Chromatography Forum

I work on my some Shimadzu model of HPLC with SIL-10AD VP autoinjector. recent a few times i encountered a problem that there's no any peak responses from my injections. I've made sure that the problem is not from the column, lamp, or detector. what can I primarily do to check which part of the autoinjector causes this trouble? or any try to fix them by myself. (i work on normal phase solvent and mobile phase, using pure water to purge and rinse autosampler. Did they show any connection with the problem?)

any kind of answer will be appreciated

Check the line from your autosampler to the column is not blocked or loose, you wont see any leaks unless you're injecting but I'd run a few blanks even with a union attached and watch it when you hear it injecting. We had a similar problem a while ago with our Dionex system with an intermittant puddle and it was that so might be worth checking if you haven't already. I amn't familiar with the Shimadzu internal workings however I'd imagine if you opened the likely bit up and watched it you may be able to watch it when its injecting and determine which bit (if any!) are loose?

thank u, I'll try then. calling distributor may be the last choice

Did you see any leaks in the injector? Is your leak sensor doing ok?
I agree with the previous answer. Perhaps the injector solvent line is blocked, specially the inlet filter. When you purge the autoinjector, does any solvent came out? Try to sonicate it with hot distilled water and a little biy of 2-propanol. Or may be the needle is precipitated, and not sucking from the vial. you can check it by putting a vial and loading with 500 uL (if the injector lets you). Or check the valve, and the seat. Perhaps you´ll have to exchange it.
And I didn´t understand. Are you working on Normal phase, using n-Hexane? Because the injector solvent line shoul be on Isopropanol or n-Hexane when you are running.
Good luck then.