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Question:Sample container search

warren is asking a question about spectrometry-sampling: Subscribe to answer questions on this topic

warren asked on August 14, 2014 21:38
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What I want to do

The square glass bottles we've used for fluorescence spectroscopy are sold out, and the nail polish bottles we've used are hard to get small enough and with flat sides. @mathew and I have been brainstorming some other options.

bottle

The literature review I've been doing mentions that it's best to let the laser pass through as little liquid as possible since the liquid can filter out the laser somewhat, and more importantly, the liquid can filter out the fluorescence emitted by the sample, like in this post by @eustatic:

filtering

Nanodrop and ultra micro cuvettes

@gaudi and @dusjagr's nanodrop research note, DIY Nanodrop and patent research by @mathew show a lot of options related to suspending a droplet somehow, either between two sheets of clear glass or plastic, or in some kind of hole:

glass

One thing I worry about is making a mess -- it's great if we can completely seal the sample so it doesn't get toxic sludge all over the spectrometer, or your hands, and so that samples can be stored and transported.

"Ultra micro cuvettes" narrow at the bottom for a 1mm beam path (the thickness of the sample), but until I found this type with a round top, we were worried about leakage -- square-topped cuvettes have to be kept upright or they leak.

These have round caps, are plastic, UV-friendly, and $84 per hundred pack, $372 per 500: http://www.spectrecology.com/Disposable_Cuvettes.html or here on Amazon: http://www.amazon.com/BrandTech-759230-UV-Transparent-Disposable-Ultra-Micro/dp/B003ULPARY

uvcuvets_x.jpg

These have a "chemical compatibility chart" here: http://www.brandtech.com/cuvette_comp.asp

It'd be too bad to use a specialty material, but we're already getting really particular about the jars, so they're not universally available either.

But Mathew and I talked today and we came up with the idea of something like a rigid Otter Pop, which could be made from plastic thermally sealed over a butter knife, more or less.

otter2.JPG

We could make them by sealing a roll of plastic (like a candy shop) every 1cm or so and cut it in half lengthwise, so they're open at one end. It'd be nice if we could use something rigid so they could slot in like a projector slide, and we could edge-light them with a laser. This needs to be tried out! @Mathew has a sandwich bag sealer :-)

IMG_20140814_172536.jpg

So we have a lot of things to try out, now!



spectrometer fluorescence cuvettes sample-containers sample-prep oil-testing-kit nano-drop

question:spectrometry-sampling



12 Comments

amysoyka about 3 years ago

Looks fun..icy poles are awesome.

I had this same problem a while back.

In the end I settled for resealable plastic baggies & plastic straws.

amysoyka about 3 years ago

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eustatic about 3 years ago

amy is that a plastic straw + curling iron?

amysoyka about 3 years ago

Yup.

^_^

mathew about 3 years ago

I love the straws! grabbed a stack myself today.

warren about 3 years ago

Amy, have you tried shining a laser through those? I had the odd experience today of finding a fish oil pill, and look what happens when you shine a UV laser through it! Very reminiscent of this poster, but could also be Vitamin E or A, according to them: http://publiclab.org/notes/warren/11-25-2013/poster-on-issues-with-pah-detection-in-fish

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warren about 3 years ago

Just mention it because the pill is filled with liquid, and reminded me of your straws.

mathew about 3 years ago

Gelatin capsules are super cheap, and gelatin is very transparent. they won't dissolve in oil, I don't think-- but they are water soluble. That would be a sweet container to use.

amysoyka about 3 years ago

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@warren As far as I can tell, kinda this was done with a cheap UV light - not a high intensity laser LED...

amysoyka about 3 years ago

Also some tips on the straws.

*Straws seal best of you wait until the tongs are hot and then put them in.

*To get liquid in them, flip, squeeze, dip, flip and shake.

@matthew So, how long until you start using tampons to absorb water pollution?

;)

jaia about 3 years ago

I love the price on these cuvettes from Carolina Biological -- $29.95 for a pack of 100. http://www.carolina.com/spectrophotometer-accessories/spectronic-plastic-semi-micro-cuvette-pack-100/

If leakage is a concern, why not just put something over the top? A small balloon? A condom?

mathew about 3 years ago

Ok- so styrene cuvettes are dissolved by diesel fuel and several other oils. In the photo below you can see the bottom dissolving into a sticky mess

IMG_20140919_154636.jpg

Also, Gel caps fluoresce and we can't use them either.

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