This page might help to solve your solid phase extraction (SPE) challenges.
|Improper conditioning.||Condition column according to phase: Reversed phase: use methanol, acetonitrile or isopropanol followed by solvent used for sample solution. Ion exchange: use methanol or isopropanol followed by a buffer at a pH which charges both sorbent and analyte.|
|Analytes have a greater affinity for the sample solution than for the column.||Choose a column having a greater selectivity for analytes.|
Change pH of sample to increase affinity of analytes to sorbent.
Change polarity of sample to produce lower affinity for the analytes.
|Improper washing.||Wash column using appropriate wash solution.|
|Poor elution.||Increase eluent volume, increase eluent strength.|
Decrease elution strength of washing solvent.
|Analytes have stronger interaction with column sorbent than with eluting solvent.||Choose a column that is less retentive for the analytes.|
|Elution volume is too low.||Increase the elution volume.|
|Elution solvent is too weak to disrupt analyte interaction with the column.||Change pH of eluting solvent to ensure greater affinity for the analytes.|
Change polarity of eluting solvent to ensure greater affinity for the analytes.
|Column dries before sample added.||Re-condition column.|
|Capacity of column is exceeded.||Decrease sample volume.|
|Sample loading flow rate is too high.||Use a column with a larger amount of sorbent.|
Decrease flow rate.
|Elution flow rate is too fast.||Allow elution solvent to seep into column before aspirating or forcing through column.|
Apply in two separate aliquots versus a single aliquot.
|Using too strong a wash solution to remove interferences.||Reduce strength of wash solvent.|
|Elution volume is too small.||Increase volume of elution solvent.|
|Interferences are extracted at the same time as analytes.||Selectively wash interferences from column prior to elution.|
Use a column which retains the analytes more than the interferences.
|Interference is due to leachables from column.||Wash column with eluting solvent prior to conditioning.|
|Excessive particulate matter in sample.||Filter or centrifuge sample.|
|Sample solution is too viscous.||Dilute sample with a weak solvent.|
|Inadequate vacuum.||Increase vacuum.|
|Sample volumes larger than extraction column capacity.||Use larger extraction column volumes.|
|Improper methodology.||Consider a different extraction mechanism, sorbent, or format.|