Sediments extraction/sediment procedure

Montgomery, E. M., and Senti, F. R. (1958). Separation of amylose from amylopectin of starch by an extraction-sedimentation procedure./. Polym. Sci. 28 1-9. 

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. 

Southwest Water Laboratory (1971) Method No. SP 8/71. Sediment Extraction Procedures, Athens, Georgia, USA. 

The supercritical fluid chromatographic procedure [20] described in section 9.1.1.5 for the determination of organochlorine insecticides in soils has also been applied to river sediments. Snyder et al. [20] compared supercritical fluid extraction with classical sonication and Soxhlet extraction for selected organochlorine insecticides. Samples of sediments extracted with supercritical carbon dioxide modified with 3% methanol at 350atm and 50°C gave =85% recovery of organochlorine insecticides including Dichlorvos, Diazinon, Endrin, Endrin aldehyde, decachlorobiphenyl, p,p -DDT and Mirex. 

Snyder et al. [253] compared supercritical fluid chromatography with classical sonication procedures and Soxhlet extraction for the determination of selected insecticides in soils and sediments. In this procedure the sample was extracted with carbon dioxide modified with 3% methanol at 350atm and 50°C. An excess of 85% recovery of organochlorine and organophosphorus insecticides was achieved. These included Dichlorvos, Diazinon, (diethyl-2-isopropyl-6-methyl 4-pyrimidinyl phosphorothioate), Ronnel (i.e. Fenchlorphos-0,0 dimethyl-0-2,4,5-trichlorophenyl phosphorothioate), Parathion ethyl, Methiadathion, Tetrachlorovinphos (trans-2-chloro-l-(2,4,5 trichlorophenyl) vinylchlorophenyl-O-methyl phenyl phosphoroamidothioate), Endrin, Endrin aldehyde, pp DDT, Mirex and decachlorobiphenyl. 

Japenga et al. [56] determined polychlorinated biphenyls and chlorinated insecticides in River Elbe estuary sediments by a procedure in which the sediments were pretreated with acetic acid, mixed with silica and Soxhlet-extracted with benzene/hexane. Humic material and elemental sulphur were removed by passing the extract through a chromatographic column containing basic alumina, on which sodium sulphite and sodium hydroxide were adsorbed. Silica fractionation was followed by gas chromatography to analyse chlorinated pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons. Recovery experiments with standard solutions gave recoveries of 90-102%. 

MIP are often generated as simple bulk polymers to be ground into fine particles, which are subsequently sieved and sedimented - admittedly a time-consuming process, which requires large amounts of solvents. The loss of fine polymer particles in the sedimentation procedure is also not negligible. The result usually is a polymer powder with particle sizes of a relative broad size distribution. After the template has been extracted, this material can be packed into LC-columns [17,29,30], CE-capillaries, or be used directly in the batch mode. 

The interlaboratory results obtained from the analysis of defined standard solutions, but also from the analysis of sediment extracts prepared either by the coordinator of the study or by the participants themselves, also provide a measure of the variation between laboratories. The results show that the interlaboratory reproducibility ranges from 6.5% for the defined dioxin sample to 27.9% for the sediment sample extracted by the participants themselves. As was mentioned before, the reproducibility for this last sample is relatively high and most presumably due to the introduction of extra handlings (extraction and cleanup) to the total procedure. In addition, the fact that not all the participants had prior experience with the extraction protocol to be used could have added to the increase in variability of the process. Furthermore, the dilution factor was not dictated. This also introduces a certain degree of variation. For the reproducibility of the DR CALUX bioassay itself and not caused by differences in operating extraction conditions, the maximum variation between laboratories was observed to be 18.0%. The results for the sediment extract samples can also be used to estimate the method variability for extracts, that is, based on samples of unknown composition. Again, given the intra-as well as the interlaboratory variations observed in this study, it appears justified to conclude that the standard deviation of the means provides a reasonable estimate of the method variability, based on the overall aver-... 

The in vitro bioassay for dioxins with cleaned sediment extracts (DR-CALUX) proved to comply with the QA/QC criteria needed to guarantee the reliability of data in an inter- and intralaboratory study (Besselink et al., 2004). The chemical stability of dioxins makes it possible to apply destructive clean-up procedures which remove all matrix factors. Sample extraction and cleanup for other in vitro bioassays for specific mechanisms of toxicity require further development to make sure that the chemicals of interest are not lost or unwanted chemicals included in the sediment extract to be tested. Table 4 summarizes possible bioassays that could be performed in addition to chemical analyses with the dredged sediment in a licensing system. 

The development of solvent-impregnated resins and extraction-chromatographic procedures has enabled the automation of radiochemical separations for analytical radionuclide determinations. These separations provide preconcentration from simple matrices like groundwater and separation from complex matrixes such as dissolved sediments, dissolved spent fuel, or nuclear-waste materials. Most of the published work has been carried out using fluidic systems to couple column-based separations to on-line detection, but robotic methods also appear to be very promising. Many approaches to fluidic automation have been used, from individual FI and SI systems to commercial FI sample-introduction systems for atomic spectroscopies. 

Maher [6] has described a method for the determination of down to O.Olmg/kg of organoarsenic compounds in marine sediments. In this procedure, the organoarsenic compounds are separated from an extract of the sediment by ion exchange chromatography, and the isolated organoarsenic compounds are reduced to arsines with sodium borohydride and collected in a cold trap. Controlled evaporation of the arsine fractions and detection by atomic absorption spectrometry completes the analysis. 

