Columns specific

Sugar analysis by hplc has advanced greatly as a result of the development of columns specifically designed for carbohydrate separation. These columns fall into several categories. (/) Aminopropyl-bonded siHca used in reverse-phase mode with acetonitrile—water as the eluent. (2) Ion-moderated cation-exchange resins using water as the eluent. Efficiency of these columns is enhanced at elevated temperature, ca 80—90°C. Calcium is the usual counterion for carbohydrate analysis, but lead, silver, hydrogen, sodium, and potassium are used to confer specific selectivities for mono-, di-, and... 

Example 5 Calculation of the SR Method Use the SR method with the PR equation of state for K values and enthalpy departures. The oil was taken as n-dodecane. To compute stage temperatures and interstage vapor and hquid flow rates and compositions for ahsorher-column specifications shown in Fig. 13-52. Note that a secondary ahsorher oil is used in addition to the main ahsorher oil and that heat is withdrawn from the seventh theoretical stage. 

The conditions required to minimize tube dispersion are clearly indicated by equation (10). Firstly, as the column should be operated at its optimum mobile phase velocity and the flow rate, (0) is defined by column specifications it is not a variable that can be employed to control tube dispersion. Similarly, the diffusivity of the solute (Dm)... 

These data bases will provide, first, the column specifications and, second, the analytical specifications. A diagram representing the overall design protocol is shown diagramatically in Figure 1. 

The optimum mobile phase velocity will also be determined in the above calculations together with the minimum radius to achieve minimum solvent consumption and maximum mass sensitivity. The column specifications and operating conditions are summarized in Table 4. 

Numerous application examples are related to gel filtration (e.g., see Hagel, 1989 Hagel and Janson, 1992 Pharmacia, 1991). A selected number of applications are discussed with respect to their goals and to types of methods and SEC media attributes, which impact the selection and or construction of a suitable SEC column. Specific examples of these various applications types are given later under Sections II,C and III. The optimization of running conditions to achieve the desired results are discussed in Section VI. 

This chapter describes the use of three commercially available SEC column types for the characterization of nonionic, anionic, and cationic, synthetic water-soluble polymers. These include TSK-PW, Synchropak, and CATSEC columns. Specific examples and experimental procedures are discussed for each type of column. Elowever, the major emphasis is on the use of TSK-PW columns due to their broad applicability for a variety of water-soluble polymers. 

Make a dimensioned sketch of your design and fill out the column specification... 

Figure 2. Ultrastyragel GPC column specifications based on polystyrene standards, toluene as mobile phase (iml/min).

The information provided by the three data bases allow the column to be designed and the column specifications to be calculated. Furthermore, once the column has been designed, and its properties defined, a complementary set of analytical specifications can also be determined. 

The column design protocol, therefore, consists of three data bases, performance criteria, elective variables and instruments constraints. These data bases will provide, firstly, the column specifications and finally, the analytical specifications. A diagram representing the overall design protocol is shown in figure (1). The four different components of the column design protocol will now be discussed in detail. 

Column specifications expressed as (length X ID, particle size manufacturer) when reported in original publication. n = number of determinations LoD = limit of detection CV = coefficient of variation. 

Column specifications expressed as (length x ID, particle size manufacturer) when reported in original publication. 

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