Several Problems Affecting the Flow Rate of the SPE Cartridges
The basic operation of SPE cartridges includes five steps: activation, balance, sampling, wash, and elution. Generally speaking, those matters affecting the velocity of the SPE cartridges arise in these steps. Here we especially talk about the process of activation and balance. In that process, people fill the fillers at first.
In general, reversed-phase or ion-exchange columns are activated and balanced by methanol and water respectively, while normal-phase columns are activated by petroleum ether or n-hexane.
First, filling too tight results in slow flow rate. People can solve these matters through increasing the flow rate under pressure or purchasing products from manufacturers with strict quality control of convection rate.
Second, when the size of the fillers is smaller, the flow rate will be slower. People need to select the proper size of columns according to the type of sample matrix and the usage habit.
The third is the difference in the pipe volume. Obviously, the large diameter and the low height of the fillers means the fast flow rate. The selection of the columns with suitable pipe volume is also based on the type of sample matrix and the usage habit.