Labeling of
Samples for Chemical Processing
5
Mar 2003
Hello,
Has anyone on this forum managed to find premade chemical-resistant
tags to use when extracting cellulose? My thought is that small glass
tags would be ideal, but I can't locate any. I know that Pete van de
Water and others have hand-etched and punched out hard plastic discs,
but
the use life of these is fairly short. Also, my experience with exterior
labeling of the extraction pouches has not been good. Any ideas? Ed
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Dr.William E. Wright Postdoctoral Fellow Lamont-Doherty Earth Observatory
of
Columbia University 61 Route 9W Palisades, New York, USA 10964-1000
Phone:
(845) 365-8441 FAX: (845) 365-8510 / / / /:/ / / / / / / / / /./ / /
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5 Mar 2003
Ed
I usually use colored glass beads (easily found at any craft store)
tied with dental floss. I use a binary system red is 0 and blue is 1
and line up the bead according to the sample number. Leo.(Sternberg)
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5 Mar 2003
I can help with your question. In the Ehleringer lab, we take a thin
Pyrex rod, etch along the rod to make small labels, and then with a
Dremmel tool, label each section with a letter or number designation.
Then we break the glass at the etchings and heat the beads to 500 C
(smooths the edges so no one gets cut). This produces nice beads that
can be used over and over again. Plus these do not break down to affect
your sample.
Cheers,
Joy (Ward)
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5 Mar 2003
We just write on the beaker (the white labeling area) with a pencil.
It can be removed with a pencil eraser.
(Xiahong Feng)
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5 Mar 2003
William,
I personally use small glass
beads. They are inexpensive and you can find them easily (e.g. Wall-Mart).
You can play with color and beads number to make a code with a lot of
combinations. You can thread them on the dental floss used to close
the bag or put them directly in the pouch.
Stephane (Ponton)
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5 Mar 2003
Hi Everyone,
Since we create bags from ANKOM filter paper (pore size 50 (+/- 15)
microns, made from nitrogen free polyester), we can mark the edges using
a pig ear clipping technique. This is similar to Leo's binomial glass
bead approach. We can uniquely number over 75 bags this way. If anyone
is
interested in the clipping codes, I would be happy to send them.
I have also heard of people moving to microtechniques for extraction
where the entire cellulose extraction takes place in a eppendorf tube,
thus each tube can be uniquely marked. I haven't done this myself, but
perhaps others might like to comment on these microtechniques.
Renee
************
J. Renee Brooks
Western Ecology Division
U.S. EPA/NHEERL
200 SW 35th St.
Corvallis, OR 97333
(541) 754-4684 (Office)
(541) 754-4799 (FAX)
Brooks.ReneeJ@epa.gov
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5 Mar 2003
Hi Ed,
I have gone to a bagging system where no tags are required. They tend
to take up a great deal of volume in the bag and reduce the number of
samples I can batch process. I have also gone to a longer bag than has
multiple pockets. Essentially the bags are made with 6 pouches in a
row and a coding system cut into the bag at one end. The coding end
is next to pouch 1 and the remaining pouches are in consecutive order
(2 thru 6). After the pouches are all loaded they are all sealed along
the top and cuts are made (as many as 6 cuts although more are possible)
to identify the group. This is difficult to envision and if you want
I can send you a file with the coding scheme. This system allows me
to provide unique codes for about 400 samples, but I could envision
more if additional cuts are introduced. I have undergraduate students
unloading my samples and they think it is a good system and have not
had any difficulty identifying samples. One important component though
is to have a ! data sheet with a visual description of the bag code
next to the sample information for students to compare a bag in hand
with the image on the data sheet. I have been able to place about 50
samples (each about 100 mg) into a single soxhlet using this bagging
system. I hope this helps!
John Roden
Biology Department
Southern Oregon University
Ashland, OR 97520
rodenj@sou.edu
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6 Mar 2003
The suggestions about extraction sample tagging/marking have been great.
I use the Ankom "seal-a-meal" pouching, and am looking for
IDs that can be recognized from the exterior of the pouch. Either the
5B pencil or some of the coding systems would be appropriate for me,
but I was wondering if any of you have tried using prenumbered lab-mouse
ear clips? They are very small, inexpensive (about $75/1000), numbers
are stamped into the metal, a copper/nickel alloy is available, and
they would clip easily onto the end of a series of bags (given a small
amount of extra material). The Ankom pouching material is strong enough
that the clips should not tear away.
I have had student lab technicians who were dyslexic (not revealed in
the interview process) or otherwise learning disabled. With the ear
clips, the numbers could not be transposed accidentally when marking
the samples, and the clip number could be directly compared during depouching
with numbers on prelabeled storage vials. I'm also thinking that combining
the ear clips with a symbolic coding system would provide a crosscheck
for the technicians and for the PIs. Overkill? Perhaps, but some samples
cannot be replicated and samples misidentified during the generation
of stable-isotope time series can't be removed as outliers!
Thanks
Ed
--
/ / / /:/ / / / / / / / / /./ / / / / / / / / /./ / / / / / / / / /./
Dr. William E. Wright
Postdoctoral Fellow
Lamont-Doherty Earth Observatory of Columbia University
61 Route 9W
Palisades, New York, USA
10964-1000
Phone: (845) 365-8441
FAX: (845) 365-8510
/ / / /:/ / / / / / / / / /./ / / / / / / / / /./ / / / / / / / / /./
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6 Mar 2003
Hi William,
We have tried the little ear tags and they do not hold up through the
bleaching process. The only truly reliable method we have found is to
cut codes in the into the bag margins. We can't send attachments to
the list (my message with our pig ear clipping method was rejected by
the list); however, I would be happy to send it to you or anyone else
who is interested.
Renee
************
J. Renee Brooks
Western Ecology Division
U.S. EPA/NHEERL
200 SW 35th St.
Corvallis, OR 97333
(541) 754-4684 (Office)
(541) 754-4799 (FAX)
Brooks.ReneeJ@epa.gov
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