Sampling and homogenization

Stability is a critical variable that must be considered as part of method development. When considering stability within the method, reviewing the available stability data for the analyte is very helpful. Information on the stability of the analyte in aqueous 

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Theories of Heterogeneity, Sampling and Homogenizing. Elsevier Amsterdam, 1992. 

Gy PM (1992) Sampling of heterogeneous and dynamic material systems - theories of heterogeneity, sampling and homogenizing. Elsevier, Amsterdam... 

Gy, PM. (Ed.) Sampling of Heterogeneous and Dynamic Material Systems. Theories of Heterogeneity, Sampling and Homogenizing Data Handling in Science and Technology, Elsevier, Amsterdam, 1992... 

Having described all of the materials, selected the samples and homogenized them, the next step in the analysis is to identify the chemical constituents. This is achieved by using presumptive tests, TLC and a confirmatory technique. 

Whole fish Freeze fish sample and homogenize add MeOH and extract ultrasonically purge-and-trap on adsorbent GC/MS equipped with fused silica capillary column 7.5x10 MS/S 6.2% RSD Dreisch and Munson 1983... 

The water material for trace element analysis was then acidified to pH 2 (if not acidified at the sampling) and homogenization was accomplished with a PTFE paddle. 

Reduce particle size of gross i sample and homogenize I ... 

In any method involving powders, accurate sampling and homogeneous mixing can present problems. They are not trivial, and errors in these operations can produce large errors in the final result. Such matters are discussed by Klug and Alexander [G.39] and Grant and Pelton [14.16]. 

Add 100 ml of n-hexane to the unfiltered water sample in one or more wide-necked bottles with conical shoulders, as appropriate to the quantity of sample, and homogenize for 15 minutes as above. Allow to stand for 2 hours, by which time the phases are separated to the extent that the solvent can be siphoned off and transferred to a 1000-ml separating funnel. Return any aqueous phase in the separating funnel to the widenecked bottle. Transfer the n-hexane phase through the neck of the separating funnel into a 300-ml tapered flask through a glass funnel with... 

Procedure. Pipette 100 ml. of 3 per cent meta-phosphoiic acid into a Waring Blendor and remove the oxygen. Add 20 g of the sample and homogenize for 1-2 min in a carbwi dioxide atmosphere. Deoxygenate 6 ml. of a 1 M acetate pH 4-7 buffer in a Kalousek vessel and add 4 ml. of the liquid homogenate. Finally record the anodic wave of ascorbic acid. 

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