LIGHTS! CAMERA! ACTION! CUE THE MICROSCOPE!

Lights! Camera! Action! Cue the Microscope!




I’m rediscovering my childhood, well actually just bits and pieces. One part is the older television programs on DVDs. I’m semi-interested in finding famous actors in early bit parts. One series that has attracted my attention is “Have Gun, Will Travel” with the errant knight, Paladin. Played by Richard Boone, Paladin is a well educated, free thinking soldier of fortune working out of San Francisco in the 1870-1880s. Growing up in the mid 50s all the boys had business cards like Paladin. We couldn’t afford the toy gun rig, except for little Otto, who father owned the local toy store. I last saw Otto was in High School, he was still handing out those cards.


One episode which caught my attention was “Winchester Embargo” in which uneducated ranchers and town folk blame an educated Indian, opps, I should say Native American, for their sick cows.


Paladin has the soil and vegetation tested and finds high levels of molybdenum, poisoning the community’s cattle. During the dramatic climax, Paladin pulls a charred stick from the fireplace and scratches the largest Mo I have ever seen on the rancher’s adobe wall.


Good Drama. How’s the science?


Well, molybdenum was discovered by the famous Swedish chemist, Carl Wihelm Scheele in 1778. In a hundred years you could expect the discovery to complete the rounds of the educated gentry. Paladin was educated at West Point so that works.


Many Mo compounds are only sparingly soluble in water, but MoO4 reacts with water and O2 to produce very soluble compounds. Many plants use nitrogen fixing bacteria to convert N2 to NO3 ions. Modern science notes that these bacteria use Mo as part of a co-enzyme system needed to accomplish this miracle of growth.


Again score one for the show’s writers.


But is Mo dangerous? The 3 rules of poisoning are dose, dose and dose. Too much of anything can be deadly. Animal studies indicate that Mo doses at 10mg per day produce diabetes, infertility as well as detrimental effects centered on the lungs, kidneys and liver.



Again the writers score a point. But does it happen out on the range?


I got to admit, the writers have their gun sites lined up well. It seems ruminants, which include cattle, suffer from a wasting condition called hypocuprosis, or low copper levels. It’s cause? Too much Mo!!!


Match and Set.


How does Paladin determine this? Well if I was the writer, he’d pull out pre-Fritz Feigel reagent block and start running chemical test. Paladin, in a much more believable move based on past experience, takes samples to the local druggist/doctor which happen to a complete lab at hand.



But wait it gets better.


He starts with a microscope. Hurray!!!


He mounts the sample between a slide and a cover slip. Hurray!!!


He examines the sample dry. Opps.


The scope has a mirror, but our intrepid doctor doesn’t have a light. Double opps!!!


Still, not bad for a TV show in the mid 1950’s. Better than a Star Trek publication with pentavalent carbon.

Rough Going

Upper management at a previous position required me to report EDS results to two decimal places, even through the samples were rough, irregular and non-homogeneous. Despite my reluctance to provide the data, I strongly persuaded. I wanted to keep my job.

One particular upper manager had strong views on this, they bordered on religious. It seems he use to get these types of results from another microscopist, who was no longer at the company. After all the computer prints it out to two decimal places, doesn’t it?

I use to provide a disclaimer attached to my results. It made me feel that I was complying with the boss and still being true to my standards.

I recently had a chance to run an experiment on the affects of surface roughness and EDS results. I ran EDS on a textured metal sample, then polished the sample to a 1 micron polish. With all the parameters the same, I then reran EDS.

Here’s my results:

Rough surface: 12.4% lead

53.0% copper

34.6% zinc

The same sample after polishing

Polished to 1um: 4.1% lead

58.9% copper

37.0% zinc

What a difference! The lead content changes by 300%! The other elements didn’t change that much. Seems I was right (of course I knew I was) to insist on the disclaimer.

It seems that when science and politics get mixed up, science losses. CP Snow wrote a thin little booklet about science and government. I wonder what he would have written about science and business.

Microscopy amusement

Germany has opened up a new amusement park with an interesting theme: Heavy construction. According to Wired (www.wired.com) for around $150, you get to run heavy duty construction equipment for eight hours.

Oh, they have jackhammers and bobcats, but for many the thrill is running D11T’s (www.cat.com/cda/layout/cda/layout?m=237282&x=7&f=227353) and industrial backhoes. Remember building toy roads as a child? Do you stop and watch construction workers unload pipe and pour concrete? Well if so pack your bags for Germany and a fun vacation of heavy labor.

