2
4.2 Dispensing By Volume: Parameter Guide,
1081 PharMed: #13, 14, 16, 25, & 17
The following information should be used as a general guide in selecting optimal dispensing
parameters This data was collected with a 600 RPM LabTec™ Dispenser mounted with a
1081 pump head; the “Tube Size” parameter refers to thin-walled PharMed™ pump
tubing sizes: 13, 14, 16, 25 & 17.
The “Slow Factor” is implemented at the end of each dispensing cycle to avoid overshooting of the tar-
get volume. Thus a Slow Factor of 1.00 mL indicates that the last 1.0 mL will be dispensed at reduced
pump speed. Typically, for dispensed volumes less than 50 mL, the “Slow Factor” is approximately 5%
to 10% of the selected Dispensed Volume. The “Sniffle, i. e. momentary pump reversal at the end of
the dispensing cycle, is set at its default value of 0.3.
Dispensed
Volume (mL)
Tube Size
Pump Speed
(Max. 600 RPM)
Slow Factor
Tpical Precision
(RSD)
Dispensing Time
/ Alliquot (RSD)
0.50 mL #13 50% 0.05 mL <0.5% 5.0 sec
1.00 mL #13 50% 0.05 mL <0.5% 7.0 sec
2.00 mL #13 75% 0.10 mL 0.5% 9.0 sec
4.00 mL #13 100% 0.20 mL 0.5%
12.0 sec
2.00 mL #14 50% 0.15 mL <0.5% 4.5 sec
4.00 mL #14 50% 0.20 mL <0.5% 6.5 sec
10.00 mL #14 75% 0.30 mL <0.5% 8.5 sec
20.00 mL #14 100% 0.40 mL <0.5%
11.0 sec
10.00 mL #16 50% 0.80 mL 0.5% 6.0 sec
20.00 mL #16 50% 1.00 mL 0.5% 9.0 sec
50.00 mL #16 75% 1.00 mL 0.5%
11.5 sec
100.00 mL
#16 100% 1.50 mL 0.5%
15.0 sec
50.00 mL #25 50% 1.50 mL 0.7% 8.0 sec
100.00 mL
#25 75% 3.00 mL 0.7%
12.5 sec
150.00 mL
#25 100% 4.00 mL 0.7%
13.0 sec
200.00 mL
#25 100% 5.00 mL 0.7%
14.0 sec
100.00 mL #17 75% 5.00 mL <1.0% 9.0 sec
200.00 mL
#17 100% 5.00 mL <1.0%
14.0 sec
400.00 mL
#17 100% 7.00 mL <1.0%
25.0 sec
500.00 mL
#17 100% 7.00 mL <1.0%
24.0 sec
Note: After changing pumping parameters, i.e. changing pump tubing, Pump Speed, Slow Factor
or Sniffle settings, you should re-calibrate the LabTec™ Dispenser (see Re-Cal feature) in order
to maintain a high accuracy / precision level.
Note: For each “Dispensed Volume”, ten (10) separate measurements were made; the average
“Dispensed Volume” the Standard Deviation and Relative Standard Deviation (RSD, %) as well as
the “Dispensing Time per Aliquot” were determined. Distilled water was used as a diluent; each
“Dispensed Volume” was verified by weight using a Mettler PG 5002-S, 0.01 gram resolution.
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