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Blank ideal

The detection limits are calculated as three times the standard deviation obtained from the measurement of ten blanks. Ideally, we should have measured these detection limits from multiple measurements of a pure copper material to take into account the contribution of the copper matrix to the background, but we did not have such a material. This may imply a slight underestimation of the detection limits for some elements. The detection limits range from about 1 ppb for bismuth to 2 ppm for iron (Figure 2). [Pg.341]

The performance curve presents graphically the relationship between the probability of obtaining positive results PPRy i.e. x > xLSp on the one hand and the content x within a region around the limit of discrimination xDIS on the other. For its construction there must be carried out a larger number of tests (n > 30) with samples of well-known content (as a rule realized by doped blank samples). As a result, curves such as shown in Fig. 4.10 will be obtained, where Fig. 4.10a shows the ideal shape that can only be imagined theoretically if infinitely exact decisions, corresponding to measured values characterized by an infinitely small confidence interval, exist. [Pg.115]

An ideal method for the preconcentration of trace metals from natural waters should have the following characteristics it should simultaneously allow isolation of the analyte from the matrix and yield an appropriate enrichment factor it should be a simple process, requiring the introduction of few reagents in order to minimise contamination, hence producing a low sample blank and a correspondingly lower detection limit and it should produce a final solution that is readily matrix-matched with solutions of the analytical calibration method. [Pg.303]

The Bottom of the curve should ideally equal zero, if appropriate blank assays have been included in other words, v should equal zero when [S] is zero. [Pg.105]

The normal way of determining recoveries is to spike analyte standards into a blank sample matrix (one not containing the analyte) and compare these with standard solutions. The best way to obtain such a blank sample is to synthesise the API using a different route that cannot give rise to the impurity to be measured. Alternatively, a sample can be highly purified to eliminate the analyte. Such a blank sample may not be available, in which case standard addition may be required. Here, different levels of the analyte are spiked into the sample and the response can be measured from the slope of the resulting line. This can be compared with the results from standard solutions. Ideally, recoveries will be more than 80%, although in difficult analyses this may not always be achievable. [Pg.118]

The sensitivity of the method is limited by the reproducibility of the filter blanks. These blanks originate both from sulfide absorbed during filter impregnation and diying, and from unknown matrix contamination which is not removed by washing the filters. In our own work, we have found that under ideal conditions variability in the filter blank yields a practical detection limit of 1 x 10"10 moles S per filter. [Pg.334]

If the blank or background value of the paper is low, and this is the result of correct rinsing, photometry of the eluate is done in ideal circumstances, and a spectrophotometer increases the accuracy of the readings. [Pg.70]

Good ideal Anyone producing receiver blanks or similar "almost finished ordnance" should submit samples for review,... [Pg.83]

Figure 6-5 illustrates a portion of a list of polymer research samples and some of their physical properties. To use AutoFilter, first select the complete list or a partial area to be examined if the list is separated from the rest of the worksheet data by blank cells, you need only select any cell within the list. Choose Filter from the Data menu and then choose AutoFilter from the submenu. Excel adds drop-down arrow buttons to row 1, which ideally should contain column labels. [Pg.136]

The stoichiometric equivalence point should be immediately detectable. This usually requires a large change in some physical or chemical property of the solution. This point in the reaction is often located by means of a secondary system, which provides an observable endpoint. This secondary system must be reproducible, clearly identifiable, and ideally coincident with the stoichiometric equivalence point. Because coincidence is not always achieved, the difference between the endpoint and the equivalence point should be easily measurable. Often, so-called blank solution is used for this correction. A chemical indicator... [Pg.3753]


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See also in sourсe #XX -- [ Pg.187 ]




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