pH and column use

<p>Are the limits of columns and system in terms of gradient solvent usage (pH and plastic-dissolving solvents) also applicable to injection diluents?</p><p></p><p>We're working with water's HSS column (with an upper pH limit of 8).  Am I correct in my rationalization that since our mobile phase is ph 2.5 it is safe to inject samples with pH >8 without harming the column?  Or are the samples not diluted as much as I think before they hit the column?</p><p></p><p>Also in terms of a system that is not upgraded for hexane usage, is it safe to inject a sample containing ~ 0.1 mL/mL toluene or other plastic-dissolving solvents?  Thanks.</p>