Reasonable Expectations for Cleanliness of New Materials

[rnabholz]

I have limited experience, and so would like to pose a question regarding some cover slips that I just bought.

These came nicely packaged, foil wrapped, plastic box with a foam divider that held four groups of 50 cover slips each.

Pulled my first one out, and it seems to be covered with what I would describe as a fog. I will come off with some breath and a kimwipe after a couple of tries.

I checked samples from the other groups, and they too have the "fog".

Is this normal? Should I have to expect to clean each cover slip before use?

[einman]

Do they indicate they are "clean" or "pre-cleaned"?.

It has been my experience that that is what separates some chiese made glass from those brands made in other countries. They cut corners. Dirty glass saves a lot of time and subsequently money.

What is the brand and site of manufacture?

[lorez]

I see professional quality cover slips most (99%) of the time and they have no fog, dust, or contamination, and do not need to be cleaned. In lesser circumstances I have seen what you are describing. Not knowing what you purchased it's difficult to say more.

lorez

[rnabholz]

Thanks Guys.

They are Karter Scientific. "Microscope Cover Glass 22x22mm 0.13-0.16mm"

200 Count. Cost through Amazon was about $5. http://amzn.com/B005Z4RWKM

Maybe I am shopping at the bottom of the quality ladder? If so, I would appreciate any advice on a quality alternative.

Thanks

Rod

[lorez]

You may be able to find a source from your local veterinarian. They buy from industry specific vendors, but not in the huge quantities of the hospitals.

It could be that your vet will sell you a box, or order some for you.

lorez

[Crater Eddie]

I have a box of those same cover slips, I have to polish every one before using it. Very annoying. I recently got a box of Globe Scientific slides, they are very clean.
CE

[gekko]

I've heard of this problem before. According to one source, the white stuff is the result of a chemical reaction mediated by moisture (at least that is what I understood from a very quick look at his patent, scroll about 1/3 of the way down):
http://www.google.com/patents/US4681218

For what it's worth, I buy my slides and cover glasses from Ted Pella and I never had this problem. Their prices are good (e.g. $7.30 for a 1 oz box of 22x40 mm cover glasses), but I reuse both slides and cover glasses and only replace them when damaged, scratched, broken, or lost . Shipping, though, may be relatively expensive if you only want to buy one box. There are other equally good vendors of scientific supplies (e.g., Fisher Scientific, VWR, etc., but I don't know which ones sell to individuals).

[zzffnn]

Zeiss sells to individuals and offers some #1.5 high performance (D=0.17 mm +/- 0.005 mm) cover slips:

https://www.micro-shop.zeiss.com/?s=225 ... 0-9020-000

Their smaller 18*18 mm2 version is not expensive per piece (you have to buy 1000 pieces, for around $50 shipped, though). Their bigger 22*22 mm2 version is a bit expensive at $37 shipped per 200 pieces.

I bought the smaller version and just checked their cleanliness from a new unopened box. They don't look foggy but they are NOT perfectly clean under oblique light. If you image a lot in darkfield, they won't be clean enough. But I heard most cover slips won't be clean enough for darkfield imaging, unless you wash them with strong acids in a lab, like some professionals do. I have not done that myself, but there should be cover cleaning protocols online if you google.

For non-darkfield use, such as oblique, dust won't show up that much and I sometimes use cheap Chinese cover slips (for low NA they are just fine).

It is not necessary to use high performance #1.5, unless you have high dry NA 0.85-0.95 objectives. And if you have a good micrometer, you can buy cheaper #1.5 covers and hand select thickness, when needed.

[mrsonchus]

Hi, in my experience of many different shapes & sizes of cover-slips this is, at my end of the spectrum (the cheap end!) completely normal and to be expected. I think it's just a case of cheaper being inferior but almost perfectly usable.
I always used to clean them with OH, tried Histoclear (wax solvent/clearing agent) which was uselessly smeary and settled on OH and quite a lot of fussing to get them clean.
Then a lucky and chance discovery helped me out - I started using acid-OH for certain staining techniques in the form of my already in-use FAA (fixative). One time a trace of this was left on a section before I cover-slipped and mounted in the usual manner - but I noticed and area of the slide that was unusually (at that time anyway - not any more ) clear and clean - the FAA traces had perfectly cleaned the slide!
A few tests later and I had my now std method for cleaning cover-slips before use - forceps - pick up cover-slip and dip into acid-OH (acetic acid - just like my Mother always said, "vinegar is great for cleaning glass"!) wipe with tissue (kitchen-roll) then dip and wipe in pure OH - place cover-slip onto specimen and hey-presto! Nowadays I run-off about a dozen cover-slips of each shape/size and use them from 'the clean box'. They come-up perfectly clean & clear every time now.
I'm certain that premium cover-slips will not have this problem - but there are clearly cheapo-Chines versions masquerading as the 'real-thing' out there, foil wrapping included - had them myself, same 'fogging' exists...
Thing is, once cleaned they seem OK, but for high-power or critical work or just as a means of getting the best from your mounts it will probably be worth paying considerably more than the paltry £3 per 100 that I currently pay!

