Hydrocarbons total petroleum

MICROWAVE-ASSISTED SOLVENT EXTRACTION AND A NEW METHOD FOR ISOLATION OF TOTAL PETROLEUM HYDROCARBONS (TPH) FROM PLANTS WITH COLUMN CHROMATOGRAPHY (SILICA GEL AND ALUMINA) AND DETERMINATION WITH SPECTROFLUOROPHOTOMETRY... 

The efficiencies of total petroleum hydrocarbons (TPH) transfer into various solvents from plants by microwave enhanced process were extracted. 

With this mobile phase colour compounds and carotenoids separated with 15 ml of chloroform (first fraction) and the second fraction with 20ml chloroform contained total petroleum hydrocarbons. At the end Spectrofluorophotometry was employed for quantification of analytes. 

Pure M-hexane is widely used in laboratories as an extractant for nonpolar compounds and in calibrating instruments for analyses of volatile organic compounds (VOC) or total petroleum hydrocarbons (TPH) (Kanatharana et al. 1993). Since such analyses may require very high levels of purity, laboratories sometimes carry out their own fractional distillation or other pretreatment-purification procedures to remove petroleum hydrocarbon impurities found in commercially available grades of M-hexane (Kanatharana et al. 1993). See Chapter 6 for more information about testing for -hexane. 

Heath JS, Koblis K, Sager SL, et al. 1993. Risk assessment for total petroleum hydrocarbons. In Kostecki PT, Calabrese EJ, eds. Hydrocarbon contaminated soils and groundwater. Vol. 3,267-301. Chelsea, MI Lewis Publishers. 

California Department of Health Services, 1989, Total Petroleum Hydrocarbons (TPH) Analysis — Gasoline and Diesel In California Water Resources Control Board Leaking Underground Fuel Tank (LUFT) Manual, Appendix C. 

While the 8-h test results indicated a total petroleum hydrocarbons (TPH) recovery rate of 10 lb/day, this rate probably will not continue. Estimation of the expected long-term recovery rate of TPH by this short-term test data is not a reliable exercise. The data demonstrate the applicability of SVE as a recovery system, but further testing or detailed computer modeling was recommended prior to final design. 

As a resnlt of the wide variety of chemicals in petroleum and in petroleum products, it is not practical to measure each one separately. After an incident, it is more usual to measure the amount of total petroleum hydrocarbons at the site. The term total petroleum hydrocarbons (TPHs) is used environmentally to describe the family of several hundred chemical compounds that originally come from petroleum (Weisman, 1998). 

Chemicals that may be included in the total petroleum hydrocarbons are hexane, heptane (and higher-molecular-weight homologs), benzene, toluene, xylenes (and the higher-molecular-weight homologs), and naphthalene as well as the constituents of other petroleum products, such as gasoline and diesel fuel. It is likely that samples of the total petroleum hydrocarbons collected at a specific site wiU contain only some, or a mixture, of these chemicals. 

In addition, the amount of total petroleum hydrocarbons is the measurable parameter of petroleum-based hydrocarbon in an enviromnental medium, whether it is air, water, or land. It is thus dependent on analysis of the medium in which it is found, and since it is a measured, gross quantity without identification of its constituents, the total petroleum hydrocarbons data still represent a mixture. Thus, the data derived from measmement of the petroleum hydrocarbons in a particular enviromnent is not a direct indicator of risk to humans or to the environment. 

Petroleum products themselves are the source of the many components but do not adequately define total petroleum hydrocarbons. However, the composition of petroleum products assist in understanding the hydrocarbons that become environmental contaminants, but any ultimate exposure is also determined by how the product changes with use, by the nature of the release, and by the hydrocarbon s environmental fate. When petroleum products are released into the environment, changes occur that affect their potential effects significantly. Physical, chemical, and biological processes change the location and concentration of hydrocarbons at any particular site. 

Analysis for total petroleum hydrocarbons (EPA Method 418.1) provides a one-number value of the petroleum hydrocarbons in a given environmental medium. It does not, however, provide information on the composition (i.e., individual constituents) of the hydrocarbon mixture. The amount of hydrocarbon contaminants measured by this method depends on the ability of the solvent used to extract the hydrocarbon from the environmental media and the absorption of infrared light (infrared spectroscopy) by the hydrocarbons in the solvent extract. The method is not specific to hydrocarbons and does not always indicate petroleum contamination, since humic acid, a nonpetroleum material and a constituents of many soils, can be detected by this method. 

An important feature of the analytical methods for the total petroleum hydrocarbons is the use of an equivalent carbon number index (EC). This index represents equivalent boiling points for hydrocarbons and is the physical characteristic that is the basis for separating petroleum (and other) components in chemical analysis. 

Weisman, W. (Ed.). 1998. Analysis of Petroleum Hydrocarbons, Environmental Media Total Petroleum Hydrocarbon Criteria Working Group Series. Amherst Scientific Publishers, Amherst, MA. 

There are many recommended sampling protocols (Table 6.2). The sampling methods used for petroleum hydrocarbons are generally thought of as methods for determination of the total petroleum hydrocarbons. In part due to the complexity of the components of the total petroleum hydrocarbons fractions, little is known about their potential for health or environmental impacts. As gross measures of petroleum contamination, the total petroleum hydrocarbons data simply show that petroleum hydrocarbons are present in the sampled media. Measured total petroleum hydrocarbons values suggest the relative potential for human exposure and therefore the relative potential for human health effects. 

