Metrohm 746 VA Trace Analyzer - Manual (Page 97)

4 Introduction to the operation
746 VA Trace Analyzer / 747 VA Stand
4-12
• The sequence of the segment SegPb is explained in brief in what follows:
Line 1 Switching on the DME (dropping mercury electrode)
Line 2 Selection of the measurement mode DP (differential pulse)
with voltage amplitude –50 mV, voltage step 0.4 s, meas-
urement time 20 ms and pulse time 40 ms
Line 3 Voltage sweep of –200 mV ... –550 mV with a
voltage step of 6 mV
Line 4 Switch off voltage, current measurement and DME
Line 5 End of the segment (return to main program)
3 Switch to dialog page "SUBSTANCES"
• Press the yellow key. The dialog page "SUBSTAN-
CES" appears with the parameters for evaluation of the substance lead:
Method: TESTPb SUBSTANCES
Pb - SegPb
Recognition Display / Plot
ДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДДДД
U.verify -380 mV I.scale auto
U.tol (+/-) 40 mV U.div 50.00 mV/cm
U.width min 25 mV U.begin mV
U.width max 120 mV U.end mV
I.threshold 200 pA
Baseline Evaluation
ДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДДДД
Type linear Mode VA
Scope whole Quantity I.peak
dU.front auto Sign. digits 4
S.front auto
dU.rear auto
S.rear auto
Modify
column
Modify
line
Select
subst.
Link to
segment
Delete
subst.
Subst.
name
>>
The header of the dialog page "SUBSTANCES" contains the name of the substance
Pb and the segment SegPb linked with this substance. This is followed by the
parameters for substance recognition (Recognition), baseline calculation (Baseline),
evaluation quantity (evaluation) and curve representation (Display/Plot).
You will find further information regarding this dialog page in section 5.6.3.
• The following is a brief explanation of the most important parameters:
U.verify Characteristic voltage for lead: –380 mV
U.tol Tolerance for characteristic voltage: only peaks with
a peak voltage of –380 V
± 40 mV are recognized
U.width min Minimum peak width: only peaks with a
peak width > 25 mV will be recognized
U.width max Maximum peak width: only peaks with a
peak width < 120 mV will be recognized
Type Baseline type: linear (tangent)
Scope Baseline range: entire curve