I'm personally going to move to a far better grade in the near future as my slides improve to the point of being worth keeping and adding to my just-started 'proper' collection of permanently-mounted slides....
To my mind and limited finances paying say £20 per 100 for perfectly clean, flat, thickness-guaranteed lab-grade cover-slips for permanent mounts is fair enough.. as long as the quality is indisputably and demonstrably of a high standard.

Same goes for slides I find, I now buy Leica positively-charged slides and find them to be superb - no cleaning needed but more impressively, sections once dried may be processed (de-waxed etc and stained then mounted) after only about 24-36hrs! Sections stick to these slides as though they've been stuck-on with 'superglue'!

Used to clean used slides with Histoclear (as I reclaim a lot of slides that have wax-sections from floating-out that never get to be further processed), then clean and leave them in OH until use - I then fount that after Histoclear and an OH 'dip & wipe' soapy water and a hot-water rinse dried with a soft and perfectly clean cloth does by far the best job, simply back into a clean and dust-free box and they're literally as 'good as new'! No more storing them wet in OH for me!

That's where I am with them, really a process of 'live and learn' for me.

[Dale]

I got mine from a big hospital that had its own stat-lab. I brought them a box of chocolates and got
500 slides.
Dale

[gekko]

It is not necessary to use high performance #1.5, unless you have high dry NA 0.85-0.95 objectives. And if you have a good micrometer, you can buy cheaper #1.5 covers and hand select thickness, when needed.

The difficulty I see is that with the kind of microscopy some of us do, it is not easy (or possible) for the object of interest to be virtually in contact with the lower surface of the cover glass (which would be required for those high NA objectives with 0.17 mm cover glasses) in which case such cover glasses would be rather too thick by an indeterminate amount. Based on that assumption, I use #1 cover glasses (0.13 - 0.15 mm) with the (perhaps unwarranted) hope that the layer of water or other mountant between the object and cover glass will compensate sfficiently for the "incorrect" thickness of the cover glass. I would imagine (but I don't know that for sure) that in general modern high quality objectives that are super sensitive to cover glass thickness would be equipped with correction collars.

For making permanent slides, I agree that it would be worth measuring the cover glass thickness and choose ones that are very close to (but not exceeding) 0.17 mm, but in addition, avoid having mountant between the object and the cover glass.

[mrsonchus]

...............................................
For making permanent slides, I agree that it would be worth measuring the cover glass thickness and choose ones that are very close to (but not exceeding) 0.17 mm, but in addition, avoid having mountant between the object and the cover glass.

That makes perfect sense to me Gekko, and the practical solution of measuring and 'sorting' cover-slips for permanent-mounting is also a good one certainly. It's an area I definitely plan to address in the new year also...

[zzffnn]

Rod,

Regarding cover slip clearness, I did a direct comparison, between my Zeiss cover and Première (Chinese) cover. The Chinese is visible more dirty and can be called foggy if you are pickky. The Zeiss is not perfectly spotless but looks much cleaner, when view the same way, than the Chinese.

gekko,

I agree with you in that cover thickness to be used depends on sample preparation and having cover correction is key.

From my limited experience and with my own sample preparation methods, about 1/3 of the time I can obtain very thin wet mount (2/3 of the time I got tiny sand particles that raise up the cover).

I do have a LOMO NA 0.95 40x with correction collar (which is a copy of old Zeiss Jena) coming to me from Russia and will comment on collar setting when I receive it.

[charlie g]

Hi, I'm in NY/NJ area..and over the years I've never been burnt by fogged cover slips or slides...even the cheapo firms.

I would contact the seller..ask if you need return all these fogged slips...vrs they just assure you they can send to you un-fogged slips'?

Don't prejudge the vendor..first see if they respond to the above contact querry. Even from late 1940's stamped:"occupied Japan"...I purchased quite a lot of rectangular cover slips...none fogged. No way should you be expected to waste effort 'unfogging delicate slips of glass'.

I still intend to purchase those super calibrated Zeiss coverslips a lot of kind forum microscopists have shared the link for over the years...I want to use these with my Nikon Plan 100X dry 0.90 correction collar objective...and with my Nikon PlanApo 60X 0.95 with correction collar objective. I still haven't made the purchase...but it will be an education for me to see funtion of my correction collars, my ability to compare with my: "Globe Scientific", Paramus, NJ clinical grade low cost quality slides, and quality coverslips ( I just coined the term: clinical grade...my bad).

