Soil samples drying

In the method(s), petroleum constituents are extracted into a suitable solvent. Biogenic polar materials typically may be partially or completely removed with silica gel. The solvent is evaporated and the residue is weighed. This quantity is reported as a percentage of the total soil sample dry weight. These methods are better suited for heavy oil because they include an evaporation step. 

This example is based on an illustrative problem from Bolt et al. (53). Starting with a 100-g soil sample (dry weight) that is brought to water saturation, one finds a moisture content, W, of 60 cm3 of water per 100 g of dry soil. The concentration of the ions present in the soil solution at this moisture content is determined in a small amount of filtrate obtained from a subsample ... 

Evaporating dishes Labeling tape Top-loading balance Soil samples Drying oven Tongs... 

Particulate gravimetry is commonly encountered in the environmental analysis of water, air, and soil samples. The analysis for suspended solids in water samples, for example, is accomplished by filtering an appropriate volume of a well-mixed sample through a glass fiber filter and drying the filter to constant weight at 103-105 °C. 

A soil sample was taken from a field, transported back to the laboratory by road and stored for three weeks prior to analysis. The analytical procedure consisted of drying the soil in an oven at 100°C for 24 h before the analyte was extracted using 200 cm of dichloromethane. This extract was reduced in volume to 200 til and a 20 p.l aliquot then analysed by HPLC. A calibration was set up by measuring the response from a number of solutions containing known concentrations of the analyte. The resnlt obtained from the unknown , after suitable mathematical manipulation, indicated the original soil sample contained 20 0.05 mgkg of the analyte. Comment on the accuracy of this result. 

To enable comparison to this experimental approach, archaeological human bones of various ages and soil properties (Table 9.1) from the Anthropological Collection in Munich were analyzed. All German skeletal series come from humic soil with, neutral to slightly basic pH. The samples from Tinkey, Syria, coastal Pern and Egypt have been buried in dry, sandy soils. Soil samples from most of the excavation sites were available and bone sample... 

In the laboratory, soil samples collected in the held are mixed thoroughly and reduced in size to laboratory samples. The air-dried soils are passed through a 2-mm sieve in order to remove stones and roots, then the water content of the soil is calculated after drying at 105 °C for 5h. If the analytical samples cannot be analyzed immediately after drying and sieving, they should be stored at about —20 °C in glass or Teflon bottles fltted with screw-caps. 

Air-dried soil samples were screened through a 2-mm sieve, then the water content in the soil was calculated after holding the soil samples for 5h at 105 °C. 

Residual dinitroaniline herbicides are generally extracted from 10-25 g of air-dried soil samples using organic solvents such as ethyl acetate, acetonitrile, methylene chloride and acetone by sonication, mechanical shaking or Soxhlet extraction. If necessary, the extract is then cleaned by a Florisil column or SPE. The extract is allowed to evaporate completely to dryness and the residue is dissolved in an appropriate volume of the solvent for GC or HPLC analysis. 

For a soil sample, weigh 30 g (dry soil) of the sample into a 300-mL Erlenmeyer Aask and add 150 mL of water-acetoniAile (1 9, v/v). Sonicate the mixture for 30 min. Filter the exAact through a Alter paper overlaid with 20 g of Celite in a Buchner funnel into a 1-L round-bottom Aask with suction. Rinse the beaker and the Alter cake twice with 50 mL of acetoniAile. Combine the AlAates and concenAate to approximately... 

Weigh the samples [strawberry, rice grain, 25 g wheat grain, barley grain, 10 g rice straw, 5 g soil (dry weight basis), 30 g] in round-bottom flasks of appropriate volumes (500- or 300-mL). For soil samples add 40mL of IN sulfuric acid and 120mL of acetone to the flask, and for other samples add 20 mL of 1 N sulfuric acid and 60 mL... 

For wheat grain, extract the concentrate three times with 10 mL of chloroform-methanol (3 1, v/v). For the soil sample, extract the aqueous layer after washing with n-hexane twice with 60 mL of chloroform-methanol (3 1, v/v). Dry the chloroform-methanol layer with anhydrous sodium sulfate [for wheat grain, use a small amount (about 8 g) of anhydrous sodium sulfate] and collect the dried solution in a 200-mL round-bottom flask. Evaporate the solvent under reduced pressure and proceed to ion-exchange column chromatography. 

