Extraction sediment samples

Extraction of sediment samples. Prior to extraction, sediment samples were freeze-dried and homogenized. Approximately 10 g of dried sediment were placed in a preextracted thimble, and a small piece of silanized glass wool was placed in the thimble on top of the sample to prevent sediment parts from leaving the thimble. The thimble was placed in a Soxhlet setup and extract for 16 h (overnight) with 200 ml hexane/acetone (3/1 v/v). The extracts were concentrated in the rotation evaporator until approximately 5 ml (/ = 0.05 bar T = 40°C) of extract remained. If the extraet still contained solid particles, the extract was filtered with diatomaceous earth or sodium sulfate. The extract was transferred to a diatomaceous earth- or sodium sulfate-filled funnel and flushed with 10 ml hexane. The eluted extract was evaporated again in the rotary evaporator until approximately 5 ml of extract remained. The extract was transferred to a cleaned glass tube and concentrated until near dryness. The dried extract was finally redissolved in 3 ml hexane. 

Cleanup of sediment samples. The extracted sediment samples were cleaned up using a multilayer column. The multilayer glass column consisted of the following materials (from top to bottom) 1 cm water-free sodium sulfate, 1 g silica, 7 g 44% sulfuric acid on silica, 1 g silica, 2 g 33% sodium hydroxide on silica, 1 g silica, 1.5 g 10% silver nitrate on silica, and a small piece of silanized glass wool. After addition of each layer, the column was compacted by tapping... 

Before the extraction, sediment samples are dried by homogenization with anhydrous sodium sulphate or by air-drying. " ... 

This somewhat lengthy experiment provides a thorough introduction to the use of GG for the analysis of trace-level environmental pollutants. Sediment samples are extracted by sonicating with 3 X 100-mL portions of 1 1 acetone hexane. The extracts are then filtered and concentrated before bringing to a final volume of 10 mL. Samples are analyzed with a capillary column using a stationary phase of 5% phenylmethyl silicone, a splitless injection, and an EGD detector. 

Figure 15-12 is a schematic illustration of a technique known as acid volatile sulfides/ simultaneously extracted metals analysis (AVS/SEM). Briefly, a strong acid is added to a sediment sample to release the sediment-associated sulfides, acid volatile sulfides, which are analyzed by a cold-acid purge-and-trap technique (e.g., Allen et ai, 1993). The assumption shown in Fig. 15-12 is that the sulfides are present in the sediments in the form of either FeS or MeS (a metal sulfide). In a parallel analysis, metals simultaneously released with the sulfides (the simultaneously extracted metals) are also quantified, for example, by graphite furnace atomic absorption spectrometry. Metals released during the acid attack are considered to be associated with the phases operationally defined as "exchangeable," "carbonate," "Fe and Mn oxides," "FeS," and "MeS."... 

Sediment Extraction of sample with organic solvent derivatize extract to the diacetate GC/ECD 0.005B0.01 pg/g (ppm) No data Musial et al. 1976... 

Sediment soil Extract of sample with methylene chloride acetone (1 1) clean-up extract using Florisil column GC/ECD 0.002 pg/g (ppm) ( "endosulfan) 0.004 pg/g ( "endo-sulfan) 0.004 pg/g (endosulfan sulfate) No data Marsden et al. 1986... 

Organic solvents or mixtures of water and solvents such as acetone or water-acetone are commonly used to extract chemicals from sediment samples as for upland soil. An analysis of sediment, collected from waterways or extremely low Eh paddies, frequently requires the removal of sulfur-containing species, although there is little interference from sulfur if the sediments are in a not very reductive condition. Reduced copper and silver nitrate columns are usually used for the removal, but these procedures are not always successful. Recovery studies could be needed to confirm an interference with sulfur. 

DF = dilution factor (60 mL extract/12 mL aliquot = 5) used for soil and sediment samples... 

Sediments Sample leached with HNO3/HF, filtered, purified by KL-HDEHP resin columns, solvent extracted, and electrodeposition a -Spectroscopy No data 95-99% Guogang et al. 1998... 

Obtaining consistent chromatograms of aqueous extracts provides a means of characterizing the presence of a hydrilla-growth inhibitor in natural waters (19). Some examples are provided in Table II, where the location of the second fraction is indicated as percentage of the programmed run. Three different sediment samples were compared for Lake Starvation with consistent results. The fraction obtained for the extract of Lake White Trout is similar to the fraction for Lake Starvation. Hydrilla disappeared from Lake Kerr (located in Marion County, Florida, and the sediment obtained at the time yielded an aqueous extract that appears to contain the hydrilla inhibitor. 

Mineral Oil Hydraulic Fluids. Methods are available for analysis of the hydrocarbon components of mineral oil hydraulic fluids (predominantly straight and branched chain alkanes) in environmental samples. Some of these methods are summarized in Table 6-3. In general, water and sediment samples are extracted with a suitable solvent in a Soxhlet extractor (for solid samples) or in separatory funnel or shake flask (for liquid samples) (Bates et al. 1984 Peterman et al. 1980). The extract is cleaned up on silica gel or Florisil columns using a nonpolar solvent to elute the nonpolar alkanes. Analysis is usually performed by GC/MS (Bates et al. 1984 Kawamura and Kaplan 1983 Peterman et al. 1980). Method performance has not been reported, although 82% recovery of aliphatic hydrocarbons was reported for rainwater (Kawamura and Kaplan 1983). 

Glausch, A., Blanch, G.P., Schurig, V. (1996). Enantioselective analysis of chiral polychlorinated biphenyls in sediment samples by multidimensional gas chromatography-electron-capture detection after steam distillation-solvent extraction and sulfur removal. J. Chromatogr. A 723, 399 104. 

