Recovery assessment

Accuracy The percent recovery assessed Based on determinations at... 

An extraction recovery assessment is basically required for a good quality control. The most common procedure is to spike the sample to be analysed with known amounts of the chemical compounds of concern, and to determine the compound(s) after equilibration and extraction. It should be stressed that a good recovery of spiked compounds does not necessarily mean that a good recovery will be obtained for naturally bound compounds however, an extraction procedure which cannot quantitatively recover a spiked compound should be abandoned since it will certainly not be applicable to naturally bound compounds. 

We should examine logistics for RP waste which leads us to establish system of recovery, assessment and warranty of stable supply. 

Alternatively, and only if the extraction procedure does not change the matrix composition and appearance, the recovery experiment may be carried out on the previously extracted real sample by spiking, equilibration and extraction. However, the recovery assessment can often be overestimated and... 

First method about 2000 mg of sample were treated with HCl and extracted into toluene and cysteine, and back-extracted into toluene (88 5)% recovery assessed by two spikings of a CRM (PACS-1). The extract was dried with anhydrous Na2S04. The separation was by capillary gas chromatography (column of 25 m length, internal diameter of 0.53 mm stationary phase BP-1 (methylsilicone), 1.0 pm film thickness injection of 1 pL temperature of the injector of 200 °C, temperature of the ECD detector of 250 °C, colunm temperature of 90°C N2 as carrier gas at 12 mLmin and makeup gas type at 50.5 mLmin ). Calibration was by calibration graph with MeHgCl in toluene verified with a MeHgCl2 solution. 

Approximately 50% of the funding for BOEMRE s offshore program is from rental fees on OCS leases and cost recovery assessments. The remainder of the funding is from annual congressional appropriations. 

With the most common operating feed rate as the typical feed rate selected, the time period with the feed rate close to the typical feed rate and in the middle of the run was selected as the data basis for the heat recovery assessment, which is given in Table 9.3. Specific heat capacity data for each stream are obtained from the physical property database. At the same time, the fuel consumption for both charge heater and stripper reboUing heater are obtained from the historian and then converted to absorbed duty based on heater efficiency, which are 48.1 and 33.7MMBtu/h, respectively. 

At the onset of method development the appropriate concentrations of the sub-stock and spiking solutions may not be known, but estimates can be based upon the initial method development scheme and by considering what types of spiking solutions will be required for early sensitivity and recovery assessments. Also, to determine the required concentrations for these solutions, consideration must be given to the type of solvent and the volume of solution that will be used for any subsequent dilutions or for spiking the analyte into the control matrix (Section 9.5.6c). 

Similar to QC samples, recovery assessment samples are prepared by spiking 10 pL of the standard working solution into 990 pL extracted blank monkey plasma (supernatant) to make the final concentrations of 30,500, and 3760 ng/mL. 

Recovery assessment six replicates of QC samples (30, 500, and 3760 ng/mL) are used following sample preparation in Section 7.3.5 and LC-MS/ MS analysis in Section 7.3.6. Six replicates of recovery samples are analyzed directly on LC-MS/ MS. The recovery is estimated by comparing the... 

Establish the heat integration potential of simple columns. Introduce heat recovery between reboilers, intermediate reboilers, condensers, intermediate condensers, and other process streams. Shift the distillation column pressures to allow integration, where possible, using the grand composite curve to assess the heat integration potential. 

The most useful methods for quality assessment are those that are coordinated by the laboratory and that provide the analyst with immediate feedback about the system s state of statistical control. Internal methods of quality assessment included in this section are the analysis of duplicate samples, the analysis of blanks, the analysis of standard samples, and spike recoveries. 

Spike Recoveries One of the most important quality assessment tools is the recovery of a known addition, or spike, of analyte to a method blank, field blank, or sample. To determine a spike recovery, the blank or sample is split into two portions, and a known amount of a standard solution of the analyte is added to one portion. The concentration of the analyte is determined for both the spiked, F, and unspiked portions, I, and the percent recovery, %R, is calculated as... 

