Polyethylene Pipettes (Single use?)

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coominya
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Polyethylene Pipettes (Single use?)

#1 Post by coominya » Sun Apr 22, 2018 1:11 am

I bought a pack of 10 of these a month ago and got stingy and just reused them over and over, dipping into the same tank to draw out protist samples. Is there a downside to this? I just ordered 50 more as they are very cheap but I don't want to throw them away after each use unless there is a valid reason.

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Crater Eddie
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Re: Polyethylene Pipettes (Single use?)

#2 Post by Crater Eddie » Sun Apr 22, 2018 1:23 am

I reuse mine many times. Sometimes I'll bleach them out, but only when I worry about cross contamination between sample jars, which is not very often.
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MicroBob
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Re: Polyethylene Pipettes (Single use?)

#3 Post by MicroBob » Sun Apr 22, 2018 12:55 pm

It depends very much on what you do.
If you are a professional scientist and write in an article that there are fossile marine diatoms and radiolaria in the fresh water ponds around your house, your reputation might suffer somewhat. :lol:
As an amateur you just enjoy what you find and always keep in mind how many corners you cut in your process and how dependable your results are.
If you make a sensational find one day and your process was amateurish, you will not be sure whether your find was real.
I probably would overlook all available sensational finds because I don't have the backgroud knowledge to recognise them. So I don't have to work to scientific precision. But even I had the experience that I found certain rare diatoms in samples where I wouldn't have expected them, but where they could be. :roll: I will never know whether they are really from this sample or whether I "enriched" the sample.

One possible way to cope with this is to have a rubbish-box and a "to be cleaned properly"-box. The ingredients from the latter can be cleaned when the box is full and go back into use.

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coominya
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Re: Polyethylene Pipettes (Single use?)

#4 Post by coominya » Sun Apr 22, 2018 1:12 pm

MicroBob wrote: One possible way to cope with this is to have a rubbish-box and a "to be cleaned properly"-box.
Yes, I already have a container for slides and cover slips. I'm not too concerned though, it was a beginners dumb question.

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mrsonchus
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Re: Polyethylene Pipettes (Single use?)

#5 Post by mrsonchus » Sun Apr 22, 2018 6:20 pm

coominya wrote:
MicroBob wrote: One possible way to cope with this is to have a rubbish-box and a "to be cleaned properly"-box.
Yes, I already have a container for slides and cover slips. I'm not too concerned though, it was a beginners dumb question.
Same here - I use them a lot, and always re-use them. I also as you suggest have a 'to clean' tray, I call it my 'washing-up tray'.

John B.
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coominya
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Re: Polyethylene Pipettes (Single use?)

#6 Post by coominya » Sun Apr 22, 2018 9:41 pm

mrsonchus wrote: Same here - I use them a lot, and always re-use them. I also as you suggest have a 'to clean' tray, I call it my 'washing-up tray'.

John B.
One question that may be of more importance is what do you wash up with and is there a rinsing regime you follow? I was using dish detergent but I suspect I was leaving traces on slides because of a lack of water tension causing my droplet samples to spread out across the slide. I know you do botanical work so this mightn't be an issue for you but with protists it might as the cover-slip tends to settle a lot closer to the slide with less water tension.

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mrsonchus
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Re: Polyethylene Pipettes (Single use?)

#7 Post by mrsonchus » Sun Apr 22, 2018 10:03 pm

coominya wrote: One question that may be of more importance is what do you wash up with and is there a rinsing regime you follow? I was using dish detergent but I suspect I was leaving traces on slides because of a lack of water tension causing my droplet samples to spread out across the slide. I know you do botanical work so this mightn't be an issue for you but with protists it might as the cover-slip tends to settle a lot closer to the slide with less water tension.
I usually wash them with as you mention washing-up (dish) liquid then tap-water rinse then DI water, finally heated fan-air-dried in my slide drying cabinet.
I have about a dozen long glass pipettes which I use mainly for alcohol or histoclear - I colour-code the bulbs with a band of permanent marker pen. These I also dry in the same way. I use glass shortie pipettes from dropper bottles for small applications of stains etc - the I keep dedicated and occasionally wash with either acid or alkali depending upon which stain they've been in.

As you say though, using minute quantities with your living samples is a completely different case; I can see why surface-tension will be a major factor with this application.

John B.
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MicroBob
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Re: Polyethylene Pipettes (Single use?)

#8 Post by MicroBob » Mon Apr 23, 2018 10:54 am

coominya wrote: causing my droplet samples to spread out across the slide.
We might swap - this is what I usually want but not allway acheive when I make diatom slides! :lol:

I think there is more to glass than what we see. It makes a difference for example, when I move a cover slip through an alcohl flame. Fluids spread better afterwards.

So far I haven't found a really quick and effective process for cleaning of slides. Since I don't like to throw things away I will continue to llok for one.

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coominya
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Re: Polyethylene Pipettes (Single use?)

#9 Post by coominya » Mon Apr 23, 2018 11:45 am

MicroBob wrote:
coominya wrote:

So far I haven't found a really quick and effective process for cleaning of slides. Since I don't like to throw things away I will continue to look for one.
I toss mine in a petri dish full of tap water, then every 4 days or so clean them with hand soap under a tap and dry with paper towel. A micro-dishwasher would be great :lol: but I don't generate enough to warrant such. One thing I don't have is a dust free storage for them but I just bought this and will array them in it.

https://tinyurl.com/ydbnrj7v

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