Enrichment Factor EF

A common approach for identifying the enriched elements in a material is to calculate the enrichment factor (EF). The EF of an element, M, is obtained by comparing its concentration with that of a reference element, R, such as cerium or... 

To estimate the contribution of wind-blown dust of crustal origin to the fine aerosol concentration, elemental enrichment factors were calculated using the method of Macias et al. (20). The enrichment factor, EF., for an element i was calculated as follows ... 

Here the relative concentrations are expressed as the enrichment factor (EF) rather than the weight/weight concentration (i.e., Pg/g) because we cannot in every case accurately weigh the particles on the stages. The EFs are approximately proportional to the relative mass concentrations, and have the added interpretive value of showing the chemical enhancement with... 

Several studies have shown that the concentrations of many organic pollutants in fog water are much higher than would be expected from the compound s equilibrium air/ water partition constant (see Chapter 6), Kiaw (= gaseous concentration of compound i in the air/dissolved concentration of compound i in pure bulk water). In order to describe the observed enrichment of compounds in fog water, an enrichment factor EF can be defined (see Goss, 1994 and references cited therein) ... 

Whenever possible, amodel selection should be optimized before starting selections with a library. In this experiment, a mixture of active and inactive phage-enzymes is used as a model library for one round of selection. The phage mixture is analyzed before and after selection, yielding numbers that serve for the calculation of an enrichment factor (EF) ... 

Figure 15.2. Concentrations and enrichment factors (EF) of EHCH in seawater ( ) and...

Figure 15.5. Correlation between average log Kov value of tri- ( ), tetra- ( ), penta- (A), hexa- ( ), hepta- (o) and octa-chlorobiphenyls (A) and corresponding average enrichment factors (EF).

The relative importance of the different sources can be confirmed by considering enrichment factors (Ef) ... 

Table 8-1. Concentrations (mg kg ) and Enrichment Factors (EF) for samples of Taraxacum officinale collected in three European cities.

For the particle filters we have determined enrichment factors (EF) using Wedepohl s (11) crustal values and the equation ... 

Enrichment factors (EF) were computed using aluminum and sodium as reference eelements for the earth1 s crust (4) and seawater ( 5), respectively. Enrichments were calculated by... 

Because of this behaviour, individual seawater constituents can be utilised for source apportionment studies in non-marine environments. For instance, an enrichment factor EF) for a substance X is defined as... 

This issue is addressed by the enrichment factor EF (Equation 3.2). This descriptor takes into account the improvement of the hit rate by a VS protocol compared to a random selection ... 

Seawater abundances (from Wilson, 1975), (X)/(Na) ratios, and enrichment factors (EF) are shown [EF = (X)/(Na)acrosol/(X)/(Na)seawater], Aerosol data are from Table 7-13. h From Hoffman et al. (1974), not included in Table 7-13. 

High phase ratios applicable, resulting in higher enrichment factors (EF). 

In principle, all effective FI continuous precipitation systems with dissolution may be used to achieve some degree of analyte preconcentration. The only prerequisite is that enough sample is available. Within limits defined by the capacity of the precipitate collector, the enrichment factors EF will be proportional to the amount of sample processed. The efficiencies of different preconcentration systems, however, may be quite different. A quantitative evaluation of the efficiencies of the systems may be made using the criteria originally proposed for on-line column preconcentration methods. i.e., in terms of CE and CL These are calculated for the various methods collected in Tables... 

SML can have an enrichment effect of SVOCs, most likely due to their hydro-phobic character and great affinity for surfactants collected at the air-water interface (Hardy 1982 Chernyak et al. 1996 Wurl et al. 2006a). This effect can be quantified by the enrichment factor EF, calculated as the ratio between SML and... 

Fig. 4 Enrichment factors (EF) of PAHs and OCPs in the sea-surface microlayer of Singapore s coastal line (error bar for standard deviation)...

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