I could help wondering microscopes what I’d pay 150 bucks to play with. Assuming I could get the training first and then play, I came up with a list, and in no particular order:

Scanning Helium Ion Microscope- Good gawd… it’s so hot. Sharper images, higher depth of field, better resolution with a small spot size. Can I get what with EDS?

Scanning Transmission Electron Microscope- An oldie, but I’ve always bugged my employers to get me one. I came close at Degussa, but it was an older scope with old technology, at least 20 years old. Pass.

Scanning Tunneling Microscope- I know a couple of people working in that field and I had samples of cross sections of bear labels run at Degussa’s German Lab. I wasn’t impressed with the results I got back, but my friends tell me the results would have been better if I was sitting next to the operator.

Two–Photon Excitation Microscopy- I’ve always liked fluorescence images. They seem so extra ordinary. I started at Goodyear with a AO transmission UV fluorescence microscope. What a dog that one was! I wore safety goggles over my safety glasses and everyone in the lab got headaches within minutes of starting it up. Latter we got a second hand reflected light fluorescence scope. It was missing a lot of filters and I always thought we could have done better if we had everything.

Hotstage with pol scope and digital imaging- Clearly that’s one I’d shell out for, especially if I get the organic chemicals for fusion preps. I think Dr. McCrone popularized this in America. At least, that’s who taught me. After all these years of making fusion preps for fun, I can’t seem to forget that picric acid forms red addition compounds with most aromatic organics. McCrone has the tables to compare the melting point of the organic compound, the addition compound and the eutectics formed. This means you identify the unknown if its in the data base. It should-of-could-of replaced pre-micro sampling IR spectroscopy for aromatic compounds.

I used to take photos with Hoffman Modulation Contrast. It had some problem with artifacts, but the images were much nicer than phase contrast and had a vague 3D look to them. I’d like to revisit that.

Scanning Acoustic Microscopy appeals to me as well, but I’m a poor biologist. Still imaging the internal structure of small living biologics is very high on the cool scale. I’ve wanted to see if I could collect rubber dispersion data from it, and now I wonder what I would see in metal welds.

That my list. Comment back to me and I’ll put your list up.

Frank Karl
Microscopist

Elizabeth Becka responds!

I shot off my mouth about Ms. Becka's book "Unknown Means" and told her she could have the last word. Here it is.

Okay, here's my response. Thanks so much for this opportunity!!
First of all, I am delighted that anyone reads my books at all, much less with such attention to detail. Let me try to respond to the comments in order:

We had a color printer for the FTIR because when spectra of different samples were shown on the same graph (because analysis was not necessarily the goal here, but comparison—we don’t necessarily care what the stuff is, as long as it’s the same stuff on both victim and suspect, thus establishing a connection) the program would put each sample’s spectrum in a different color. This was quite a treat to me because at the time (10 years ago) it was the only color printer to which I had access, and came in handy for some (ahem) personal projects.

Unfortunately I have been separated from my laboratory equipment for over eight years now, so I have to write from a combination of memory and research. I confess to the error of writing silicon when I meant silicone. That was me and not the editor. Copyeditors are incredible people for catching my errors but I shouldn’t expect them to have a degree in organic chemistry as well!

I don’t know exactly why we used Permount instead of Aroclor, but we did. I liked Permount. And, yes, I would have gone on to distinguish between nylon 6 and nylon 6,6 (though probably with the FTIR or a simple solubility routine) but that would have been too much technical detail for the book. Some reviewers already think I include too much detail.

I would use dry mounts under a light microscope for quick eliminations, where fine morphology was not usually necessary. In forensic work, you see the same things over and over (usually cotton) rather than many different varieties of fiber, and again, I don’t need to identify each one. All I want to know is, could they have come from the victim’s sweater? If they are obviously different, no further examination is done.

I’m very impressed that you could identify hemp with polarized light. I used the PLM only for synthetics. I can see the confusion at the beginning of Chapter 20 because I do not specify that she is using the comparison microscope, not the PLM or the stereo (although I do mention 40x magnification), to compare the hairs and fibers. She uses the stereomicroscope only to scrape off a bit of the oily residue adhering to it.

I’m quite mystified about the Kevlar error. I’ve searched all my references and I don’t find a picture of Kevlar under a light microscope at all, and after an hour on the internet I still couldn’t find one. I don’t know if my 8 to 10 year old memory had it confused with another fiber or if I saw a picture of something somewhere that was supposed to be Kevlar and wasn’t. Since it’s now been three years since I wrote Unknown Means, I can’t remember on what I based my description.

