Reference materials for small-sample analysis

1998 ◽  
Vol 360 (3-4) ◽  
pp. 376-379 ◽  
Author(s):  
R. Zeisler
Keyword(s):  
Reference Materials ◽  
Small Sample ◽  
Sample Analysis

Small sample analysis of a platform vibration via bootstrap method

2010 ◽  
Author(s):  
Zhongyu Wang ◽  
Jianyong Sun ◽  
Jianjun Zhang ◽  
Xintao Xia
Keyword(s):  
Bootstrap Method ◽  
Small Sample ◽  
Sample Analysis

THE ASSAY OF CORTICOTROPHIN IN MICE

1963 ◽  
Vol 44 (2) ◽  
pp. 237-249 ◽  
Author(s):  
Claus Rerup ◽  
Pavo Hedner
Keyword(s):  
Subcutaneous Administration ◽  
Small Sample ◽  
Lower Body ◽  
Sample Analysis ◽  
Lower Body Weight ◽  
Increased Sensitivity ◽  
The Mean ◽  
The Difference ◽  
Response Line ◽  
Free Plasma

ABSTRACT The assay of corticotrophin was performed in mice by means of small sample analysis of free plasma corticosteroids. In this method hypophysectomy was replaced by dexamethasone pretreatment. The response was measured preferably in a single mouse weighing 20 g or more. When mice of a lower body weight were used the plasma of two randomly assigned mice was pooled. Corticosteroids (mainly corticosterone) were determined fluorometrically in 0.25 (0.20) ml samples of plasma from heparinized blood. The results show that valid corticotrophin assays can be performed in mice both by the intravenous and subcutaneous route. Compared with the adrenal ascorbic acid depletion method or the plasma corticosteroid method in the rat the assay in mice was found to be at least five times more sensitive. 40 micro-units of corticotrophin were consistently detectable. Precision was dependent on the route of administration, the mean index of precision (s/b) being 0.20 in the intravenous and 0.12 in the subcutaneous assay. The difference was due to a steeper slope of the logdose-response line after subcutaneous administration. Contrary to the findings in the rat, corticotrophin A (oxycel purified) did not differ significantly in potency estimates from subcutaneous and intravenous assays in mice, when crude corticotrophin (U. S. P. Corticotropin Reference Standard) was the basis of comparison. Accordingly results of subcutaneous assays of corticotrophin A samples in terms of the U. S. P. standard were lower in mice than in rats. The use of gelatine instead of saline as diluent in the subcutaneous assays yielded slightly but not significantly higher potency estimates (25 per cent). The interpretation of the results is that for intravenous corticotrophin assays the mouse method is comparable to the rat assay. For subcutaneous corticotrophin assays, however, the mouse method is not suitable, if crude corticotrophin (U. S. P. standard) is the basis of comparison, but if corticotrophin A (oxycel purified) is the standard of reference (e. g. the Third International Standard for Corticotrophin), the mouse method may justifiably be used. The advantages of the mouse method are increased sensitivity, precision, convenience, and economy.

Aspects of Applied Statistics Underemphasized in Electrical Metrology

1978 ◽  
Vol 15 (3) ◽  
pp. 197-201
Author(s):  
K. R. Spriggs
Keyword(s):  
Curve Fitting ◽  
Small Sample ◽  
Applied Statistics ◽  
Academic Emphasis ◽  
Sample Analysis ◽  
Specification Error ◽  
Measurement Analysis ◽  
Practical Measurement

The academic emphasis given to aspects of statistics in electrical metrology is questioned. It is proposed that textbook, and consequently lecture course treatment of statistics falls short in equipping the engineer for practical measurement analysis. Curriculum modifications are suggested whereby practical error specification, error combination techniques, small sample analysis and curve fitting are adopted as objectives.

scholarly journals Blank Assessment for Ultra-Small Radiocarbon Samples: Chemical Extraction and Separation Versus AMS

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1322-1335 ◽  
Author(s):  
Guaciara M Santos ◽  
John R Southon ◽  
Nicholas J Drenzek ◽  
Lori A Ziolkowski ◽  
Ellen Druffel ◽  
...  
Keyword(s):  
Small Sample ◽  
Small Samples ◽  
Chemical Extraction ◽  
Mass Ratio ◽  
Sample Analysis ◽  
Sample Processing ◽  
Extraction And Separation ◽  
Research Activities ◽  
Processing Techniques ◽  
The University

The Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI) has developed protocols for analyzing radiocarbon in samples as small as ∼0.001 mg of carbon (C). Mass-balance background corrections for modern and 14C-dead carbon contamination (MC and DC, respectively) can be assessed by measuring 14C-free and modern standards, respectively, using the same sample processing techniques that are applied to unknown samples. This approach can be validated by measuring secondary standards of similar size and 14C composition to the unknown samples. Ordinary sample processing (such as ABA or leaching pretreatment, combustion/graphitization, and handling) introduces MC contamination of ∼0.6 ± 0.3 μg C, while DC is ∼0.3 ± 0.15 μg C. Today, the laboratory routinely analyzes graphite samples as small as 0.015 mg C for external submissions and ≅0.001 mg C for internal research activities with a precision of ∼1% for ∼0.010 mg C. However, when analyzing ultra-small samples isolated by a series of complex chemical and chromatographic methods (such as individual compounds), integrated procedural blanks may be far larger and more variable than those associated with combustion/graphitization alone. In some instances, the mass ratio of these blanks to the compounds of interest may be so high that the reported 14C results are meaningless. Thus, the abundance and variability of both MC and DC contamination encountered during ultra-small sample analysis must be carefully and thoroughly evaluated. Four case studies are presented to illustrate how extraction chemistry blanks are determined.

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