proper flushing an HPLC system

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

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Hello everyone!
Which is the best way/best rinsing solution used to wash a HPLC system between different testing methods of biological samples(matrix)? We often face with pump leak and we suspected an improper procedure of system cleaning. In our lab. we used only approved CE kits and all mobile phases used are polar (water, MeOH, ACN).
Someone with experience in clinical laboratory could give me some advice or some bibliography/link recommendation?
Many thanks in advance!
I think that we need more info to be able to give a coherent answer.
Column type
Mobile phase composition
Temperature
Gradient program
Sample type

If you have an aqueous buffer, eg phosphate, you should flush entire system with water to avoid crystallization of phosphate in the pump heads, mixing valves etc.

Regards,
JMB
If you are using buffers you need to flush any line that contained buffer after every sequence with water, 5 min purge per line to be safe.You also need to run your seal wash with 10% meoh in water during and or after each sequence. (or your pump seals will eventually salt up and fail)
If you never use buffers, you dont really need the seal wash feature.

If you are running only reverse phase methods you could run 100% B (organic) to clean off your column after each injection (this should already be in your gradient method)
If you observe issues, you need to run the system under the initial conditions of the method for 10-15 min or so while observing the baseline. Also run blanks-always- they tell you how your hardware is performing. Run 5 blanks, print out the fifth (best, flattest) if flat and use that as your "baseline" for future runs to know your system is ready for samples
Not enough info to answer question... "bibliography/link recommendation?", I do not think so as this is related to training in performing chromatography.

In general, you select a wash solution based on what YOU are using in your system. The "wash" solution must be fully soluble with all samples being injected and any/all buffers used. The "wash" solution should have some organic content to inhibit the growth of undesirable bugs too. You may need more than one wash solution to do the job (and that is OK). Don't forget the column too! You need to develop proper column wash solution which can be run after each method to both reduce any buildup and rinse them for use. Do not incorporate 'column wash' steps into your analytical method (novice mistake). Instead, use separate column wash methods which can be linked to the analysis method. This provides more flexibility in how they are used and is just better procedure overall.

Lastly, you should be washing the entire HPLC system flow path down with the wash solution(s), pure water and some organic at the end of each day to remove any remaining "stuff" (that is a technical term) from the system and leave it in a solution which has at least 20% organic content (again, depends on the methods you use, but perhaps 50/50 MeOH/Water).
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