With a prescriptive approach to quality assessment, duplicate samples, blanks, standards, and spike recoveries are measured following a specific protocol. The result for each analysis is then compared with a single predetermined limit. If this limit is exceeded, an appropriate corrective action is taken. Prescriptive approaches to quality assurance are common for programs and laboratories subject to federal regulation. For example, the Food and Drug Administration (FDA) specifies quality assurance practices that must be followed by laboratories analyzing products regulated by the FDA. 

In a performance-based approach to quality assurance, a laboratory is free to use its experience to determine the best way to gather and monitor quality assessment data. The quality assessment methods remain the same (duplicate samples, blanks, standards, and spike recoveries) since they provide the necessary information about precision and bias. What the laboratory can control, however, is the frequency with which quality assessment samples are analyzed, and the conditions indicating when an analytical system is no longer in a state of statistical control. Furthermore, a performance-based approach to quality assessment allows a laboratory to determine if an analytical system is in danger of drifting out of statistical control. Corrective measures are then taken before further problems develop. 

Using Control Charts for Quality Assurance Control charts play an important role in a performance-based program of quality assurance because they provide an easily interpreted picture of the statistical state of an analytical system. Quality assessment samples such as blanks, standards, and spike recoveries can be monitored with property control charts. A precision control chart can be used to monitor duplicate samples. 

Another important quality assessment tool, which provides an ongoing evaluation of an analysis, is a control chart. A control chart plots a property, such as a spike recovery, as a function of time. Results exceeding warning and control limits, or unusual patterns of data indicate that an analysis is no longer under statistical control. 

Assessments of control, operabiHty and part load performance of MHD—steam plants are discussed elsewhere (rl44 and rl45). Analyses have shown that relatively high plant efficiency can be maintained at part load, by reduction of fuel input, mass flow, and MHD combustor pressure. In order to achieve efficient part load operation the steam temperature to the turbine must be maintained. This is accompHshed by the use of flue gas recirculation in the heat recovery furnace at load conditions less than about 75% of fiiU load. 

An assessment of the toxicity potential of chemicals used in EOR has been reviewed (181). A series of first-intent petroleum sulfonates derived from petroleum fractions were synthesized along with a series of od-soluble synthetic sulfonates. Their properties and preliminary od recoveries have been reported (182). 

The ways of assessing profitabihty to be considered in this section are (1) discounted-cash-flow rate of return (DCFRR), (2) net present value (NPV) based on a particiilar discount rate, (3) eqmvalent maximum investment period (EMIP), (4) interest-recovery period (IRP), and (5) discounted breakeven point (DEEP). 

Solid-wa.ste-filling plan. The specific method of filling will depend on the characteristics of the site, such as the amount of available cover material, the topography, and local hydrology and geology. To assess future development plans, it will be necessary to prepare a detailed plan for the layout of the individual solid-waste cells. On the basis of the characteristics of the site or the method of operation (e.g., gas recovery), it may be necessaiy to incorporate special features for the control of the movement of gases and leachate from the landfill. 

The influence of soil ageing on the recovery of POPs from spiked soil samples was also assessed. Spiked lettuce samples were subjected to in vitro gastrointestinal extraction to assess the bioavailability of Endosulfan compounds. All samples (soil and lettuce) were extracted using pressurised fluid extraction and analysed using gas chromatography with mass selective detection. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

Shock-recovery experiments by Gray [10] were conducted to assess directly if the strain-path reversal inherent to the shock contains a traditional microstructurally controlled Bauschinger effect for a shock-loaded two-phase material. Two samples of a polycrystalline Al-4 wt.% Cu alloy were shock loaded to 5.0 GPa and soft recovered in the same shock assembly to assure identical shock-loading conditions. The samples had two microstructural... 

G.T. Gray III, Shock Recovery Experiments An Assessment, in Shock Compression of Condensed Matter—1989 (edited by S.C. Schmidt, J.N. Johnson, and L.W. Davison), North-Holland, Amsterdam, 1990, 407 pp. 

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