Recovery rate chart

The Recovery Rate Chart reflects the influence of the sample matrix. Values from the analysis of a spiked and non-spiked sample are used. 

Different Control Charts Recovery Rate Chart -1... 

Proportional systematic errors are detected with a Recovery Rate Chart, but not constant systematic errors (e.g. too high blank values). Additionally the spiked analyte might be bound to the matrix differently. This possibly results in a higher recovery rate for the spike than for the originally bound analyte. 

X-/mean-charts 3 Blank value chart 3 Range chart with absolute ranges 3 Range chart with relative ranges 3 Recovery rate chart 3 Differences chart... 

Real samples that are analysed with and without a spike are used for the Recovery Rate Chart. It is necessary to consider, whether the sample used for control has a representative matrix and whether the spike is boimd to the matrix in the same way as the analytes in the sample. 

Trueness or exactness of an analytical method can be documented in a control chart. Either the difference between the mean and true value of an analyzed (C)RM together with confidence limits or the percentage recovery of the known, added amount can be plotted [56,62]. Here, again, special caution should be taken concerning the used reference. Control charts may be useful to achieve trueness only if a CRM, which is in principle traceable to SI units, is used. All other types of references only allow traceability to a consensus value, which however is assumed not to be necessarely equal to the true value [89]. The expected trueness or recovery percent values depend on the analyte concentration. Therefore, trueness should be estimated for at least three different concentrations. If recovery is measured, values should be compared to acceptable recovery rates as outlined by the AOAC Peer Verified Methods Program (Table 7) [56, 62]. Besides bias and percent recovery, another measure for the trueness is the z score (Table 5). It is important to note that a considerable component of the overall MU will be attributed to MU on the bias of a system, including uncertainties on reference materials (Figures 5 and 8) [2]. 

Figure 5.16, adapted from Kurihara,79 80 shows a comparison of several types of commercial reverse osmosis membranes in terms of salt rejection and permeate flow rate under seawater test conditions (35,000 ppm, 800 psi, 25°C). This chart emphasizes the capability of PEC-1000 to provide complete single-stage seawater desalting. In a test at Toray s Ehime desalination test facility on 42,000 ppm seawater (equivalent to Red Sea salinity), PEC-1000 spiral elements operated at 35% recovery produced a permeate having an average salinity of only 220 ppm, well below WHO standards. Average salt rejection was 99.5%. 

DIO. A distillation column operating at 2.0 atm is separating a feed that is 55.0 mol% n-pentane and 45.0 mol% n-hexane. The feed is at 65°C, and its flow rate is 1000 kmol/h. The distillate is 99.93 mol% n-pentane, and we want a 99.50% recovery of n-pentane. The system uses a total condenser, and reflux is a saturated liquid with an external reflux ratio of L/D = 2.8. There is a partial reboiler. Data are available in Problem 3.D6 and in the DePriester charts. Find D, B, Xg,... 

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