Bio-Rad ddPCR™ Supermix for Probes - Manual (Page 15)

QX200 Droplet Generator Instruction Manual | 7
Chapter 2 Droplet Generation
QX200 Droplet Generator Instruction Manual
Air bubbles can cover the bottom of the well and result in 2,500–7,000 fewer droplets and poor
data quality. They are difficult to see. To avoid creating air bubbles, use the following pipetting
technique, which also ensures samples wet the bottoms of the wells so they are wicked into the
microchannels (necessary for proper droplet generation).
■ ■
Use only 20 μl aerosol-barrier (filtered) Rainin pipet tips; do not use 200 μl pipet tips (see Table 1.2)
■ ■
Gently slide the pipet tip down the side of the well at a ~15° angle until it passes over the ridge near
the bottom. Holding the angle, ground the pipet tip against the bottom edge of the sample well while
slowly dispensing a small portion of the sample; do not pipet directly onto the side (wall) of the well
■ ■
After dispensing about half the sample, slowly draw the tip up the wall while dispensing the rest of the
sample; do not push the pipet plunger past the first stop
3. Dispense the droplet generator (DG) oil in the reagent trough (see Table 2.1 for volumes required; see
Table 1.2 for PCR supermix and DG oil compatability).
2. Transfer 20 μl of each prepared sample to the sample wells (middle row) of the DG8 cartridge.
Table 2.1. Droplet generator (DG) oil requirements.
# Wells Volme of Oil
8 700 μl
24 1,820 μl
48 3,500 μl
96 6,860 μl
DG8 cartridge
Reagent trough and droplet generator oil.
Transferring sample to the sample wells (middle row) of the DG8 cartridge. Hold the pipet tip at a 15° angle and at the bottom of
the well (middle and right panels); do not dispense sample onto the wall or side of the well.
15° angle
Tip
Ridge in well