Metrohm 730 Sample Changer - Manuel (Page 58)

3.6 User Methods
730 Sample Changer, Introduction 55
Method: pH cal
This method serves to complete an automated series of pH measurements preceded
by electrode calibration. It can be used with the Metrohm 713 and 692 pH Meters.
Special beakers must be defined for this in the first rack positions during rack configu-
ration (spec.1 = 1
st buffer solution, spec.2 = 2 nd buffer solution, spec.3 = rinsing
beaker). This method shows the mode of operation when using spray nozzles com-
bined with aspiration of the rinsing fluid.
'pa
730 Sample Changer 0120/02 187 730.0013
parameters
method pH cal
number of samples: rack
>start sequence
1 CTL:Rm: INIT
2 MOVE 1 : spec.3
3 LIFT: 1 : work mm
4 PUMP 1.* : 4 s
5 MOVE 1 : spec.1
6 LIFT: 1 : work mm
7 STIR: 1 : 10 s
8 CTL:Rm: METER cal pH
9 SCN:Rm : End1
10 MOVE 1 : spec.3
11 LIFT: 1 : work mm
12 PUMP 1.* : 4 s
13 MOVE 1 : spec.2
14 LIFT: 1 : work mm
15 STIR: 1 : 10 s
16 CTL:Rm: METER enter
17 SCN:Rm : End1
18 MOVE 1 : spec.3
19 LIFT: 1 : work mm
20 PUMP 1.* : 4 s
>sample sequence
1 SHIFTRATE: + 20
2 MOVE 1 : sample
3 LIFT: 1 : work mm
4 STIR: 1 : 10 s
5 CTL:Rm: METER mode pH
6 CTL:Rm: START device1
7 SCN:Rm : End1
8 SHIFTRATE: – 20
9 MOVE 1 : spec.3
10 LIFT: 1 : work mm
11 PUMP 1.* : 4 s
>final sequence
1 MOVE 1 : spec.3
2 LIFT: 1 : work mm
>changer settings
rack number 0
lift rate 1 25 mm/s
lift rate 2 25 mm/s
shift rate 20
shift direction: auto.
beaker test mode: single
on beaker error: MOVE
…
- number of samples (entire rack, only positions where a
beaker is placed are counted)
- rinsing beaker in front of tower 1
- rinse electrode
- first buffer solution in front of tower 1
- immerse electrode
- stir for 10 seconds
- start pH meter calibration
- wait for measurement of the first buffer (EOD pulse)
- rinsing beaker in front of tower 1
- rinse electrode
- second buffer solution in front of tower 1
- immerse electrode
- stir for 10 seconds
- start measurement in second buffer
- wait for end of measurement (EOD pulse)
- rinsing beaker in front of tower 1
- rinse electrode
- turning direction of the rack (ascending)
- sample beaker in front of tower 1
- immerse electrode
- stir for 10 seconds
- switch pH meter to pH measurement and start it
- the result is printed out
- wait for end of measurement (EOD pulse)
- turning direction of rack (descending)
- rinsing beaker in front of tower 1
- rinse electrode, suck off rinsing liquid
- turning direction of the rack at the beginning (calibration)
automatic
Remark: The turning direction of the rack is altered during method processing to pre-
vent the electrode, during rack rotation, from dripping into samples that have
not yet been analyzed.