Grass, sampling

At the present, we are unaware of NMR data in the literature on humin of aerobic soils although such data have been presented for whole soils (Wilson et al., 1981b) and for histosols (Preston and Ripmeester, 1982). We recently collected samples of an aerobic soil from southern Georgia. The sandy soil was essentially forming in a fallow agricultural field and the primary contributors to the soil were various grasses. Samples were collected from the upper 5 cm and from 5-10 cm and were later extracted to isolate humic acids and humin. 

Wheat straw Triticum Native lignins of grass samples 92 43 5 5/49/46... 

Dimers 39 and 40, issued from grass samples, reveal the linkage type of p-cou-maric and ferulic esters and show that some ester bonds survive thioacidolysis. Dimer 39 confirms thatp-coumaric acid is ester-linked at Cy of S lignin units [60,61]. Compound 40, tentatively assigned from its mass spectral fragmentation pattern, may originate from ferulic units ester-linked to pentose units [85]. 

As a consequence, accumulation of Pd and other PGE has been detected in road dust as well as soil and grass samples collected along highways (Barefoot 1999 Zereini and Alt 2000 Ravindra et al. 2004). Pd concentrations in airbome particulate matter (APM) samples (particulate matter <10 xm, PMIO) were reported to be in the range of 2.6-32 pg m on urban sampling sites (Gomez et al. 2003 Kanitsar et al. 2003 Zereini et al. 2005). 

TSP-LC-MS was appHed for determination and identification of the insecticide imidacloprid which was present as residue in vegetables at 0.01-0.60 mg 1 concentrations [288]. TSP-LC-MS was used to confirm positive LC-UV results (>0.05 ppm) of the insecticide hydramethylnon from extracts of pasture grass samples [289]. 

Grass samples, gramineae or poaceae or other species such as fescue, alfalfa, etc., are usually collected from an area of 20 x 20 = 400 m in the outside environment, appropriately fenced to prevent interference by animals and therefore undisturbed. Each sample is cut from an area of about 3 m (0.125 kg of grass per m ) and then the radioactivity is measured by gamma-spectrometry. 

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