Usually it is sufficient to dry and filter the eluents overnight using a molecular sieve. System breakdowns The HPLC system as a whole consists of mechanical parts which may become contaminated by the solvent. The pump as well as manual and automatic injection systems may produce abrasion particles that flow through the whole system and which may reach the column. Such particles can also originate from 0-rings, rotors and plastic rings. For such non-polar eluents it is also difficult to keep the water content constant.
Possible consequences are changes in retention time and selectivity.
Addition of dioxane may be a solution to this problem. Silica columns and columns of medium polarity are shipped in n-heptane. The handling of reversed-phase columns is much less problematic due to their shorter equilibration times. For conditioning, 10-20 column volumes will mostly suffice. Shortened and irreproducible retention times in most cases are the result of insufficient or wrong conditioning.