1/22/97

The question of the day is:

What is the best way to store SEM samples (those already on stubs and

sputter coated)?

Thanks in advance (I just figured out that's what TIA means).

Paula Sicurello

UC Berkeley

ELectron Microscope Lab

We store our specimens in a specimen storage cabinet that we bought from

Agar Aids. We keep dessicant in it and we change it periodically.

Manuela Palatsides

manuelap@petermac.unimelb.edu.au

of Kevin Cronyn (Hitachi Sales) I bought plastic hinged-lid boxes (about 4"

x9") from one of the EM suppliers and cut pieces of plexiglass to fit in

the bottom. I then drilled and threaded 32 holes in the plexiglass and ran

short (~1/2") bolts up through the holes. The thread size is the same as

for the Hitachi stubs so you just screw the stubs down on the bolts and set

the whole unit in the plastic box. I put one longer (~1") screw in the

middle to act as a handle for getting the plexiglass out of the box. I

seem to recall that it came to about $20 in supplies for each box as well

as two hours of drilling and tapping a bunch of little holes. I can send

more details if you are interested.

For short-term student use I give them petri plates with

double-sided tape in the bottom. Stubs are placed on the tape and stick

pretty well. You can get up to 10 or so stubs in one standard Petri dish.

YWIA

Bob

Robert R. Wise

Plant Physiologist and Director, UWO Electron Microscope Facility

Department of Biology

University of Wisconsin Oshkosh

Oshkosh, WI 54901

(414) 424-3404 tel

(414) 424-1101 fax

wise@uwosh.edu

Pella (clear plastic boxes) and place in either a glass desiccator or

zip-lock bag with desiccant. The boxes offer the advantages: numerically

labeled for specimen ID, hold the specimens tightly so that they will not

spill out if inverted or tipped.

A cheaper alternative is to take some 1/2" plexiglass and drill a series of

holes that will allow the stubs to fit. A dab of sticky tab will adhere the

stub to the plexiglass. If one attaches small legs, the plexiglass panels

may be stacked on top of each other. This may then be desiccated.

Cheapest yet, someone (EMS or Pella or SPI) makes some paper boxes (like

"pill boxes" of olden days) that you can write on.

Good luck.

John J. Bozzola, Ph.D., Director

Center for Electron Microscopy

Southern Illinois University

Carbondale, IL 62901-4402

U.S.A.

Phone: 618-453-3730

Fax: 618-453-2665

Email: bozzola@siu.edu

Web: http://www.siu.edu/departments/shops/cem.html

Here at the museum our SEM samples are frequently from registered

specimens from the collections and are often the type specimens of new

species. Our stubs are, therefore, stored "in perpetuity" like the

rest of the collections. Years ago I asked some questions regarding

conditions for permanent storage but there wasn't much info

forthcoming apart from the usual methods. For what it's worth, here

are some of my observations on stubs 15-20 years old.

The oldest stubs in our museum have been stored in large (~300mm

diam.) glass petri dishes, stuck down on double-sided sticky tape.

These petri dishes are kept in stacks of three in glass dessicators

(with silica gel) which are sealed with petroleum jelly. Most of them

are still good for the SEM - the bad ones are attributable to poor

preparation (and subsequent degradation) rather than storage

conditions. Others have used disposable plastic 110mm dishes,

however, this is not so space-efficient.

I guess that low humidity and constant temperature are the important

factors. I've thought (comments please) that it might be worth

replacing the air with an inert gas as well.

We then looked at perspex cabinets with shelves. None were to our

liking (usually too few shelves and too expensive) so we designed our

own for a person who wanted to produce them for his supply shop.

Originally we had planned for a stackable perspex cabinet (340mm wide,

280mm deep, 260mm high) with O-ring in the door, full-length side

hinge, roller clips to provide pressure on the O-ring, gas exchange

taps (pump inert gas in through one and air out the other) and 10

shelves which held 1,760 stubs. Unfortunately, supply of parts and

costs for materials and labour, on what was only ever going to be a

small run, meant considerable changes and the result can only be

called a very efficient dust cabinet (still stores 1,760 stubs!).

With monthly changes of silica gel it works as a dessicator.

Any supply houses interested in bringing this design to fruition?

Geoff Avern

Microscopy Laboratories

Australian Museum

Sydney, Australia

geoffa@amsg.austmus.gov.au

because that's what I just told my new SEM class and what I tell everyone

else. Our main concern here in Hawaii is humidity, and I insist that all

samples be held over dessicant for some time before going into our field

emission SEM. Most of us put our pin-style stubs in commercially

available boxes and find that, once sputter coated, they will then store

*indefinitely* over dissicant. The identification and procurement of

suitable jars is a serious subject here, especially now that many brands

of peanut butter are now available only in plastic jars with a

thin, styrofoam-like seal, driving us to other snacks that come in jars

with the requisite rubber ring in the lid. Jellies and pickles and other

fluid items frequently come in jars with wide mouths, allowing room for

insertion of fingers to retrieve sample storage boxes. Mayonnaise jars,

alas, do not have the rubber ring in the lid. Canning jars are popular

among our customers with active grants to pay for them. Be warned,

however, against using jars which may have strong residual scents; kim

chee jars are a no-no. Avoid, too, jars which have contained spaghetti

sauce or other tomato-based products as some strange mungy stuff likes to

grow in them even after being subjected to multiple runs in the

dishwasher. I have not attempted to autoclave them.

