Clean an hplc?

A simple question (but in my lab there is great confusion and I'm tired of this .. There was a big discussion that did not lead to anything):
-can you tell me the right wash for hplc to be done at the end of an analysis? We use very concentrated buffer phases on the Arc and Alliance.
When to use water? And ch3oh / h2o? ch3cn / h2o?
- What washing solution to use during an analysis.
Thanks from a novice analyst with bad and confused teachers.


  • As a rule of thumb for post-run washes, when using strong buffers, first wash out the system for at least 90 minutes, and with the column temperature high, with 90% Water:10% Organic so set up a washdown method with the gradient set to for example Line Seal wash to flush through system at a curve of 1 for instant conditions. Then a second line with 100% Organic for about an hour and then stop flow. But keep in mind that there will still be buffer sitting in your buffer line ( a few cm from the sinker to pump outlet ) so at the first chance you get, also dip this line into 90:10 and prime the line out for about 10-20mins before putting it back into the buffer. 

  • BL_
    edited July 2018
    It really depends on your line of work and if you have the luxury of time.

    After analysis: 2h 10-90% ACN gradient (it doesn't really matter if you use ACN or MeOH).

    time             flow      10% ACN line   90% ACN line
    0                  0.5             100                   0
    60                0.5             100                   0
    70                0.5              0                     100
    120              0.5              0                      100
    121              0                 0                      100

    Before you start the analysis 

    All lines in water
    WetPrime (Alliance) or Prime Solvent (ARC), 10 minutes, all channels.
    Flow to 1.0 ml/min, 5 minutes (remove the column beforehand)
    Stop flow put lines into appropriate solvents that you will use for analysis

    Prime lines you will use for analysys, 50:50 (if using two channels), 10 minutes
    Flow to 1.0 ml/min, 5 minutes (no column yet)
    Stop flow, put on column, apply initial conditions via Monitor/Setup

    You don't really use a "Washing solution" during an analysis however make sure that your Seal Wash line is in appropriate solvent (10% MeOH) and not running dry! "Needle wash" is substance and not system related and is very dependent on the analytical procedure used.