Metrohm 746 VA Trace Analyzer User Manual
Page 129
4 Introduction to the operation
746 VA Trace Analyzer / 747 VA Stand
4-44
Method: INTSTD .mth OPERATION SEQUENCE
Title : Pb determination with internal standard (Cd)
Instructions t/s Main parameters Auxiliary parameters
ДДДДДДДДДДДДД
ДДДДДДДДДДДДД ДДДДД
ДДДДД ДДДДДДДДДДДДДДДДДДДДДДДДД
ДДДДДДДДДДДДДДДДДДДДДДДДД
ДДДДДДДДДДДДДДДДДДДДДДДДД
ДДДДДДДДДДДДДДДДДДДДДДДДД
1 D SMPL>M V.fraction mL V.total L
2 C (CAL
3 C CSOLN>M addition into MEAS
4 DOS>M Soln.name Acetate V.add 1.000 mL
5 RADD>M Soln.name CdRefSol V.add 0.100 mL
6 PURGE
7 STIR 180.0 Rot.speed 2000 /min
8 ØPURGE
9 (REP
10 STIR 5.0 Rot.speed 2000 /min
11 SEGMENT Segm.name DPASV
12 REP)2
13 C RINSE Cycles 1 V.rinse mL
14 C CAL)3
15 END
Modify
column
Modify
line
Delete
instr.
Insert
instr.
Method
labels
•
The following is a brief explanation of the main program sequence:
Line 1
Addition of sample: 10 mL
Line 2
…
…14
Loop for recording the calibration curve (4 calibration solutions)
Line 3
Addition of calibration solution to measuring vessel: 10 mL
Line 4
Addition of acetate buffer to measuring vessel: 1 mL
Line 5
Addition of the internal standard to the measuring vessel:
0.1 mL Cd standard solution 1 mg/L
Line 6
…
… 7
Purging and stirring of the analysis solution for 3 min
Line 8
Switching off the purging
Line 9
…
…12
Loop for double replication of the segment
Line 10
Stirring of the analysis solution for 5 s
Line 11
Call-up of the segment
DPASV for lead determination
Line 13
Resetting of the volume bookkeeping to 0 for solution change
(new calibration solution)
Line 15
End of main program
•
The sequence of the main program depends on the selected mode for
the program run
Run mode
on the "MONITORING" page:
−
In the program run mode
calibration
, all instructions marked with
D
are ignored. Internal standard is added to 4 calibration solutions in
turn and lead and cadmium measured each time. The proportional-
ity factor between lead and cadmium is determined from the re-
corded calibration curve.
−
In the program run mode
determination
, on the other hand, all in-
structions marked with
C
are ignored. Internal standard is added to
the sample and then lead and cadmium measured. The lead mass
concentration is calculated using the proportionality factor deter-
mined beforehand.