I have an older tech when performing an acid elution will use the same pipette for washes 1-3 to remove supernatant. The tech uses a new pipette for wash #4. I have never seen this before. I don't believe this is correct, but I am unable to find any reference material. Do any of you have an opinion or possible reference?

You're concerned about "carry-over" ?  Probably the only reference to use of pipettes would be in the DFU from the manufacturer, but I suspect that they would not be that specific. Testing the "Last Wash" in parallel with the eluate is supposed to control the issue of adequate washing and/or carry-over.

Our facility uses semiautomatic aspirators on which the stainless steel tip/needle is seldom changed, but sometimes flushed with tap water (if obviously bloody). Never had a problem.

Is the "older tech" getting valid results ?

Using a new pipette each time is how I keep track of how many times I've washed!..........4 washes with Working Wash? - Lay out 4 pipettes!........AND close my drawer so I won't - out of habit - reach in and get one! LOL!

(I'm and "older tech" too!  )

 

but as to your question........I don't know the true answer......... we always use a new one.  But, if it does not state specifically in the IFU and their eluates / LW's give valid results.........I'd say it doesn't matter..........???

1 hour ago, Bet'naSBB said:

 "Lay out 4 pipettes!"

Genius !

Thank you for you responses. I was always taught to use a clean pipette, but the IFU doesn’t state specifically. I wasn’t trying to get the older tech in trouble just saw something that was different. Thank you again.

I guess if there was carry-over it is the same as  using the same tube during the whole washing process.

41 minutes ago, Yanxia said:

I guess if there was carry-over it is the same as  using the same tube during the whole washing process.

EXCELLENT point!

On 8/30/2024 at 8:23 AM, Bet'naSBB said:

Using a new pipette each time is how I keep track of how many times I've washed!..........4 washes with Working Wash? - Lay out 4 pipettes!........AND close my drawer so I won't - out of habit - reach in and get one! LOL!

(I'm and "older tech" too!  )

 

but as to your question........I don't know the true answer......... we always use a new one.  But, if it does not state specifically in the IFU and their eluates / LW's give valid results.........I'd say it doesn't matter..........???

This is EXACTLY what I do. That way you can continue your juggling act without worrying about what wash you are on! 

Never have I ever done this for eluate preparation.  Never had a problem.  But, I like the way the 4 pipette people think!