Mobile phase and Sample Injection

[montana]

Hello,
Analysis of creatinine HPLC-DAD Plasma.

Can i inject a sample treated with ACN directly in HPLC , with mobile phase phosphate buffer pH 7, 1% MeOH.
Can i change the composition of the mobile phase, in way to replace the 1% MeOH by 1%ACN.

Thank you

[Consumer Products Guy]

When injecting a sample in strong organic solvent into a mostly-aqueous mobile phase, keep the sample injection volume SMALL.

[montana]

Thank you