Metrohm 746 VA Trace Analyzer - Manual (Page 414)

5.7.3 Alphabetical instruction list
746 VA Trace Analyzer / 747 VA Stand
5-263
Method PSA_wine SEGMENT
Pb
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Instructions t/s Main parameters Auxiliary parameters
––––––––––––– ––––– ––––––––––––––––––––––––– –––––––––––––––––––––––––
1 DCTMODE t.step 0.30 s t.meas 40.0 ms
2 MEAS 60.0 U.meas -800 mV
3 ØSTIR
4 PSAMODE
5 PSWEEP 11.0 U.start -800 mV Resolution 100 /V
t.depos 5.0 s
6 END
The illustrative program for the determination of lead with PSA runs as
follows:
OPERATION SEQUENCE Main program
Line 1 Addition of sample
Line 2....4 Switching on the RDE, application of a voltage
of –200 mV
Line 5....6 Addition of HCl and Hg(II) solution
Line 7...13 Preparation of the electrode, regeneration with
CONDC and formation of the Hg film in the
preparation segment Prp-800
Line 14...22 Double standard addition for lead determina-
tion
Line 15...19 Replication of the lead measurement in the
segment
Pb
SEGMENT Prp-800 Preparation of the electrode
Line 1....6 Formation of the mercury film
SEGMENT Pb Determination of lead
Line 1....3 Deposition of lead at –800 mV for 60 s with
stirring
Line 4....6 Deposition of lead at –800 mV for 5 s without
stirring, then PSA measurement
see also PSAMODE, MEAS, RDE, HMDE, CONDC