The LAMBDA lab peristaltic pumps and OMNICOLL fraction collectors are used together in liquid chromatography. LAMBDA lab peristaltic pumps are programmable and remote controllable to achieve linear, stepwise and segmented gradient elution.
The LAMBDA peristaltic pump supplies the liquid mobile phase continuously to the packed chromatography column at a consistent pulsation-free reproducible flow rate.
Isocratic elution requires one buffer and one peristaltic pump. However, gradient elution is carried out with two buffers and one or two peristaltic pumps:
"Biochemists recommend LAMBDA peristaltic pumps which guarantee pulsation-free application of liquid mobile phase"
Gradient elution with two pumps
Two LAMBDA peristaltic pumps are used to mix the eluents for gradient elution.
The change in the composition over time can be programmed directly on the LAMBDA pumps or it can be recorded and displayed as a real-time graph using the PNet PC control software.
PNet software allows to remote control the pumps and create the gradients.
The gradient mixture passes through the chromatography column and the components are separated.
The eluate from the column passed through the detector to measure the pH, absorption 280 nm and conductance.
Automated fraction collector LAMBDA OMNICOLL, fractionates the eluate and collects the fractions based on the programmed time or drop counter.
Gradient elution with one pump
Gradient elution can also be carried out with one peristaltic pump: the containers with elution buffer A & B are connected by a siphon or tube at the bottom with a valve to adjust the flow
Elution buffer A is consistently drawn into the well-stirred beaker with elution buffer B, where the buffer concentration being altered
Programmable LAMBDA peristaltic pump used to pump the gradient mixture into the chromatography column
The eluate from the column passed through the detector to measure pH, Absorbance 280 nm & conductance
From the detector, the eluate fractionation collected by the OMNICOLL fraction collector into the desired containers (e.g.: bottles, beakers, tubes, vials, etc.)
Requirements of pumping system for column chromatography
The most important requirements of the pumping system for column chromatography are:
Constant and reproducible flow rate (The reproducibility depends on the retention times of the peaks. The retention times are again dependent on the flow rate.)
Pulsation-free flow (The stationary phase has to be protected against pressure surges. The baseline of the detector should remain stable.)
Further information about chromatography, fraction collectors and connection of peristaltic pumps could be found at www.fractioncollector.info