Relative standard deviation, in the

The resulting metal, in the salt state, is dissolved in nitric acid and diluted to a known volume with double distilled water. The solution is analyzed by Atomic Absorption for the metals of interest. Metals such as Cadmium, Berylium and Nickel have very low threshold limit values which are set by OSHA and are frequently present in the sample in very low quantities. Many Atomic Absorption units are equipped with a hollow graphite tube atomizer which increases the sensitivity dramatically making it easier for the analyst to obtain reliable results for species present in the sample in very low concentrations. The validity of the metal fume data depends on sampling train calibration and the precision and accuracy of the analytical procedure. NIOSH has reported a 2% relative standard deviation in the analytical method which has been collaboratively tested. 

Table 3-4 shows the relative standard deviation in the retention of the same analyte on all columns. For ionized analytes eluted very close to the void volume, the retention difference between all columns is significant, but for analytes retained on the column, the RSD of is much smaller than k and essentially within the experimental error range. 

Mass Balance Considerations. The values of ER for the Fischer assay spent shale are contained in Table V. If it is assumed that the relative standard deviation in the analyses is 10%, then the relative probable error in ER would be 14% if the analytical errors were indeterminant and 20% if the errors were determinant (38). The mass ratio of OS-l/FS is 1.24 as derived from the assay data in Table I. It is not possible to conclude that any trace elements are mobilized from the solid material during the assay retorting. The ER results obtained for arsenic, selenium, and molybdenum indicate the importance of analytical precision in detecting any trace element mobilization during oil shale retorting. The values of RI contained in Table V show a similar dependence on analytical precision. The probable errors in these values are also between 14 and 20% if the relative standard deviation in the analytical results is assumed to be 10%. These results indicate that, within experimental error, none of the trace elements have been lost during Fischer assay. More definitive conclusions on whether elements are mobilized or lost can only be reached with more precise analytical... 

To find the absolute standard deviation in a product or a quotient, first find the relative standard deviation in the result and then multiply it by the result. 

Calculate the relative standard deviation in the computed molarity of 0.0200 M HCl if this acid was standardized against the masses derived in Example 16-1 for (a) TRIS, (b) Na2C03, and (c) N32B407 IOH2O. Assume that the absolute standard deviation in the mass measurement is 0.0001 g and that this measurement limits the precision of the computed molarity. 

The data plotted as curve A in Figure 26-10 were obtained from calculations similar to those in Example 26-4. Note that the relative standard deviation in the concentration passes through a minimum at an absorbance of about 0.5 and rises rapidly when the absorbance is less than about 0.1 or greater than approximately 1.5. 

Pixel-to-pixel variation was measured at x = 150 and 250 on the SIT target among 10 pixels at each x position. Relative standard deviations in the intensities were found to be 3.3% and 3.5% respectively. 

Calculate the absolute and relative standard deviations in the counting rate for (a) the first entry in fable 32-2 and (b) Ihe mean of all of the data in the table. 

Since the relative standard deviation in the analyzed pulse height cr /E is equal to an/n, the contribution to energy resolution from ionization statistics can be computed as... 

The unbiased estimate of the relative standard deviation in the calculated true rate It is... 

Figure 4.56 The normalized relative standard deviation in the measured input rate with an ideal livetime clock operating for a specified real time t. (Reprinted by courtesy ofEG G ORTEC.)...

Since the residence time varies between the channels, a tracer pulse at the inlet of the microreactor will be broadened similar to the case for a tubular reactor with axial dispersion. As a first approximation, the relative standard deviation in the residence time is twice the relative standard deviation in the channel diameter [9] ... 

Proceeding as above, we calculate the relative standard deviation in the computed molar concentrations of 30.00 mL, 40.00 mL and 50.00 mL of 0.0200 M HCl and the results are shown in the table that follows. 

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