Method 1664 n-Hexane Extractable Material (HEM) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM) by Extraction and Gravimetry (Oil and Grease and Total Petroleum Hydrocarbons) Monitoring Trace Metals at Ambient Water Quality Criteria Levels Briefing Book... 

Once the sample preparation is complete, there are several approaches to the analysis of petroleum constituents in the water and soil (1) leachability or toxicity of the sample, (2) the amounts of total petroleum hydrocarbons in the sample, (3) petroleum group analysis, and (4) fractional analysis of the sample. These methods measure different petroleum constituents that might be present in petroleum-contaminated environmental media. 

Total petroleum hydrocarbon (TPH) (Chapter 4) analyses (Tables 7.1 and 7.2) are conducted to determine the total amount of hydrocarbon present in the environment. There are a wide variety of methods for measurement of the total petroleum hydrocarbon in a sample, but analytical inconsistencies must be recognized because of the definition of total petroleum hydrocarbons and the methods employed for analysis (Rhodes et al., 1994). Thus, in practice, the term total petroleum hydrocarbon is defined by the analytical method since different methods often give different results because they are designed to extract and measure slightly different subsets of petroleum hydrocarbons. 

Table 7.1. Summary of Analytical Methods for Determining the Total Petroleum Hydrocarbons in a Sample... 

The analysis for the total petroleum hydrocarbons (TPHs) in a sample as a means of evaluating petroleum-contaminated sites is also an analytical method in common use. The data are used to establish target cleanup levels for soil or water by regulatory agencies in the United States and in many other countries. 

The data obtained by the analysis have become key remediation criteria and it is essential that the environmental analyst (and others who may use the data) be knowledgeable about the various analytical methods. It is also important to know that minor method deviations may be found from region to region. For example, in terms of nomenclature, itself a complex and often ill-defined area of petroleum science (Chapter 1) (Speight, 1999), the analytical methods may refer to total petroleum hydrocarbons as mineral oil, hydrocarbon oil, extractable hydrocarbon, and oil and grease. 

Thus, as often occurs in petroleum science (Speight, 1999), the definition of total petroleum hydrocarbons depends on the analytical method used because the total petroleum hydrocarbons measurement is the total concentration of the hydrocarbons extracted and measured by a particular method. The same sample analyzed by different methods may produce different values. For this reason, it is important to know exactly how each determination is made since interpretation of the results depends on understanding the capabilities and limitations of the method. If used indiscriminately, measurement of the total petroleum hydrocarbons in a sample can be misleading, leading to an inaccurate assessment of risk. 

There are several reasons why the data for total petroleum hydrocarbons do not provide ideal information for investigating sites and establishing target cleanup criteria. For example, use of the term total petroleum hydrocarbons suggests that the analytical method measures the combined concentration of all petroleum-derived hydrocarbons, thereby giving an accurate indication of site contamination. But this is not always the case. Furthermore, target cleanup levels based on total petroleum hydrocarbons concentrations implicitly assume (1) that the data are an accurate measurement of petroleum-derived hydrocarbon concentration, and (2) the data also indicate the level of risk associated with the contamination. These assumptions are not correct due to many factors, including the nonspecificity of some of the methods used and the complex nature of petroleum hydrocarbons and their interaction with the environment over time. 

Some methods measure more compounds than other methods because they employ more rigorous extraction techniques or more efficient solvents for the extraction procedure(s). Other methods are subject to interferences from naturally occurring materials such as animal and vegetable oils, peat moss, or humic material, which may result in artificially high reported concentrations of the total petroleum hydrocarbons. Some methods use cleanup steps to minimize the effect of nonpetroleum hydrocarbons, with variable success. Ultimately, many of the methods are limited by the extraction efficiency and the detection limits of the instrumentation used for measurement. 

Although the utility of data for total petroleum hydrocarbons for risk assessment is minimal, it is an inexpensive tool that can be used for three purposes (1) determining if there is a problem (2) assessing the severity of contamination, and (3) following the progress of a remediation effort. If the data for the... 

There are many analytical techniques available that measure total petroleum hydrocarbon concentrations in the environment, but no single method is satisfactory for measurement of the entire range of petroleum-derived hydrocarbons. In addition, and because the techniques vary in the manner in which hydrocarbons are extracted and detected, each method may be applicable to the measurement of different subsets of the petroleum-derived hydrocarbons present in a sample. The four most commonly used total petroleum hydrocarbon analytical methods include (1) gas chromatography (GC), (2) infrared spectrometry (IR), (3) gravimetric analysis, and (4) immunoassay (Table 7.1) (Miller, 2000, and references cited therein). 

Gas chromatographic methods are currently the preferred laboratory methods for measurement of total petroleum hydrocarbon measurement because they detect a broad range of hydrocarbons and provide both sensitivity and selectivity. In addition, identification and quantification of individual constituents of the total petroleum hydrocarbon mix is possible. 

Methods based on gravimetric analysis (Table 7.2) are also simple and rapid, but they suffer from the same limitations as those of infrared spectrometric methods (Table 7.2). Gravimetric-based methods may be useful for oily sludge and wastewaters, which will present analytical difficulties for other, more sensitive methods. Immunoassay methods for the measurement of total petroleum hydrocarbon are also popular for field testing because they offer a simple, quick technique for in situ quantification of the total petroleum hydrocarbons. 

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