Metrohm 894 Professional CVS semiautomated - Manual (Page 7)

Application Bulletin 401/1 e
Installation instruction for 894 Professional CVS semiautomated
5.2. Brightener determination
5.2.1. Manual operation
•
Dosing Unit «894/D1 50mL VMS» connected to Dosino
1 has to be prepared with VMS.
•
Dosing Unit «894/D2 2mL Brightener» connected to
Dosino 2 has to be prepared with brightener
concentrate.
•
Dosing Unit «894/D3 2mL Suppressor» connected to
Dosino 3 has to be prepared with suppressor
concentrate.
•
The correct «Sample amount» has to be pipetted into
the measuring vessel when requested.
5.2.2. Workplace
•
Select sample type S AMPLE in the «Run» window of the
«Workplace» to run a determination.
•
Define the volume of sample used for the determination
under «Sample amount» in the «Run» window of the
«Workplace».
5.2.3. Course of events
•
The execution of the determination by modified linear
approximation technique is controlled by the 894
Professional CVS and viva.
•
The intercept solution is automatically prepared at the
beginning of each determination, by dosing VMS from
Dosino 1 and suppressor concentrate from Dosino 3.
•
After the determination of the intercept value, a window
will pop up prompting to add the sample on top of the
intercept solution. The exact sample volume has to be
pipetted manually through the pipetting opening of the
894 Professional CVS.
•
Standard addition is carried out automatically with
brightener concentrate from Dosino 2.
6. Remarks
6.1. Storing dosing units
When the dosing units are not used (during the night, over
the weekend) the dosing cylinder has to be rinsed with
water. Otherwise elemental copper can be formed or
additives can precipitate between the valve disk and the
distributor disk or in the tubings. A blockage can damage
the 800 Dosino. Emptying the cylinder and filling it with
water is sufficient to prevent a blockage.
6.2. Storing electrodes
When the electrodes are not used (during the night, over the
weekend) the electrodes should be thoroughly rinsed.
Working and auxiliary electrode can either be stored in
deionized water or dry. The reference electrode should be
stored separately in a vial filled with deionized water (KCl
solution, in case KCl is used as bridge electrolyte), so that
the reference electrode immerses at least to the rim of the
electrolyte vessel.
6.3. Waste bottle
The waste bottle must not be closed completely. For
pressure balancing in the waste bottle, keep at least one
opening unsealed. Overpressure would lead to a
malfunction of the 800 Dosinos.
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