Some nonionic sample can be analyzed with the use of deionized water as an
Eluent. As the
Eluent, either a saltaqueous solution or buffer solution with or without a polar organic solvent added to it. The followings are how to select the
Eluent to be used.
1) Ionic and nonionic hydrophilic samles. Salt solutions or buffer solutions are generally used as the
Eluent. Typical aqueous salt solutions are as follows:
CAUTION (1) Use of salt concentration in the range of 0.05M to 0.3M is recommended. Maxinium usable salt concentration is 0.5M. (2) pH of
Eluent should be 3.0 to 10.0. (3) pH of
Eluent should be higher than 6.0 when the
Eluent contains chloride ions. (4) Boric acid buffer solution is not recommended because di-ol groups of packing material and boric acid make a complex.
2) Nonionic and ionic hydrophobic samples Addition of polar organic solvents in the
Eluent is recommended to decrease the hydrophobic adosorption. Addition of salts in the
Eluent is also recomended when the sample is ionic. Upper limit of concentration of polar organic solvents are as follows: and
Flow rate should be slower than 0.5mL/min when in-
Column solvent is changed to an
Eluent containing polar organic solvent. In the case of DMSO,
Flow rate should be slower than 0.3mL/min and
Column temperature should be 50°C or higher.
3) Protein samples Urea and 6M guanidine aqueous solutions, which are commnly used as protein modifier, can be used as the
Eluent containing surfactants, such as SDS or Brij-35, is recoummended for the samples, such as membrane proteins, of which solubility in water is poor.
CAUTION Frequent replacement of the in-
Eluent from normal solvent to the above solvent will make the
Column life short. In such case, it is recommended to use one colunm specifically for the purpose.