Precision gradient analysis

We can measure a polymer s density by one of two methods density gradient column analysis and densimetry. Each of these methods can measure the density of a sample to a precision of four significant figures. 

The transport equation (441) has been studied in another context j30.35.36 it is out of place to give this analysis here and we shall merely quote the conclusion in the case of small gradients, Eq. (440) is entirely equivalent to the well-known Stokes-Navier equation of hydrodynamics.f More precisely, the average velocity w, which from Eqs. (424), (426), and (439) is given by ... 

HP-jS-CD were added. All compounds were resolved in 20 min (see Figure 5). The data indicated that the validated method offered equivalent and complementary information, in terms of selectivity, sensitivity, accuracy, linearity, and precision, to that of an established gradient LC method employed for similar purposes. Ragaglitazar is a dual peroxisome proliferator-activated receptor ot and y agonist intended to restore insulin sensitivity and correct diabetic dyslipidemia. A chiral CZE method combining two CDs, sulfobutylether-jS-CD and dimethyl-/i-CD, lent itself to the analysis of ragaglitazar, its distomer (the (+)... 

BLS). This paper describes a novel and alternative method for performing DCP analyses and in particular a new procedure for the formation of the spin fluid density gradient external to the DCP disc. This new patented method ( 3), known as the External Gradient Method (EGM), will be compared to the BLS method of analysis. The quantitative precision of the results obtained with EGM and BLS will be compared by statistical analysis.In addition, qualitative advantages of the EGM over the BLS method will be given. 

We have employed two multi-elemental techniques (INAA and ICP-AES) to determine sulphur, halogens and 14 other trace elements in urban summer rainfall. Quality control was assured using NBS reference materials. The overall accuracy and precision of these two methods makes possible the routine analysis of many environmentally important trace elements in acid rain related investigations. Enrichment factor calculations showed that several elements including S, Cu, Zn and Cr were abnormally enriched in the urban atmosphere. A comparison of three separate sites showed a strong gradient of metal deposition from the industrial to the outlaying areas. 

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