When the carbon dioxide values were accompanied by corresponding values for methoxyl, the degree of methylation of the pectic substances was subsequently calculated by dividing the determined methoxyl by that equivalent to the total carbon dioxide. Methylation in Valencia peel averaged 83.38%, and in navel albedo, 82.39%. 6. The sum of the carbon dioxide in the aqueous extract, acid extract, and residue amounted to 95.20% and 97.47% (mean values) of the total carbon dioxide of the alcohol-insoluble solids in the Valencia orange peel and navel orange albedo, respectively. The total calcium pectate precipitated from the aqueous and acid extracts of Valencia peel yielded 94.12% of the carbon dioxide dissolved by the extractants. The corresponding value for navel albedo was 88.00%. 7. Since the alcohol-insoluble fraction contained the pectic substances, most of the carbon dioxide which could be liberated by hydrolysis with 19% hydrochloric acid, and all the methoxyl groups, occurred in this fraction. The ratio of methoxyl to carbon dioxide was approximately the same in Valencia orange peel and in navel orange albedo. 8. The carbon dioxide equivalent to the sum of the esterified and nonesterified carboxyl groups was equal to the total carbon dioxide of the alcohol-in-soluble fraction obtained on hydrolysis with 19% hydrochloric acid.