Sampling soil samples used

Grain size distributions for sediments and soils are used to determine the amount of sand, silt, and clay present in a sample. For example, a grain size of 2 mm serves as a boundary between gravel and sand. Grain size boundaries for sand-silt and silt-clay are given as 1/16 mm and 1/256 mm, respectively. 

There is a direct and an indirect method of measuring specific soil resistivity. The direct method is carried out in the laboratoiy on a soil sample using a soil box as shown in Fig. 3-16. The resistivity of a soil specimen of cross-section, S, and length, I, is measured and the specific resistivity determined ... 

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. 

Linderholm, J. and E. Lundberg (1994), Chemical characterization of various archaeological soil samples using main and trace elements determined by inductively coupled plasma atomic emission spectrometry,. Archaeol. Sci. 21, 303-314. 

The HS samples used in this work were obtained from the Standard and Reference Collection of HAs and FAs of the International Humic Substances Society (IHSS), with the exception of the HA from an alluvial soil. The origin and nature of HS, with the corresponding codes, abbreviations and concentrations used, are shown in Table 1. 

Soil, sediment, citrus leaves, coal, coal fly ash Clean up sample using disposable Florisil cartridge elute with methylene chloride in hexane and hexane/acetone GC/ECD NR 80-104 Lopez-Avila et al. 1989... 

A comparative study was made between determinations of the 15N content of plant and soil samples, using the methods of the International Atomic Energy Agency Laboratories, based on MS, a novel automatic N analyzer coupled to a mass spectrometer and a microprocessor-controlled emission spectrometer. Although the latter instrument is fast, its precision may be insufficient to determine 15N in soil59. 

Two samples from the soil profile were randomly separated into very small subsamples (a few millimetres across) and analysed after aqua regia digestion to assess the heterogeneous nature of the Au distribution. Replicate sub-samples were analysed to assess the likelihood of finding Au in other soil particles using LA-... 

In the nineteen-seventies, new methods for pattern recognition have been developed by means of quantitative analogy models. The analogy analysis implies looking for regularities in the observations made. The individual items that are analyzed are called objects. The objects are alike that will be brought into the same class. In our case the number of classes would be two, the two barley cultivars (Etu,Tellus). The samples obtained from soil are used as test objects. 

If the soil contains significant amounts of nitrate, which should be included with the organic and ammonium-N for total nitrogen, it must be reduced to ammonium-N by the following procedure (Method 5.6a.i). Determination of N on duplicates of the same soil sample with and without a reducing step will enable an estimation of the nitrate-N (plus any nitrite-N) by difference. A more precise colorimetric determination of just the nitrate component uses the method described for herbage, except that 10 ml of fresh or freshly thawed soil is used. 

The standard diluent and the sampler wash solution must have the same matrix as the samples. Therefore, if analysing soil samples use the soil extraction solution (0.01 M CaCI standards and as sampler wash solution. 

Encapsulation of herbicides within anionic clays was readily identified by the loss of HRMAS NMR signal associated with immobilization of the molecules between clay layers.103 The application of HRMAS to soil samples has been shown to provide important results on the interaction of herbicide and other organic components with the soil matrix, using ID lH HRMAS, selective TOCSY and 2D TOCSY experiments.104 Significant advantages to the HRMAS approach are its reduced samples preparation needs, with no extraction, pre-treatment or purification required. 

In 1994, Dadfarnia and McLeod described the analysis of uranium in surface waters and sea water using a simple FI system with an alumina column for preconcentration.77 Species eluted from this column were delivered to an ICP-MS as the detector. Also in 1994, Hollenbach et al. described the automation of extraction chromatographic methods based on TRU-Resin and TEVA-Resin to separate and preconcentrate U, Th, and Tc from soil samples, using ICP-MS for detection.49125 In 1996, Aldstadt et al. described the use of FI and extraction chromatography using TRU-Resin to determine U in environmental samples by ICP-MS.78... 

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