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Help us with a laboratory protocol
We process geologic samples in a mass spectrometer. There is a flaw in the protocol. Help us figure out a better way. Here's what we do:
1. Put small amount (measured in micrograms) of a sample into silver capsule. The silver capsule is a cylinder with one open end. It is very small, 2mm in diameter. After the sample is put in the capsule, the capsule is pinched shut and the top folded over twice.
2. Put capsule in the assay tray. Record on paper the position of the capsule. E.g. Cell A1 has sample from Site X. There are not identifying marks on the capsule itself.
3. The tray is 8 x 12, so as many as 96 samples might go in. Repeat 1 and 2 as needed.
4. Take tray to mass spectrometer. Put about 10-15 samples in mass spectrometer, leave the rest of samples in tray until the 10-15 are run.
The problem happens between steps 3 and 4. A couple of times, the tray has been knocked, causing the capsules to fall out. When this happens the information about which capsule contained a sample from which site it lost. For example, we don't know which capsule was in A1.
One thought was to stamp the capsule with the cell #, e.g. A1, before loading the sample, but this would not work because it would not be possible to undo the folding of the capsule to see the stamp. This also assumes we could get really small stamps.
1. Put small amount (measured in micrograms) of a sample into silver capsule. The silver capsule is a cylinder with one open end. It is very small, 2mm in diameter. After the sample is put in the capsule, the capsule is pinched shut and the top folded over twice.
2. Put capsule in the assay tray. Record on paper the position of the capsule. E.g. Cell A1 has sample from Site X. There are not identifying marks on the capsule itself.
3. The tray is 8 x 12, so as many as 96 samples might go in. Repeat 1 and 2 as needed.
4. Take tray to mass spectrometer. Put about 10-15 samples in mass spectrometer, leave the rest of samples in tray until the 10-15 are run.
The problem happens between steps 3 and 4. A couple of times, the tray has been knocked, causing the capsules to fall out. When this happens the information about which capsule contained a sample from which site it lost. For example, we don't know which capsule was in A1.
One thought was to stamp the capsule with the cell #, e.g. A1, before loading the sample, but this would not work because it would not be possible to undo the folding of the capsule to see the stamp. This also assumes we could get really small stamps.
Engrave the bottom of the silver with a small number. Use small engraving tool. The number will be hard to read but hopefully you will not have to read them often
ASKER
Thanks for the replies.
Unfortunately I think these won't work. To use colors, we need 96 colors, and someone able to distinguish them. Engraving on the bottom would require the skills of a surgeon.
Unfortunately I think these won't work. To use colors, we need 96 colors, and someone able to distinguish them. Engraving on the bottom would require the skills of a surgeon.
96 colors?
Why?
12 colors.
That's how transistors and resistors get done.
Each color that's not black or white represents a digit
White represents the beginning, black the end.
Each digit is represented by a color.
12 colors can thus represent an unlimited number--if you have the space.
2 mm in diameter -- but how long?
Why?
12 colors.
That's how transistors and resistors get done.
Each color that's not black or white represents a digit
White represents the beginning, black the end.
Each digit is represented by a color.
12 colors can thus represent an unlimited number--if you have the space.
2 mm in diameter -- but how long?
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Is there any reason the box can't have a tight cover when it is in motion.
Or a dab of a compatible adhesive to keep each sample in place?
Or a dab of a compatible adhesive to keep each sample in place?
ASKER
>it's terrible practice to have samples unlabled for any length of time at all
I know. That's why we're trying to fix it.
I know. That's why we're trying to fix it.
ASKER
I need to ask the mass spec guy if coloring the capsules will affect the results.
The cover is a good idea. Though there would still be some time when the capsules could be knocked out, a cover limits that time.
Adhesive: another idea I hadn't considered ... it have to be weak enough to be able to get the capsule back out. Any adhesive on the capsule may affect results, as well. Not sure.
The cover is a good idea. Though there would still be some time when the capsules could be knocked out, a cover limits that time.
Adhesive: another idea I hadn't considered ... it have to be weak enough to be able to get the capsule back out. Any adhesive on the capsule may affect results, as well. Not sure.
What about weak adhesive a la post-it notes on the tray?
The adhesive would stay on the tray, and the capsules would cling to it?
The adhesive would stay on the tray, and the capsules would cling to it?
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ASKER
d-glitch: The pill boxes are the best idea presented here.
TommyS*: The tube idea is also a good one.
Any substance such as ink, paint, or glue will not work because it will affect the results. The capsules are even handled with tweezers so as not to get oil from skin on them.
TommyS*: The tube idea is also a good one.
Any substance such as ink, paint, or glue will not work because it will affect the results. The capsules are even handled with tweezers so as not to get oil from skin on them.
In that case you certainly shouldn't have them touching each other. Ever. Glad you got a solution.
If this won't work then perhaps using smaller containers, just to hold enough samples for one spectrometer test so the rest can remain covered and can't get knocked. At most you would mix up 10-15 samples then so it should be an improvement.