Fig. 3. Cu concentration in catchment outlet sediment samples after MMI extraction.

Miller DN, Bryant JE, Madsen EL, Ghiorse WC. Evaluation and optimization of DNA extraction and purification procedures for soil and sediment samples. Appl. Environ. Microbiol. 1999 65 4715 1724. 

In the 1990s, Pawliszyn [3] developed a rapid, simple, and solvent-free extraction technique termed solid-phase microextraction. In this technique, a fused-silica fiber is coated with a polymer that allows for fast mass transfer—both in the adsorption and desorption of analytes. SPME coupled with GC/MS has been used to detect explosive residues in seawater and sediments from Hawaii [33]. Various fibers coated with carbowax/divinylbenzene, polydimethylsiloxane/divinylbenzene, and polyacrylate are used. The SPME devices are simply immersed into the water samples. The sediment samples are first sonicated with acetonitrile, evaporated, and reconstituted in water, and then sampled by SPME. The device is then inserted into the injection port of the GC/MS system and the analytes thermally desorbed from the fiber. Various... 

EPA Method 7063 Arsenic and selenium in sediment samples and extracts by ASV... 

In Fig. 1.6 (a) is shown a partial chromatogram of a complex mixture of chlorinated biphenyls extracted from a sediment sample. 

Hennig [40] has applied ultraviolet spectroscopy to the determination of aromatic constituents of residual fuel oil in hexane extracts of marine sediment samples. Examination of the ultraviolet spectra of samples of an oil pollutant from a beach and crude oil, at various concentrations, revealed strong absorption maxima at approximately 228nm and 256nm. The ratio of the peak heights at these wavelengths is constant for a particular oil, and is independent of concentration. These permit quantitative analysis of sediment samples many months after an oil spill. 

The ultraviolet absorption spectra of extracts of oil-contaminated sediment samples and unpolluted beach are shown in Fig. 2.3. Levy [41]... 

The phthalate levels of the sediment samples should actually be regarded as minimum values, since only the amount of extractable phthalates has been determined. Eglinton et al. [3] report that some organic pollutants in sediments may be converted into insoluble complexes, such as humates. On the other hand, data by Cifrulak [4] suggest that the use of a methanol-containing solvent mixture, rather similar to the one employed by Schwartz et al. [2], effectively removes all phthalates from sediment and soil samples. 

Dreier et al. [44] determined sterols in lacustrine sediments. Samples of wet lacustrine sediments were heated under anoxic conditions at 150, 175, 200 and 250°C for five days at 175°C for five days with influx of potassium hydroxide and methanol to remove sterols and at 175°C for 12, 18, 24 and 48h, after which extraction was performed. Heating the sediment increased the amounts of extractable sterols provided that the temperature did not exceed 200°C, because degradation became rapid above that temperature. The behaviour of sterol ketones was similar, but the temperature limit was slightly higher. The various levels of the sterols extracted are tabulated 4-methylsterols had a high stability towards thermal degradation under the conditions used. 

Lee [42] determined pentachlorophenol and 19 other chlorinated phenols in sediments. Acidified sediment samples were Soxhlet extracted (acetone-hexane), back extracted into potassium bicarbonate, acetylated with acetic anhydride and re-extracted into petroleum ether for gas chromatographic analysis using an electron capture or a mass spectrometric detector. Procedures were validated with spiked sediment samples at 100,10 and lng chlorophenols per g. Recoveries of monochlorophenols and polychlorophenols (including dichlorophenols) were 65-85% and 80-95%, respectively. However, chloromethyl phenols were less than 50% recovered and results for phenol itself were very variable. The estimated lower detection limit was about 0.2ng per g. 

Goerlitz and Law [59] determined chlorinated insecticides in sediment and bottom material samples, which also contained polychlorobiphenyls by extracting the sample with acetone and hexane. The combined extracts were passed down an alumina column. The first fraction (containing most of the insecticides and some polychlorinated biphenyls and polychlorinated naphthalenes) was eluted with hexane and treated with mercury to precipitate sulphur. If the polychlorinated hydrocarbons interfered with the subsequent gas chromatographic analysis, further purification on a silica gel column was necessary. 

Tobin et al. [14] give details of two extraction procedures for the determination of adenosine-5 -triphosphate in sediment samples by luciferin-luciferase assay. 

Fig. 8.1 Gas chromatogram of a saponified sediment sample extract Source Reproduced with permission from the American Chemical Society [8]... 

The sediment sample is allowed to dry in open air and then sieved. To 20g of the sample 20% distilled water is added for deactivation purposes and the excess water is then bound to active silica (Siloxid), so that a powdery consistency is obtained. The insecticides studied are extracted with petroleum ether (b.p. 30-60°C) in a Soxhlet apparatus. The extract is concentrated using the vacuum rotary evaporator and the coextractants are separated on a Celite oleum column. The petroleum ether eluate is then concentrated to a volume of 1ml and used for gas chromatography under the following conditions [10, 31-33],... 

Klenke et al. [5] described a technique for extraction of humic and fulvic acids from stream sediments and outlined methods for their determination. By means of flame atomic absorption spectrometry, the levels of environmentally important heavy metals (cadmium, copper, chromium, cobalt, nickel and lead) in the fulvic and humic acid extracts were compared with those in the original sediment samples. The pattern distribution of the respective metals in the two cases showed very close agreement, suggesting that the combined extract of humic and fulvic acids could be used as an indicator of the level of heavy metal pollution in flowing waters. 

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