Tupperware brand storage boxes work well for a fair period of time; other

brands do not seal well enough to keep indicator dessicant from

indicating. My Tupperware lady thinks I'm nuts. She may be right.

Jars of all shapes and sizes full of stub boxes pile up in our facility

until I run down their long-lost owners or shove them in their campus mail

boxes. I can't help you with that problem!

If the question is, rather, how does one keep the stubs upright and

undamaged if they are the type that does not fit snugly in comercially

available storage boxes, or one can't afford said boxes, I am of less

help. I like to encourage my customers and students to be creative (I

have an interesting collection of boxes designed to hold glass knives, for

example). I have not yet tried to see if 1/8" pin-type stubs fit in the

holes of pipettor tip boxes. Hitachi screw-on stubs are such a pain that

I made an adaptor to hold pin-type stubs before I took delivery of the

'scope. I remember that you have an ISI DS-130, but I don't remember the

stub type.

Last week I looked at some stubs of unknown origin that had been knocking

around in a petri dish in a desk drawer for at *least* 12 years. I put

them over silica gel for a day and popped them into the 'scope without

further coating and found some wonderful cultured cells that looked just

great!

I'd rather be in the lab than home with this cold. (It's raining in

Hawaii.)

Tina

MicroAngelo soon admitting gender and changing to MicroAngela

http://www.pbrc.hawaii.edu/bemf/microangelo

Tina (Weatherby) Carvalho tina@pbrc.hawaii.edu

Biological Electron Microscope Facility (808) 956-6251

University of Hawaii at Manoa http://www.pbrc.hawaii.edu/bemf

The vacuum is not very good (rough pumping) but sufficient to prevent damages

of the sputtered layer, water vapor uptake and/or oxidation of the samples.

As our (Philips) stubs have a pin underneath, we have drilled holes in the

cabinet's shelves. This way the samples are fairly secured when you move the

shelves. This storage is meant for samples we might want/need to put back in

the microscope. Once they are no longer current, we have a large drawer with

a rubber foam (neoprene) layer in which we've drilled holes too so that the

pin stubs will fit. It works very well and if you reference your shelves and

drawers, you might even be able to actually find old samples back: -).

Have a nice day

J.-M. Boichat e-mail: jean-marc.boechat@chma.mhs.ciba.com

EM LABS

Ciba Research Center phone:++41264356979 fax:++41264356907

P.O. Box 64

1723 Marly 1

described, depending on the state of our budget at the time. For extended

storage of samples that you really don't expect to ever look at again but

someone insists that you archive, we have taken to using the commercial

storage box placed in a seal-a-meal bag with some charged silica gel. The

bag is evacuated and sealed for storage on a high shelf in the lab. The

indicator in the silica gel shows that it is still dry after three years.

G.W. Erdos, Ph.D. Phone: 352-392-1295

Scientific Director,

ICBR Electron Microscopy Core Lab

218 Carr Hall Fax: 352-846-0251

University of Florida E-mail: gwe@biotech.ufl.edu

Gainesville, FL 32611 http://www.biotech.ufl.edu/~emcl/

Home of the #1 Gators

You've probably heard from every vendor and his or her dog by now, and we

also sell a variety of SEM specimen storage boxes, but, in my opinion, the

*best* storage method is a good desiccator cabinet with shelving having

holes to accomodate the specific specimen mounts you are using. At least

two of the EM supply companies sell such systems, Energy Beam Sciences being

one of them. My second choice, for standard "pin-type" specimen mounts,

would be this lovely wooden mount storage box, made in the U.K., and sold by

at least the same two vendors.

Best regards,

Steven E. Slap, Vice-President

Energy Beam Sciences, Inc.

Adding Brilliance To Your Vision

ebs@ebsciences.com

http://www.ebsciences.com/

I agree with Geoff (and several others): humidty is very important.

However, I'd rate protection against mechanical shock 2nd, then

temperature, etc. Make sure the stubs are firmly mounted, sticky tape is

only for temporary storage or for when you can be assured that specimens

won't be moved. I've used specimens that I've shipped in a VW bug across

country and ones shipped from Antarctica, and sticky tape would *not* have

done the job. Stubs firmly mounted in commercial or specially made stub

holders do OK. Also, make sure the specimens are firmly mounted on the

stub--it can take only a small jar to knock specimens off the stub or

de-orient them. Given the rough handling of specimens by many people,

long-distance shipping isn't needed to lose samples, just a trip across the

lab or campus.

For medium to long term storage, vacuum (10-3) or *dry, oil-free*

inert gas (N2 or Ar) is good; for archival storage, I'd exchange the air

with N2 or Ar and then pump down. O2 can be a long term problem, but I

wonder more about the general crud in the lab air.

Phil

Philip Oshel

Station A

PO Box 5037

Champaign, IL 61825-5037

(217)244-3145 days

(217)355-3145 evenings

oshel@ux1.cso.uiuc.edu

is super clean. We're plumbed up to it for air tables, sample

blow off, and we bleed it slowly into those big plastic boxes

with the foam door seals, bolted to the wall. This is convenient,

ultra-dry, and close enough to vibration free. We just use any

sample box designed for 1/8" stud sample mounts.

Dave King

deking@vnet.ibm.com

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