Please give contacting that vendor a try. Two years ago when one of the eight microscope bulbs I purchased from a Long Island,NY firm had a broken filament...the gent on the phone said: 'keep it, we will send you another.'.

Please don't go sour (just yet) on those fogged slips...go for contacting the firm...even in China I have contacted a rep once last year. charlie guevara

[Crater Eddie]

I do have a LOMO NA 0.95 40x with correction collar (which is a copy of old Zeiss Jena) coming to me from Russia and will comment on collar setting when I receive it.

Not to hijack the thread, but if that 40x APO is clear, you are going to like it!
CE

[rnabholz]

Thank you everyone for all the great information, discussion and perspectives.

It was because I do find myself using Dark Field more often that this became an issue. I noticed a background brightness that was being caused by the dirty coverslips.

I do wash and reuse my slides, and don't find that too much bother, but those tiny fragile coverslips are a real pain. Believe me, I try to save money on my hobbies whenever i can, I have too many hobbies not to, but after washing the last batch of coverslips, and finding the ones that I didn't break were still dirty, I decided life was too short to let something about my new hobby become a pain. Especially when I might use less than a quarter dollar's worth in each session. Pretty cheap entertainment.

So from that perspective, I have no interest in cleaning 400 brand new coverslips. I will contact the vendor and see how they want to handle it, but will be trying to find cover slips that are clean out of the box.

Thanks again.

Rod

[billbillt]

I have cheap Chinese "Sail Brand" slides and cover slips here, and they are almost spotless right out of the box... I don't see where all of this contamination with new slides could be coming from.. Strange..

BillT

[gekko]

Thank you everyone for all the great information, discussion and perspectives.

It was because I do find myself using Dark Field more often that this became an issue. I noticed a background brightness that was being caused by the dirty coverslips.

I do wash and reuse my slides, and don't find that too much bother, but those tiny fragile coverslips are a real pain. Believe me, I try to save money on my hobbies whenever i can, I have too many hobbies not to, but after washing the last batch of coverslips, and finding the ones that I didn't break were still dirty, I decided life was too short to let something about my new hobby become a pain. Especially when I might use less than a quarter dollar's worth in each session. Pretty cheap entertainment.

So from that perspective, I have no interest in cleaning 400 brand new coverslips. I will contact the vendor and see how they want to handle it, but will be trying to find cover slips that are clean out of the box.

Thanks again.

Rod

For what it's worth (I admit, probably not much ) The new slides and cover glasses I use are quite clean out of the box. Still. upon first use, I spray them with isopropyl alcohol and wipe them dry with a clean microfiber cloth. After use, I rinse them under hot, running water, then spray them with alcohol and wipe them dry with the microfiber cloth before using them again. But since I clean one slide and one cover glass, it only takes seconds to do. Anyway, I'm not implying that this is the best (or even a good) way to do things-- it is just my way .

[75RR]

Warning - Hijacking thread! (Hope you do not mind too much) :)

I do have a LOMO NA 0.95 40x with correction collar (which is a copy of old Zeiss Jena) coming to me from Russia and will comment on collar setting when I receive it.

Most interesting! Will that work with a Zeiss KPL eyepiece? What is the working distance?

[rnabholz]

gekko wrote [/quote]For what it's worth (I admit, probably not much ) The new slides and cover glasses I use are quite clean out of the box. Still. upon first use, I spray them with isopropyl alcohol and wipe them dry with a clean microfiber cloth. After use, I rinse them under hot, running water, then spray them with alcohol and wipe them dry with the microfiber cloth before using them again. But since I clean one slide and one cover glass, it only takes seconds to do. Anyway, I'm not implying that this is the best (or even a good) way to do things-- it is just my way .[/quote]

Hey Gekko,

Your approach makes sense, I am a bit more slothful....

Between Work and Kids and other obligations, I always seem to find myself rushed for time, so I tend to spend the available time at the eyepiece and leave the clean up to the weekend day - often after letting a number of weekends pass. So when I finally get around to "doing the dishes", it is not uncommon for me to have 30 to 50 dual window masked slides to wash and 60 to 100 coverslips.

I should clean as I go, but I would rather spend the time observing, shooting and sharing, even if it costs me a little bit more. I think I can say that it is definitely not the best way, but I guess I will just add that to the list of my idiosyncrasies.

Thanks

Rod

[rnabholz]

Warning - Hijacking thread! (Hope you do not mind too much)

I do have a LOMO NA 0.95 40x with correction collar (which is a copy of old Zeiss Jena) coming to me from Russia and will comment on collar setting when I receive it.

Most interesting! Will that work with a Zeiss KPL eyepiece? What is the working distance?