Just choosing the most widely applied procedure (namely that of Tessier et al., 1979) could yield data of doubtful reliability for a particular matrix or objective, but may nevertheless allow comparison with results of many other studies. In practice, there is always an optimisation necessary between compatibility and reliability. The limitations reported here and elsewhere lead to the conclusion that results given by sequential sediment extraction experiments can be used for an assessment of specific release scenarios particularly related to changing pH, complexing ligand availability and redox environments rather than for true metal speciation in sediments. The latter can be achieved only by using intrumental speciation techniques, either alone or in combination with sequential extraction. It is in this area of research that new developments have appeared since the first edition of this volume. Particularly... 

Campbell, M., G. Bitton, B. Koopman, and J.J. Delfino. 1992. Preliminary comparison of sediment extraction procedures and exchange solvents for hydrophobic compounds based on inhibition of bioluminescence. Environ. Toxicol. Water Qual. 7 329-338. 

For many samples, pre-concentration is essential, and this is commonly achieved by solvent extraction. Often the nickel tetramethylenedithiocarbamate complex is extracted at pH 2-4 into 4-methylpentan-2-one.1 This system has been applied to soil and sediment extracts39 and to water samples.40-42 Kinrade and Van Loon43 used a mixture of ammonium tetramethylenedithiocarbamate and diethylammonium diethyldithiocarbamate to extract a range of elements, including nickel, into 4-methylpentan-2-one from water samples adjusted to pH 5. New solvent extraction-based procedures are still being published regularly for environmental samples such as plant tissues and water samples.44... 

Several chemical reactions, including calcium carbonate and hydroxyapatite precipitation, have been studied to determine their relationship to observed water column and sediment phosphorus contents in hard water regions of New York State. Three separate techniques have been used to Identify reactions important in the distribution of phosphorus between the water column and sediments 1) sediment sample analysis employing a variety of selective extraction procedures 2) chemical equilibrium calculations to determine ion activity products for mineral phases involved in phosphorus transport and 3) seeded calcium carbonate crystallization measurements in the presence and absence of phosphate ion. 

Few papers on the analysis of PCAs or their measurement in environmental samples have reported on techniques to minimize contamination. PCAs (C10-C13,60-70% Cl) levels ranging from 4 ng g 1 to 25 ngg 1 in sodium sulfate were found in procedural blanks used in sediment extractions [28]. PCAs (C10-C13,60-70% Cl) were also detected in DCM (0.15 pg 1 ) left to evaporate in an open flask overnight it was unclear, however, whether contamination was a result of airborne PCAs or was from the DCM itself [28]. Similar problems have been encountered with airborne PCB contamination of analytical labs [65]. Significant procedural blanks result in higher method detection limits, i. e., the mean plus three times the standard deviation in the background signals from procedural blanks (sodium sulfate) [14,66,67]. 

Extraction system such as that offered by Dionex Corp. Some laboratories analyze alkenones as part of the total lipid extract others prefer to run cleaner fractions following one of a number of schemes of fraction purification using silica gel columns or thin-layer chromatography (Villanueva et al., 1997). Most open-ocean sediment extracts do not contain appreciable amounts of interfering lipids however, some samples with more complex matrices may benefit from cleanup procedures. 

In the investigation of organic compounds in sediments the experimental procedures invariably include a separation scheme to divide and simplify total sediment extracts into suitable fractions of different polarity. Typically, this experimental procedure will yield a number of fractions containing principally hydrocarbon, ketone, carboxylic alcohol or polar components. The reconstituted ion (RIC) from gc-ms analysis of three such discussed herein to illustrate the observed of marker compounds in marine sediments and inferred biological origins. 

Arsenic speciation by 1C can be simple and reproducible. One procedure, conductivity detection of As(III) and As(V), was reported by McCrory-Joy [17]. The procedure was sensitive and there was no interference by ions such as NO,c. HP04, and S04 , that are present in the sediment extract. However, detection of As(IIl) is not possible by suppressed conductivity because of its weak acid strength. 

Considering all observations presented, a distinct difference is evident in the distribution of abundances of the bound DDT-related compounds as compared to the substances within the extractable fraction. The main metabolite of the anaerobic degradation pathway (DDD), most abundant in the sediment extracts, had no relevance in the degradation products of all procedures applied. 

Approaches for the Extraction, Cleanup Procedures and Analysis for Soil, Sediment and Sewage Sludge... 

Exchangeability of sediment-bound radiocesium. The exchangeability of sediment-bound radiocesium has been investigated by extracting sediments with 0.1 M NH4-acetate (9), These extractions have been performed on all sediments shown in Figure 1. Sediment samples from different depths were extracted three times sequentially, each step for 24 hours, with 0.1 M Nlij-acetate at a liquid/solid ratio of 10 L/kg. Further details on the extraction procedure and radiocesium measurements are given in f9j. 

It is emphasized that, owing to the inherent selectivity of (LE)SS, sample cleanup procedures can often be minimized. An important example is the analysis in a crude river sediment extract of ul-tralow traces of dibenzo[d ,/]pyrene, the most carcinogenic PAH known to man. Another interesting application is the identification and quantification of PAH metabolites in samples for biological monitoring. Although SS is not appropriate for highly polar compounds it can be applied to monohydroxy PAHs. 

Preparation of soil—sediment of water samples for herbicide analysis generally has consisted of solvent extraction of the sample, followed by cleanup of the extract through Uquid—Uquid or column chromatography, and finally, concentration through evaporation (285). This complex but necessary series of procedures is time-consuming and is responsible for the high cost of herbicide analyses. The advent of soUd-phase extraction techniques in which the sample is simultaneously cleaned up and concentrated has condensed these steps and thus gready simplified sample preparation (286). 

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