For HPLC – For Users of HPLC Systems

Buffer Solution Preparation Mode (W-AD/ W Series only)

• Recipes for 13 commonly used buffer solutions are included as standard
  Preparation recipes for commonly used buffer solutions are provided as standard.
  e.g. disodium phosphate, sodium acid citrate
• New buffer solution recipes can be registered
  If a buffer solution is not registered by default, it can be newly registered.
• Instructions are shown on the display
  The target weighing value is shown on the display and analog bar in order to compare the target with the current weight. Manual calculation is not needed.
• Record function
  Record output with date, time and operator name.

The pH level of mobile phase (eluent) solutions used in liquid chromatographs is adjusted to improve separation of components and extend the life of columns. This pH adjustment process is performed using a buffer solution.
Currently, the most common method is using a pH meter to measure the pH as the solution is prepared; however, this process requires considerable time and effort, which can cause operational bottlenecks.
An alternative method does not require a pH meter. It involves preparing solutions by weighing fixed theoretically calculated quantities of an acid and base.
AP series supports weighing these acids and bases. If the type and quantity of the buffer solution are specified, the balance displays the type and quantity of sample that should be weighed. Then the buffer solution can be prepared easily by adding water to the specified quantity of sample weighed accordingly.

Preparation example:

When weighing and preparing 50 mM of di-sodium hydrogen phosphate, 2-hydrate and 50 mM of sodium dihydrogenphosphate, 2-hydrate in order to prepare 3 L of 100 mM phosphoric acid (sodium) buffer solution at pH=2.1: