Shakers, soil extraction

A 20-g sample of air-dried soil is extracted with 100 mL of ethyl acetate in a flask shaker for 45 min. After shaking, the extract is decanted and separated. The soil is re-extracted with 100 mL of ethyl acetate for 45 min. The combined soil extracts are filtered through a Whatman No 1 filter paper and the filter cake is washed with an additional 20 mL of ethyl acetate. The extracts are evaporated nearly to dryness, under vacuum, using a rotary evaporator. The residue is dissolved in an appropriate volume before GC analysis. ... 

A commonly used extraction technique involves shaking soil with a suitable solvent on a mechanical shaker at about 300 rpm. After extraction, the soil extracts are collected by centrifugation followed by decantation or filtration. This technique could be used for any amount of soil samples (from 10 to >100g). Soil samples greater than 100 g require efficient agitation to achieve acceptable recoveries. 

Cotterill [119] used the soil extraction method devised by McKone [120] in which a 25g sample of soil was extracted with 50ml of methanol by shaking on a wrist-action shaker for lh. The resulting soil slurry was filtered through a Whatman No. 42 filter-paper. For gas chromatography, a 2ml... 

The Olsen method is extremely sensitive to changes in operating conditions, and unless care is taken, reproducible results will not be obtained. It is therefore imperative that all the extractions are done at the same temperature, at the same shaking speeds, and on the same shaker each time if results are to be compared between soils. For example, it is important even to adopt a standard method of filtration. The one we use is to swirl the flask briskly, add soil extract to the filter paper, and then replace the flask on the bench. Proceed in exactly the same way with the next soil replicate. If a top up is required, all flasks should be topped up in the same way. Analyze the same day if possible, although extracts may be frozen. 

The analytical method for difiufenican is as follows. A 50-g soil sample is extracted with 100 mL of acetonitrile for 45 min with a rotary shaker at 240 rpm. The mixture is centrifuged for 10 min at 3000 rpm, the supernatant is filtered through a glass filter funnel with anhydrous sodium sulfate and the filtrate is collected. ... 

Soil samples are extracted with buffered acetonitrile with a mechanical shaker. Alter centrifuging, aliquots of the extracts are amended with isotopically labeled internal standards and evaporated to dryness. The samples are reconstituted and analyzed by LC/MS/MS. This method determines soil residues of flucarbazone-sodium, sulfonic acid, sulfonamide and NODT with an LOQ of 0.001 mg kg for each analyte. 

Organic solvent extraction. Two analytical methods for acetamiprid have been developed One method is for the parent only and the other determines the total residue of the parent and its metabolites (lM-1-2, lM-1-4 and lC-0). Air-dried soil (20-g equivalent dry soil) is weighed into a centrifuge tube and imidacloprid residue is extracted with 100 mL of methanol-0.1M ammonium chloride (4 1, v/v) using a mechanical shaker for about 30 min. After shaking, the tube is centrifuged at 8000 rpm for 2 min. The supernatant is filtered and the analysis of the soil residue is carried out in the same manner as described above for the parent compound. 

For soil samples, shake 20 g of a prepared air-dried soil sample with methanol-1 N hydrochloric acid [50 mL, 3 1 (v/v)] on a mechanical shaker for 30 min. Centrifuge the sample at 3500 rpm for 5 min and decant the supernatant into a round bottom flask (250-mL). Add a second 50 mL of methanol-1 N hydrochloric acid (3 1, v/v) to the soil sample and shake the mixture on a mechanical shaker for another 30 min. Centrifuge the sample at 3500 rpm for 5 min and then decant the supernatant into the same round-bottom flask (250-mL), combining the extracts. 

Recovery of acetamiprid, IM-1-2 and IM-1-4. Combine 20 g of the air-dried soil with 100 mL of a mixed solvent of methanol and 0.1 M ammonium chloride (4 1, v/v) in a 250-mL stainless-steel centrifuge tube, shake the mixture with a mechanical shaker for 30 min and centrifuge at 8000 r.p.m. for 2 min. Filter the supernatant through a Celite layer (1-cm thick) under reduced pressure into a 500-mL flask. Add a second 100 mL of mixed solvent to the residue and then extract and filter in the same manner. Combine the filtrates and add 150mL of distilled water with 1 g of sodium chloride. Transfer the aqueous methanol solution into a 1-L separatory funnel and shake the solution with 200 mL of dichloromethane for 5 min. Collect the dichloromethane in a flask and adjust the pH of aqueous methanol to 13 with sodium hydroxide. Extract the solution with two portions of 200 mL of dichloromethane for 5 min. Combine the dichloromethane extracts and pass through a filter paper with anhydrous sodium sulfate. Add 0.5 mL of diethylene glycol and then concentrate the dichloromethane extract to about 0.5 mL on a water-bath at ca 40 °C by rotary evaporation. 

Combine 50 g of the air-dried soil with 100 mL of acetone and shake the mixture with a mechanical shaker for 15 min. Filter the mixture through a fluted filter paper into a 500-mL flask. Wash the residue on the filter with 50 mL of acetone. Combine the filtrates and remove acetone by rotary evaporation. Transfer the residue with 150 mL of a potassium chloride solution into a separatory funnel, extract the solution with two portions of 50 mL of dichloromethane and collect the organic extracts in a flask. Filter the combined solvent extracts, together with the washings of the collecting flask, through anhydrous sodium sulfate into a 300-mL flask. Remove dichloromethane by rotary evaporation. Dissolve the residue in 10 mL of carbon tetrachloride. 

