New pH-Buffer Tables and Systems

Although available buffer tables are extensive, they may fail to meet particular requirements, such as a specified ionic strength or a nominated buffer species. Where pAa values of the buffer substances are known the compositions of the solutions can be calculated as indicated below. Considerations governing the design of new types of buffer systems are also discussed. 

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The new system was applied for standard ethanol solutions prepared in phosphate buffer solutions (pH 7.0). Extracted ethanol solutions were also used with 10% (w/v) NaCl by NBR 13992 1997 from gasohol blends (12) (Brazilian Association Technical Standard). Table 3 shows the concentrations of the extracted ethanol solutions measured by HPLC and respective gasoholblends. This new integrated system biosensor-FIA was used for the range of 0.05-1.5 g of ethanol/L, and good results were obtained compared with the ethanol content measured by the HPLC standard method. 

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