pFI in Lab-on- valve Format:
Stopping the Flow

The miniaturized pFI  uses lab-on-valve manifold (A), equipped with two miliGAT pumps (P1,P2), two thermostated holding coils (H1,H2) and an externally mounted flow cell (FC) to automate reagent based assays at microliter scale by stopped flow technique.

Stopping the flow is powerful tool that is designed to trap reacting sample zone in a selected part of the flow path. This approach does not only provide an unlimited period for incubation, but also allows monitoring of reaction rate in real time.

Stopping the flow while the reacting mixture is within the holding coil, the SHC technique yields a response similar to the peak obtained by cFI. The movie clip (B) shows gradual formation of a red reaction product  inside the coil, followed by rapid washout at the end of stop flow period.

Stopping the flow while a sample is in the flow cell, the SFC technique allows reaction rate measurement to be monitored in real time. The movie clip (C) shows gradual formation of the red dye within the flow cell, and rapid washout at the end of monitoring period. (1.2.33.)