No worries 75.

[kit1980]

A few tests later and I had my now std method for cleaning cover-slips before use - forceps - pick up cover-slip and dip into acid-OH (acetic acid - just like my Mother always said, "vinegar is great for cleaning glass"!)

Hi mrsonchus, what concentration of acetic acid do you use for cover slips cleaning?
I've bought some 99.85+% stuff and it feels dangerous to use or even store...

[mrsonchus]

A few tests later and I had my now std method for cleaning cover-slips before use - forceps - pick up cover-slip and dip into acid-OH (acetic acid - just like my Mother always said, "vinegar is great for cleaning glass"!)

Hi mrsonchus, what concentration of acetic acid do you use for cover slips cleaning?
I've bought some 99.85+% stuff and it feels dangerous to use or even store...

Hi kit', don't worry about it being too dangerous - it's smell and the fact that (if it's 'glacial') it freezes at about 17 deg C may also be a little disconcerting when one receives the bottle in the post and it's frozen solid at room-ish temp! A touch surprising and a little scary at first!

Anyway - my advice, which I do follow, is to have an antidote to anything dangerous in the lab (very) near-by. Always have literally within arm's reach a wad of towels or cloth and a large bottle (wide-mouthed) of tap water - ready for the usual 'swab-it then soak-it' response that works so well in the home-lab.

So, concentration, I use 0.2% and/or 1% for staining and cover-slip dipping - but find these days that the most effective method of all is also happily the easiest...
I simply dip the slips (I'm referring to new-out-if-the-wrapping slips here - in my mounting I don't re-use them) into water (DI or tap) and wipe them dry and clean with a soft and freshly-washed (i.e. totally unused) cotton 'tea-towel' as they're called in the UK.

I find OH leaves residue, as do apparently pristine tissues (I believe Rodney mentioned this recently also) - the clean water & soft cloth (again I find 'microfiber' to be pretty poor also) always wins and is clean, free and fast!

But, to use acetic-acid I'd say anywhere within the 0.2 - 1.0% range is fine and good for re-use of coverslips ala live-examination - and of course simple 'Fairy-Liquid' (a UK name for dish-washing liquid - hand not dishwasher that is) in warm water with a clean water rinse will work 99.9% of the time - if it doesn't I bin the coverslip.

Good luck - try the water - I tried it on it's own and hey-presto!

[kit1980]

Thank you, mrsonchus!
I want to try acetic acid because I have cheap "foggy" cover slips, and also I reuse them.
Now I have a lifetime amount of vinegar stuff - 950ml of almost 100% acid

[mrsonchus]

Thank you, mrsonchus!
I want to try acetic acid because I have cheap "foggy" cover slips, and also I reuse them.
Now I have a lifetime amount of vinegar stuff - 950ml of almost 100% acid

I use the same - no matter which ones I try they're always as you say 'foggy' out of the wrapper! It's really frustrating but I will soon take the trouble to find a source of 'proper' lab-quality coverslips - for permanent mounts it will make sense to spend the extra per slip I think....

[apochronaut]

The problem you are describing I have found with old glass, that has been sitting around. It does seem to be a slow chemical reaction . I've not had a problem with glass that I can verify as not having sat around, possibly in warm humid conditions before being shipped.

[mrsonchus]

The problem you are describing I have found with old glass, that has been sitting around. It does seem to be a slow chemical reaction . I've not had a problem with glass that I can verify as not having sat around, possibly in warm humid conditions before being shipped.

Yes, it's almost as if they appear to be etched in some way - I suspect you're right apo'- they really do have the appearance of 'not being fresh' for want of a better term....

[hkv]

I use VWR slides and slips. I have found these very clean, or at least I have not noticed any dirt, dust or fog. I never clean them before use. I always through away cover slips and use a new every time. I normally reuse the slides unless they are too sticky and time is short...

[Radazz]

I've been using Boreal cover slips, and haven't noticed this problem.

I tried cleaning cover slips, but I can barely handle them without breaking them, so I stopped reusing them altogether. Part of the expense of the hobby, and minuscule compared to my initial equipment investment.

Perhaps, I'm also a lazy old man.

Jim

[mrsonchus]

I use VWR slides and slips. I have found these very clean, or at least I have not noticed any dirt, dust or fog. I never clean them before use. I always through away cover slips and use a new every time. I normally reuse the slides unless they are too sticky and time is short...

Hi, I've just registered with VWR with an intention to buy cover-slips from them, I'm unsure though if as a private individual my registration will go through OK...
I may have trouble as a private buyer but I thought I'd give it a try anyway as the thought of being able to use high quality cover-slips that are actually clean has been tormenting me for about a year now!

I'll order some ASAP if all goes well.