allen s e 1974 chemical analysis of ecological materials

... Press LLC Of the ion-selective electrodes other than glass electrodes, the fluoride electrode is the most successful. It is well-behaved, relatively free of interferences, and has an adequately ... chemical species and a vastly increased data throughput. These developments pose some challenges. Because of the lower detection limits of some instruments, it is now possible to see quantities of ... that are used on water. In this section several specific aspects of water analysis are addressed. Physical Properties Measured in Water The commonly determined physical properties of water are color,...

Ngày tải lên: 23/07/2013, 20:57

... range of the system, dilute the extract with acetonitrile and reanalyze. 12.8 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required. 13. ... analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery ( ) and the standard deviation of the percent recovery (s ). Express the accuracy p assessment ... established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance,...

Ngày tải lên: 14/02/2014, 03:20

... wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery ( ) and the standard ... This type of detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section ... compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance,...

Ngày tải lên: 14/02/2014, 03:20

... characteristic masses in the EICPs must fall within ±20% of the relative intensities of these masses in a reference mass spectrum. The reference mass spectrum can be obtained from a standard analyzed ... the parameters of interest and achieves all acceptable performance criteria (Section 10) may be used. GC to MS interfaces constructed of all glass or glass-lined materials are recommended. Glass ... calibration. the baseline to valley height between the isomers is less than 25% of the sum of the two peak heights. Otherwise, structural isomers are identified as isomeric pairs. 13. Calculations 13.1 When...

Ngày tải lên: 05/03/2014, 21:20

... range of the system, dilute the extract and reanalyze. 11.7 If the measurement of the peak response is prevented by the presence of interferences, an alternative gas chromatographic procedure is ... be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery ( ) and the standard deviation of the ... column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation...

Ngày tải lên: 05/03/2014, 21:20

... because of widespread resistance and because of extended persistence of residues in kidney tissues. Aminoglycosides are used to treat individual animals for therapeutic purposes rather than metaphylaxis ... food-producing species is associated with food safety concerns. The genotoxic and carcinogenic nature of carbadox and its metabolites and the presence of relatively persistent residues in edible tissues of ... aminoglycosides is mediated through bacterial enzymes (phosphotransferases, acetyl- transferases, adenyltransferases), which inactivate amino- glycosides and prevent their binding to the ribosome. Genes encoding...

Ngày tải lên: 11/03/2014, 03:20

... wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery ( ) and the standard ... reanalyze. 12.7 If the measurement of the peak response for benzidine is prevented by the presence of interferences, reduce the electrode potential to +0.6 V and reanalyze. If the benzidine peak ... depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification...

Ngày tải lên: 14/03/2014, 20:20

... the system, dilute the extract and reanalyze. 12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required. 13. Calculations 13.1 Determine ... established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, ... Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit...

Ngày tải lên: 14/03/2014, 20:20

... MIV s microfinance assets are predominantly debt instruments, as has been the case for the last six years. Of microfinance assets held by MIVs in 2010, debt investments represent 82%, followed ... their relative resilience. The market is emerging from the crisis with a more realistic sense of the inherent risks of the business, particularly in competitive environments, and the sudden ... a web-based analytical service of MicroRate that provides professional investors and researchers with the necessary tools to identify, assess, and monitor MIVs that meet their individual requirements....

Ngày tải lên: 16/03/2014, 17:20

... chromatograms. 12.8 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze. 12.9 If the measurement of the peak response is prevented by the presence of interferences, further ... established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes References 1. Fine, D.H., Lieb, D., and Rufeh, ... proven effective in the analysis of 1,2 wastewaters for the parameters listed in the scope (Section 1.1). A nitrogen-phosphorus detector was used to develop the method performance statements in Section...

Ngày tải lên: 22/03/2014, 14:20

... the EICPs must fall within ±20% of the relative intensities of these masses in a reference mass spectrum. The reference mass spectrum can be obtained from a standard analyzed in the GC/MS system ... current profiles. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section ... this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA...

Ngày tải lên: 28/03/2014, 19:20

... wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the spandard ... assess the precision of the environmental measurements. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies. 9. ... interference restricts the sensitivity of the GC/MS analysis, the analyst should employ additional cleanup procedures and reanalyze by GC/MS. 12.10 In those circumstances where these procedures...

Ngày tải lên: 28/03/2014, 20:20

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Ngày tải lên: 10/07/2014, 23:20

Ngày tải lên: 10/07/2014, 23:20

Ngày tải lên: 10/07/2014, 23:20

... of the shear stress indicate the plane on which the stresses act. For stresses shown in Fig. 2.1, this is the plane whose normal is parallel to axis-z. The second subscript of the shear ... nevertheless governed by the same general laws and principles of mechanics whose brief description is given below. 2.1. Stresses Consider a solid body referred to Cartesian coordinates as in ... the stressed state of a solid. 2.3. Stress transformation Consider the transformation of a stress system from one Cartesian coordinate frame to another. Assume that the elementary tetrahedron...

Ngày tải lên: 22/03/2014, 12:20

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Ngày tải lên: 27/06/2014, 18:20