Again, I’m thrilled that someone is reading my books with such attention! The next book should contain few if any microscopy errors, because, unfortunately, it contains very little microscopy. My character gets involved in a bank robbery/hostage crisis and is separated from her lab for most of the book—exciting, but light on the glass slides. My pen name for this one is Lisa Black and the title of the book is Takeover. It will be available anywhere books are sold next month, on August 12th. I hope you will like it, even without the FTIR analyses.

Elizabeth Becka
www.lisa-becka.com

Microscopy and Unknown Means

I’m a sucker for those fiction CSI books written by the professionals in the field. Naturally I’m drawn to Elizabeth Becka’s writing. Her forensic specially isn’t detailed on the book jacket but I suspect it’s trace evidence based on her website (www.elizabethbecka.com) and her writing. That’s important because it means microscopy. Equally interesting is that she worked for the coroner’s office in Cleveland, Ohio. That’s two connections to MSNO.

I recently picked up her book “Unknown Means”. Let’s look at the microscopy in it.

The first example that caught my eyes was not microscopy, but microsample IR analysis. I’m including this because it’s was a small sample and I have a weakness for IR spectroscopy. Evelyn, our heroine, nicely explains how organic functional groups absorbing specific radiation producing a nice color spectrum of each compound. I liked the image of a color spectrum but I fail to understand why a spectrum of non-visible light would require a color printer. I guess since I take photos graphs of very small objects I should us a tiny, tiny printer. Evelyn identifies oily stuff as silicone by the wide peak at 1000cm-1. Silicone oil does have a wide peak around 1000cm-1 (assuming it is polydimethylsilioxane), but I’d call it a double peak. Our heroine dismisses (rightly so) the common nature of silicone. My friends in IR spectroscopy claim the earth has a mono-molecular layer of silicone. It’s been my experience they maybe right. Evelyn wrongly attributes it to being the most common metal on earth. Silicon is the element and metal (Okay, metalloid) and is transparent to IR radiation. Silicone is the polymeric organic material.

This is not a good sign. A microscopist should know the difference between an element and a compound. I’ll assume the editor chopped out the information to streamline the story.

All is not lost, later she uses polarized light microscopy to identify a fiber as nylon mounted in Permount. That’s a good catch. I would have used Aroclor 166, but I’m a dinosaur. With a little more work she could have distinguished between nylon 6-6 and nylon 6, but that would only distracted from the story.

A few pages later Evelyn tells us how little information she was able to gleam from a dry mount of an unknown. This demonstrates the difference between a dry mount and the previously prepped nylon fiber in a mounting media. The refractive index of air is 1 and just about everything has a refractive index significantly larger than 1.

You would expect way too much contrast and glare, even with the sub-stage iris fully open, to see the fine morphology. Still I understand her dilemma: mount it in a solvent and the material could dissolve or react. I recently had a co-worker examined lithium oxide in water. Good bye sample, hello hydroxide and carbonate. With the context provided by the story and Evelyn’s macro description, I’d try distilled water (N=1.33). This would lower the contrast and the unknown could be recovered by wicking the water away with a corner of a Kimwipe. Still, I count this as good microscopy.

To identify an unknown fiber, Evelyn uses standards to compare known materials to her unknown and discovers the fiber is a strand of hemp. I would have used a polarized light scope, but she gets by with a stereomicroscope. More good microscopy, but later she identifies a fiber she describes as “...straight and clear. Almost like hairs without the medullas.” as Kevlar. I’ve never seen clear Kevlar. There fibers always have a yellowish tint and are never clear. The refractive indexes of Kevlar, both perpendicular and parallel to the long dimension of the fiber are very high giving the fiber enormous birefringence. The center of a Kevlar fiber, seen in cross-polarized light, has a most medulla-like look caused by micro crystals and who could miss the characteristic “X” and “Y” cracking observed in the fiber? Clearly, a microscopy miss. Sorry Evelyn.

Read the book yourself. It’s a great story which uses realistic microscopy to help solve a series of crimes, written by someone who actually does it. What could be better?

As for me, well I’m simply jealousy of both the word-smithing Ms. Becka does as well as the microscopy. PLM, SEM-EDS and IR Spectroscopy. It doesn’t get any better than these three..


PS: I’ve always wanted to spoil a story, so the killer is, ….What are you doing here? No - stop! Put that down! No! Not the eeeeeeeeeeeeeeeeeeeeeeeee