The MANTIS is capable of dispensing reagents with viscosities up to approximately 10 cP without requiring custom software settings. Working with reagents with viscosities above 10 cP can cause hanging drops as well as inaccurate dispense volume and coefficient of variation (CV). To prevent those issues, both the pressure and timing settings need to be adjusted when dispensing reagents with viscosities of around 15 cP (see the list of reagents below).
Note: These procedures will not work for PFE and 3PFE chips. It is strongly recommended to use silicone LV and HV chips to dispense viscous reagents. For more information about chemical compatibility with FORMULATRIX chips, click here.
List of reagents with viscosities approaching to 15 cP (20 oC):
PEG 1000, 40%
PEG 3350, 28%
PEG 4000, 25%
PEG 8000, 18%
Glycerol, 60%
Selecting the correct viscosity for your reagent results in more precise dispenses, as viscous liquids require different dispense and delay times from non-viscous liquids. The MANTIS has been programmed to handle liquids of different viscosities according to their specific properties.
On the Tools menu, click Reagent List.
In the Viscous? column, specify the viscosity of the reagent you have selected. Select Yes if your reagent is viscous. A reagent is considered viscous if its viscosity is between 10 and 15 cP. Otherwise, select No.
Selecting Reagent Viscosity in the Reagent List
You can slightly increase the pressure and vacuum applied to the diaphragms when using the diaphragm chips, and you can increase the bottle pressure when using the continuous flow (CF) chip.
Note: Pressure settings can only be applied to MANTIS V3 and later.
Go to the Tools menu and select Reagent List.
Select a reagent in the Reagent Name column and click the HV Continuous Flow tab.
Click Show Advanced Options.
Reagent List
Adjust the diaphragm pressure and vacuum as well as the CF bottle pressure, as follows:
Important: DO NOT exceed 21 psi for Pressure Chip or -18 inHg for Vacuum.
Tips: Using a pipette input is better for viscous dispensing.
- For continuous flow dispensing, increase the Pressure Bottle value until your desired results are achieved.
Important: DO NOT exceed 18 psi for the Pressure Bottle. The pressure difference between chip and bottle pressure must be a minimum of 5 psi. For example, the default value for chip pressure is 12 psi. If the bottle pressure exceeds 7 psi, you must increase the chip pressure accordingly.
Note: You should recalibrate the CF whenever you change the Pressure Bottle.
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