8 cont – the automatic volumetric flask – Metrohm 711 Liquino User Manual

Page 46

3.2 Tutorial

711 Liquino, Instructions for use

3.2.8

CONT – the automatic volumetric flask

A typical daily task is the preparation of standard solutions. Preparing serial
dilutions is often time-consuming and involves making calculations. The
CONT/volume fraction mode of the 711 Liquino allows this monotonous rou-
tine work to be automated.

Example: the preparation of a standard for the determination of chloride in
drinking water by ion chromatography. The sample to be determined has
chloride content of about 10 ppm. The standard concentrations should be in
the range 5 - 15 ppm.

Pipetting and adding the standard solution is no longer necessary as the
dosing device (Dosino 700) can be screwed directly on to the bottle con-
taining the standard solution.
All that needs to be done is to inform the instrument of the concentration of
the standard solution and required target volume (volumetric flask mark). Af-
ter the start the instrument will request the entry of the final content. The cor-
responding amount of standard solution is added automatically to the volu-
metric flask which then only needs to be filled up to the mark. At the next
start the next concentration in the serial dilution is entered.

Preconditions / Preparation

Define a dosing unit which corresponds to the tubing of the Dosino used.
This procedure is described on page 22.

Method editing

MODE

DOS NR

SELECT

•

The CONT mode must first be activated. This sets all method parame-

ters to standard values. Press the key and then key can be used to select a

value from a list. Press