Metrohm 711 Liquino - Manual (Page 46)

3.2 Tutorial
711 Liquino, Instructions for use 40
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
-
X
DOS NR
SELECT
P
• The CONT mode must first be activated. This sets all method parame-
ters to standard values. Press the <MODE> key and then <SELECT>
until ‘CONT’ appears in the display:
Di spl ay: mode sel ect : CONT
ENTER
YES • Press <ENTER>. The instrument is now in the CONT mode.
Di spl ay: CONT * * * * * * * *
r eady 0. 000 mL
PARAM
B
• The <PARAM> key is used to access the parameter menu, where all
the possible settings for a CONT method can be found.
Di spl ay: par amet er s
>CONT par amet er s
• The submenu ‘>CONT parameters’ contains the main settings for a
CONT method. Press <ENTER> to open the submenu.
Di spl ay: >CONT par amet er s
t ype: subst . conc.
• The colon indicates that the <SELECT> key can be used to select a
value from a list. Press <SELECT> until ‘volume fraction’ appears.
Di spl ay: >CONT par amet er s
t ype: vol ume f r act i on