Alford Stevens et al. [49] carried out a multi-laboratory study of automated gas chromatography-mass spectrometric determinations of polychlorinated biphenyls in soil. The influence of various factors on the accuracy of analytical results were studied. Shaker extraction for 12.5h followed by Florisil chromatography were demonstrated to be the most reliable methods for extraction and clean-up. 

Weigh 5.00 g of each soil sample to be tested into dry 50-mL Erlenmeyer flasks. Pipet 20 mL of extracting solution into each flask. Stopper and shake on a shaker for at least 20 min. 

For the four herbicides, the soil fraction in the sample bottle was extracted by adding 50 mL of diethyl ether followed by agitation for 15 minutes on a wrist-action shaker. The diethyl ether was decanted and the high concentration samples were extracted three more times with 50 mL of diethyl ether by hand shaking the capped bottles for 2 to 3 minutes. The low concentration samples were extracted two additional times with 25 mL of diethyl ether. 

For the two insecticides, the soil was extracted with 75, 50 and 50 mL of an acetone benzene methanol (1 2 1 by vol.) mixture. The sample bottles were capped and agitated for 60 minutes on a wrist-action shaker for each extraction. The contents of the bot-... 

Procedure (extraction). Transfer 5 ml (scoop filled and struck off level without tapping) of air-dry soil, sieved to 2 mm into a bottle (e.g. wide-mouth, square HDPE). Add 100 ml of sodium bicarbonate reagent, pH 8.50, cap the bottle and shake on a reciprocating shaker, at approximately 275 strokes of 25 mm length per minute, for 30 min at 20°C. Filter a portion immediately through a Whatman No. 2 filter paper, rejecting the first few millilitres of filtrate. Carry out a blank determination. 

Procedure (extraction). Weigh 10 g air-dry soil sieved to s2 mm (10 mesh) into a 50-ml conical flask. Add 25 ml of calcium phosphate extractant (50 ml for peat or compost) and shake on a reciprocating shaker (at approximately 200-275 oscillations of 25 mm per minute) for 30 min. If the presence of sol-... 

Procedure (extraction). Transfer 2.5 g air-dry soil, 2 mm mesh size, into a 250 ml polypropylene screw-cap centrifuge bottle/tube and add 100 ml acetic acid - 8-hydroxyquinoline reagent. Cap the tube and shake overnight (17 h) on a reciprocating shaker, at approximately 275 strokes of 25 mm length per minute at a constant temperature (20°C). Centrifuge for 15 min at 2800 rpm and remove an aliquot for the determination of acid extractable inorganic phosphorus (a). 

Shaking. Pollutants are generally extracted from water samples, and in some cases soil samples, by shaking with an appropriate solvent or solvent combination. Mechanical shakers are used to handle several water or soil samples at once. These devices allow the analyst to conduct long-term extractions (e.g., 24 h) if required. Two or more shakings normally are required for complete removal (i.e., >98%) of the toxicant from the sample matrix. 

The bottles are removed from the shaker, and the soil suspensions are filtered through Whatman No. 1 filter papers. They may be analyzed immediately or stored at -18°C until required. On thawing, there is usually a white precipitate of calcium sulfate (CaS04) in the extracts. The bottles should be shaken thoroughly and then allowed to stand so that the precipitate settles out again before any extract is removed for analysis. The extracts are then refrozen in case repeat analyses are required. 

Extraction of Soils. The soil samples were pulverized, thoroughly mixed, and their moisture contents were determined. They were extracted by shaking in a mechanical shaker for 1 hour with isopropyl alcohol, 1 ml. per gram, and redistilled hexane, 1 ml. per gram. The extract was recovered by decantation, washed free of alcohol, and dried with anhydrous sodium sulfate. This extract was used without cleanup for thin layer or gas chromatography. To check on the extraction procedure, some samples were re-extracted. with isopropyl alcohol-hexane mixture or with acetone. These additional extracts did not contain significant amounts of the pesticides. 

The experiments were performed by using a batch shaker technique to investigate the extraction removal efficiency of lead from ccxitamina soil The procedures followed in this study are summarized below. 

In the frame of the interlaboratory study on single extraction for soil analysis, an example has demonstrated that it is not sufficient to use a standard protocol to achieve comparability of data, i.e. it is also necessary to strictly comply with the technical requirements of the scheme one laboratory used a reciprocating shaker instead of the recommended end-over-end shaker and obtained systematically low results the repetition of the analyses clearly showed that the error was due to this fact (Table 12.3). This... 

RESULTS OF AN INTERLABORATORY TESTING OF A SINGLE EXTRACTION PROCEDURE APPLIED TO A SEWAGE SLUDGE AMENDED SOIL (IN mg kg" ) OBTAINED USING A RECIPROCATING AND END-OVER-END SHAKER, RESPECTIVELY... 

To the fully grown culture of Aspergillus niger (obtained from soil using dilution plate method), taken in different conical flasks, 150 mg of each of the compounds were added separately and incubated on rotary shaker for a period of 72 hours at room temperatoe. Control was also maintained under the same conditions. At the end of the period, fungal medium was filtered and the mycelium discarded. The filtrate was extracted with chloroform, diethyl ether and ethyl acetate, in the same order. The extracts were dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure conditions to yield a pasty mass for each of the substrates. 

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