Digestion technique

Johnson SG, Fearey BL (1993) Spectroscopic study of thorium using continuous-wave resonance ionization mass-spectrometry with rrltraviolet ionization. Spectrochim Acta Part B 48 1065-1077 Knoll GF (1989) Radiation Detection and Measurement. J. Wiley and Sons, New York Kuss HM (1992) Applications of microwave digestion technique for elemental analyses. Fresenins J Anal Chem 343 788-793... 

A 68 element ICP-MS scan was performed on one dried white-colored paint sample. The chemical elements scanned for during the ICP analysis and the detection limits are provided in Table 5. Approximately 0.5 g of each sample was prepared by an acid digestion technique prior to conducting the ICP-MS analysis. Shown in Table 6 are the quantified ICP-MS results for the sample. Elements scanned for but not detected are either not present in the sample or may be present below the detection limit. 

Mahan K.I., Foderaro T.A., Garza T.L., Martinez R.M., Maroney G.A., Trivisonne M.R., Willging E.M. Microwave digestion techniques in the sequential extraction of cadmium, iron, chromium, manganese, lead and zinc in sediments. Anal Chem 1987 59 938-945. 

Enhancement of the solvent recovery of various sorbed hydrophobic organics by a digestion technique, which degraded the DHS. Simple adsorption onto the nonpolar region of humic molecules by van der Waals forces and hydro-phobic interfacial tension would probably hinder solvent recovery of adsorbed hydrophobic organics. 

The subsamples were split and sent to different laboratories to be subjected to ten commonly-used and proprietary leach/digestion techniques (a) aqua regia partial digestion method at Acme Analytical Laboratories (b) sodium pyrophosphate and cold hydroxylamine leaches at ALS Chemex (c) enzyme and TerraSol leach methods at Skyline Labs (d) Bioleach and soil gas hydrocarbon analyses at Activation Laboratories (e) Mobile metal ion (MMI) extraction at SGS Minerals (f) 4-acid near-total and sodium peroxide sinter total digestions (under the uses contract) at SGS Minerals and (g) de-ionized water leach at the USGS laboratories. 

The advantages of this digestion technique are the large number of samples that can be processed at one time, the simple and cheap glassware involved, and the fact that the digest may be used for the subsequent determination of not only nitrogen, but calcium, magnesium, potassium, sodium, phosphorus and iron. 

A convenient procedure for assessing the digestibility of forages is the cellulase digestibility technique. This was refined by Jones and Hayward (1973) at the Welsh Plant Breeding Station (WPBS) in Aberystwyth (since 1992, the Institute for Grassland and Environmental Research). It was later extended to a two-stage procedure with a pepsin pre-treatment (Jones and Hayward, 1975). 

Jones, D.I.H. and Hayward, M.V. (1973) A cellulase digestion technique for predicting the dry matter digestibility of forages. Journal of the Science of Food and Agriculture 24, 1419-1426. 

Analysis of major elements (except Si) and total phosphorus on bomb-digested samples was accomplished by inductively coupled plasma emission spectrometry (ICP, ARL model 34,000). Silicon was analyzed colorimetrically (14). Phosphorus in total digests was also determined colorimetrically by the method of Murphy and Riley (15), as modified by Erickson (16). To avoid interference from fluoride ion used in the digestion technique, sample volumes were restricted to <1.5 mL in the standard P analytical protocol. 

A comparison of currently utilized mechanical and digestion techniques is shown in Table 2.2. Each technique has both advantages and limitations, and some may be used in combination for optimum extraction. 

Digestion Techniques For nonvascularized or low-water-content tissues such as bone, cartilage, or hair, a mechanical technique may do little to disrupt cellular structure and extract analytes. Extreme measures such as digestion with strong acid (i.e., 12 N HC1) are routinely used for DNA or nucleic acids, which can tolerate the harsh conditions. Alternatively, certain enzymes can be used to digest tissue samples. Commercial devices are available which contain digestion bombs fabricated from material resistant to corrosive media. 

The advent of FAB mass spectrometry has allowed the routine molecular weight determination of polar molecules, without derivatization, up to ca 3,000 Daltons, and in exceptional cases, within 1 mass unit to the region of 8,000 Daltons. This advance, coupled with FAB fragmentation, and enzymic digestion techniques, has allowed the rapid solution of a number of problems in protein and peptide chemistry - problems which were hitherto rather difficult to solve. Examples are given. 

An appreciable amount of work has been carried out on the application of microwave digestion techniques to the determination of heavy metals, arsenic and uranium in soils. 

Routinely, common chemical and enzymatic techniques are used to obtain protein fragments. Unfortunately, when enzymatic digestion techniques and nanograms quantities of proteins are used, the method become ineffective due to dilution and reduced enzymatic activity. An alternative approach to overcome this problem is the use of proteolytic enzymes immobilized to a solid support and a small-bore reactor column. Using trypsin immobilized to agarose, tryptic digests of less than 100 ng of protein can be reproducible obtained (49). 

This laboratory experiment describes the preparation of a vegetation sample (e.g., grass) for radiochemical analysis. The sample is dried and ashed. In Part 12A, the ash is fused with sodium hydroxide and sodium carbonate to bring it into solution. An alternative method in Part 12B uses a microwave-assisted digestion technique with nitric and hydrofluoric acid. The prepared sample is suitable for radionuclide analysis, notably for radio-strontium or plutonium. 

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