Sample minimum size

The maximum flowrate recommended for the given collection method. Sampling may be done at lower rates as long as minimum sample size is met. 

The minimum sample sizes currently recommended by CRM producers are generally =ioo mg (IAEA-TECDOC-825/880 1995/1996). These minimum sample sizes were developed for determinations made primarily on dissolved samples. There are, however, some CRMs available that may permit the successful use of much smaller sample aliquots as discussed in the examples below. 

Brands proposed a calculation method in the case of segregation A special type of inhomogeneous, particulate objects is the surface analysis by microscopic techniques e.g. analytical electron sj troscopy, laser induced mass spectroscopy or proton-induced X-ray emission. Here the minimum sample size can be translated into the minimum number of specific sample points in the specimen under investigation. 

Minimum sample size Culture media Incubation time Incubation temp. ... 

There are a variety of methods for determining the bulk chemical composition of a sample. Each has its strengths and weaknesses. The choice of which technique to use depends on the elements of interest, the methods to which you have access, and the funding that is available for the analysis, among other things. The minimum sample requirement of the technique is an important consideration, but it can be very misleading. The true minimum sample size is the size that adequately accounts for the chemical and mineralogical complexity of the sample. 

MS sensitivity depends on both the type of instrumentation and the nature of the analytes, but, typically, a minimum sample size of 5-10 ng is in most cases sufficient. Limited sensitivity in a certain application is often not due to the inherent sensitivity of the MS but rather the level of background impurities that are in the isolate. It is not always appreciated that very slowly eluting LC solutes from previous separations can create substantial MS background peaks that obscure analyte identification. Thus, it is important to use a blank sample to ensure that the background of the trapped fraction is adequately free of possible interferences to the desired identification. 

SABRE Method. Acronym for Simulated Approach to Bayesian Reliability Evaluation. An advanced approach to designing a reliability test program developed at PicArsn, the objective of which was to design a test program of minimum sample size for artillery fired atomic projectiles. Called the SABRE method, the program uses mathematical modeling, Monte Carlo simulation techniques, and Bayesian statistics. It is a sophisticated system devised to test items that cannot be tested because of their atomic nature. The aim is to determine the risk factor and to predict what will happen when the projectile is fired... 

Due to the variability in the pharmacokinetic parameters seen in earlier studies, no formal sample size justification was given for 12 subjects per population. However, according to the draft guidance for industry by the US FDA 12 subjects is the typical minimum sample size for a bioavailability comparison (US FDA December 1978, US FDA December 2002). This was fulfilled here for each of the strata male, female, younger, elderly. 

Infrared spectra of 1- to 3-/ gram samples of pure chlorinated insecticides have been obtained by the micro-KBr disc method (2,8). The minimum sample size is determined by traces of unremovable impurities. These impurities cause difficulties in analyzing pesticides in fatty biological materials, such as some foods (3). Published work on the analysis... 

Minimum spatial resolution is given by the difiraction limit. In the IR spectral range, approximately 10 pm may be achieved. In an uptake experiment, however, the minimum sample size is rather limited by the signal-to-noise ratio. Thus, typical areas are 40 x 40 pm. ... 

A reference material is produced so that each unit allows repeated measurements. It is necessary to verify that all test portions in the unit of (C)RM are identical at least for the parameter to be measured. The within-vial inhomogeneity is the basic investigation on the validity of the homogenisation procedure. It will also have the objective to determine, if possible, the minimum sample intake. As already discussed above the minimum sample size often corresponds to the limit of determination of the method rather than the real inhomogeneity level of the material. The determination of the minimum sample size and a first view on the homogeneity can be obtained already on the bulk material before packaging. The final assessment must be performed on the packed material. 

As a final result the producer issues a material certified for a number of parameters, based on the minimum sample size determined in the homogeneity study. This information must be given to the end user in the form of a certificate. The certificate or the accompanying report must also state the uncertainty and the way it is calculated. 

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