Both isolate and sorbent must be ionised for adequate retention to occur. Adjust sample to the appropriate pH for the type of extraction being used. A high concentration of salts or ions can interfere with the ion exchange mechanism. If the ionic strength is above 0.1 M, dilute the sample with water to reduce the ionic strength, or use an initial non-polar extraction to desalt the sample prior to ion exchange.
Ion exchange is a relatively slow interaction.
When using a LiChrolut extraction manifold, adjust the vacuum control valve to decrease the flow rate during sample application and elution. Secondary interaction of the bonded sorbent with nonpolar portions of the isolate can cause incomplete elution. In this case, addition of organic solvent to the elution solvent may improve recovery of the isolate. If the isolate cannot be eluted from the strong ion exchange sorbent, try to extract the compound using the weak ion exchange sorbents. Exposure to pH less than 2 or greater than 8 will not degrade the sorbent in the short time it takes to do a extraction.