AB 301-400

The design of the Metrohm antidiffusion tips with the antidiffusion valve makes it possible to carry out very accurate
dosing. The principle is a ‘pressure valve’ which opens synchronously with the movement of the Dosing unit piston (i.e.when the pressure in the tubing increases) and closes when the pressure in the tubing drops. This principle ensures that the volume flow stops abruptly when piston movement stops and no drop formation or titrant leakage occurs subsequently.
If this mechanism is not working properly then a volume different from that documented can leak from the antidiffusion tip after the dosing step. This ‘leakage’ may also cause a delayed stabilization of the measured signal and produce faulty and inaccurate results.
Metrohm recommends the use of the titrimetric volume test method described below as the Standard Operating Procedure for validating Metrohm antidiffusion tips (6.1543.200, 6.1543.130 & 6.1543.140, each with 62726.090 Antidiffusion valve).
This titrimetric volume test can be used for the following purposes:

• Quality assurance by the manufacturer
  
• Quality assurance of analytical or other measuring systems by the user
  

The described method is not an official reference method.

 AB_306_1_d.pdf (112 KB)

 AB_306_1_e.pdf (108 KB)