This situation occurs routinely as chromatographic components elute into a continuous ion source. The proteins elute according to their hydrophobicity. The conditions are then changed to elute the purified nucleic acid. Hydrophilic molecules in the mobile phase will tend to elute first. For example, when cation exchange chromatography is used, cations will elute out last. The lanthanides elute in order of decreasing atomic number. Proteins with different numbers of polyhistidine tags elute differently from nickel-affinity resin. These smaller molecules spend more time in the column and therefore will elute last. A solvent is used in a closed loop to elute PVC from the waste. Meanwhile, the negative charged molecules will elute out first. Compounds elute in the carrier gas phase only. The most weakly charged compounds will elute first, followed by those with successively stronger charges. Instead, one could cleave in a section between the bead and the antigen to elute. Ringers lactate should never be used to elute an Rb-82/Sr-82 generator for this reason. At the end of the column they elute one at a time.