Transfer crop and soil samples from Section 6.1 (strawberry and rice grain) and Section 6.2 with 5 mL of methanol to 30-mL test-tubes and add to each test-tube 0.05 mL of concentrated sulfuric acid. Attach a condenser and reflux the solution at 75 °C for 60 min to esterify prohexadione to its corresponding methyl ester. Cool the reaction mixture to room temperature, add 20 mL of water and extract the reaction solution twice with 20 mL of dichloromethane. Dry the dichloromethane layer with a small amount of anhydrous sodium sulfate and collect the dried solution in a 100-mL round-bottom flask. Evaporate the solvent under reduced pressure. 

Transfer the concentrate from Section 6.1 to a 200-mL separatory funnel with 50 mL of water and add 10 mL of saturated aqueous sodium chloride solution. Extract twice with 100 mL of n-hexane. Dry the n-hexane extract by passing through about 80 g of anhydrous sodium sulfate on a glass funnel into a 500-mL separatory funnel for the rice samples and into a 500-mL round-bottom flask for the soil sample. Wash the anhydrous sodium sulfate with 30 mL of n-hexane and combine the washings into the vessel. The n-hexane extract of soil sample is evaporated to dryness under reduced pressure, then the soil residue is processed as described in Section 6.3.2. 

For soil samples, sufficient sample cleanup could be conducted even if the alumina column was changed to a Sep-Pak Alumina N cartridge (Waters) by the following process. The entire sample of the dried n-hexane extract (Section 6.2) is introduced into a Sep-Pak Alumina N cartridge, and the column is washed with 50 mL of n-hexane. Subsequently, pyriminobac-methyl is eluted with 3 mL of ethyl acetate, the solvent is evaporate to dryness under reduced pressure and the residue is dissolved in an appropriate volume of acetone for GC analysis. 

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. 

Weigh 50 g (dry weight) of soil sample into a 500-mL Erlenmeyer flask. Add 250 mL of acetone-water (4 1, v/v) and shake vigorously for 1 h and filter the solution by suction through Whatman No. 2 filter paper covered with a 1-cm layer of Hyfio Super-Cel. Rinse the flask and cake with 100 mL of acetone. Combine the filtrate and rinsings and concentrate to less than 40 mL below 40 °C with a rotary evaporator. 

Weigh 40 g (dry weight basis) of the soil sample into a 500-mL round-bottom flask and add 200 mL of acetone-water (3 1, v/v) mixture. Attach a condenser to the flask and perform reflux extraction at 80 °C for 1 h. Filter the extract through a Alter paper on a Buchner funnel with suction into a 500-mL round-bottom flask. Rinse the residue on the funnel with 130mL of acetone, and Alter in the same manner. Combine and concentrate the extract under reduced pressure to 50 mL. Transfer the concentrate into a 200-mL separatory funnel with 10 mL of saturated aqueous sodium chloride... 

Plant material should be added to a disk mill (grain or seed matrices) or a vertical batch processor (all other matrices). Add an equal portion of pelletized dry-ice to the sample (vertical processor only). Macerate the plant sample (or sample -I- dry-ice) until a homogeneous mixture is obtained. Soil samples should be well mixed or... 

Weigh 50 g (dry weight) of the soil sample into a 500-mL Erlenmeyer flask and extract with 150 mL of acetone by shaking for 30 min. Filter the extracts by suction through a Buchner funnel using Whatman 934-AH filter paper and collect the extracts in a 500-mL round-bottom flask. Concentrate the organic extracts at 40 °C under reduced pressure. 

For soil. Extract 50 g (dry weight, containing about 5 g of the water) of the soil sample similarly as described above, using 95 mL of the distilled water. 

A 50-g (based on the oven-dry weight) soil sample is weighed into a centrifuge tube and blended at 7000 rpm with 100 mL of methanol for 10 min. The resulting... 

Soil samples are handled by shaking 2 pounds of soil, the moisture content of which has been determined for subsequent correction to dry weight, with 1.5 ml. of benzene per gram of soil for 1 hour in the metal cans on the mechanical stripper. 

Soil Drying of soil sample followed by sieving digestion with HN03 centrifugation ICP/AES 0.09 pg/g 97-103 Schmitt et al. 1988... 

Soil Drying of sample, dry ashing, digestion with acid, and dilution with water AAS 2 pg/g 79-103 Beyer and Cromartie 1987... 

CIPAHs, PBDEs, and PCDD/Fs in soil samples were in ng/g dry weight. For PCDD/Fs in human samples, pg WHO-TEQ1998/g lipid (World Health... 

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