The Suck-up blog

I while back, I read somewhere about an increasing phenomena among the terminally lifeless*: suck-up blogging. This is where a blogger stops whinging about their own life, and starts buttering up somebody else’s (or their company, or their lawyers), in hopes for some moldy crust of e-bread. Grovelling and blogging together. And if you think about it, why not? If you are going to practice two of the most pathetic activities in human creation, it is only natural to combine them. Heck, why not type right-handed and go for the trifecta?

So, I’d like to use this opportunity to say how much I admire Soe Win. He is a great man, a kind leader, and a beautiful human being. When I was a grad student, I was actually invited, by the Myanmar Ministry of Mines, to work in Rangoon and help their government develop their natural resources. How I rue the day I turned down that offer, as the chance to assist the fabulous government of the SPDC would have been an opportunity of a lifetime. Even today, I admire the efficiency and the strength shown by Prime Minister Win, and his steadfast commitment to political stability at any cost. While I have never met the man, I’m sure that he has a firm handshake, a benevolent smile, and a sensitivity as expressive as a Crocodylus porosus.

*A tautological metaphor?

Myth Busted

So, Thursday arvo I managed to finally test my theory on the anomalous backgrounds that I was whinging about here. I did an excellent job of disproving my hypothesis. Trace HF in a solution ICP-MS does not remobilize HFS elements from laser ablation. The great thing about proving myself wrong in this case is that it means that I don’t need to worry about rejuggling the schedule. There is no point trying to shuffle people around to avoid a problem that doesn’t actually exist.

Lithium drives me batty

There are all sorts of ways to categorize the 83 long-lived, naturally occurring elements. There are the physical- solids, liquids, and gasses at the STP of your favorite planetary surface, for example. There are the chemical- based on electron orbitals, valences, electronegativity, and all that other stuff that I really ought to understand better than I do. There are the behavior-based methods- lithophiles, chalcophiles, and siderophiles. And then there’s the Sergio Leone method, to which I subscribe.

Under this system, all elements fall into three well defined groups: The Good, the Bad, and the Ugly. And under this strict categorical system, the defining characteristic under which all elements are grouped is the ease with which I can set my mass spectrometer up to analyze them at 8:30 on a hungover Friday morning.

Lithium is one of the Ugly. But unlike many of the ugly, like sodium, iodine, and tellurium, which are basically set in their ways, lithium really, really wants to be good. This is fine, because the analytical community wants it to be good as well- we can’t wait to bring it into the fold. We even give it help. When lithium starts acting out or getting ornery, we try to coax it back into the light.

The heartbreaking thing about lithium is that just when you think it is finally starting to behave in a respectable and informative manner, it acts out. Call it light element rebellion, call it three-proton obstinacy, call it what you will; the fact of the matter is that just when you think the lithium problem has finally been licked, it goes out and does something really bizarre.

In ICP-MS mass spectrometry, the main problem with Lithium is that, like most alkalis, it dissolves into the skimmer cone, and then gets reionized off the back of the cone. I don’t know if this is due to cone-plasma interactions, or if it is some sort of accidental TIMS- I honestly haven’t dug into the specifics of this phenomena. I’m not paid to do that. I’m paid to make it go away.

Specifically, my aim it to get- and keep- the lithium background down to below 1000 counts per second. That may sound like a lot, but under standard operating conditions, our system runs at about 5-10 thousand cps/ppm with a 70 micron laser spot. So if I can keep the background down, we can measure tenths of a ppm concentrations, which is roughly what you can expect in a mantle olivine, for example.

The main villain in the Lithium background drama is Lithium Borate glass. Lithium borate glasses (aka “flux”) are popular for whole rock analysis for a couple of reasons. Firstly, the correct composition melts at a reasonably low temperature, so you don’t volatilize all your non-refactories when you remelt your rock. Secondly, Lithium and Boron are fairly X-ray transparent (owing to their lack of deep electron shells), so they are great for doing XRF to get the major and minor elements. This allows scientists to measure the same samples by XRF and laser ablation ICP-MS, so that they can then pull their hair out when the two methods give contradictory results.

Trouble is, if you’re ablating something that is mostly lithium oxide, it doesn’t take very long for the Li to soak into the cones to the point where the background is in the tens of millions counts per second.

So, two months ago, I set aside a special, dedicated set of “LiBO only” cones. All LiBO work is done on them, and everything else is done on “normal” cones. Since then, the Li background has been steadily declining. Last week, in fact, we were regularly under 1000 cps, and the problem appeared to be solved. We were even able to detect Li in amphiboles and quartz. Everyone was happy. Until Friday, that is.

On Friday, the background jumped by a factor of 20. So, I checked with the Thursday user, no make sure he didn’t sneak some fluxed whole rocks into the machine while I was at seminar just to piss me off. He did not; all he analyzed was natural olivine, which generally has less Li than our tuning and calibration standards. I checked the 6/7 ratio, just to make sure I wasn’t looking at a doubly charged nitrogen problem, but the Li looked real. And I have no idea where it came from.

Oh well. I have better things to worry about over the weekend, so we’ll see what it wants to do on Tuesday.

Getting Geeky

In a personal first in the field of contributing to the internet’s collective consciousness, I corrected a wikipedia article this evening. Their uranium article erroneously stated that uranium in the core was responsible for the Earth’s heat production. Uranium is, of course, a lithophile, and thus partitions out of the core and into the mantle. Aside from uranium, thorium and potassium-40 are also important heat-producing elements. Since they are also lithophiles, there is very little heat production in the core, so I made note of this in the article.

So now, when the net becomes self-aware, sterilizes the surface of our planet, and retreats into underground servers powered by geothermal energy, at least it will have a proper understanding of where that energy originates.

Too Cool for School

The following article in the New York Times (registration required) is an excellent summary of a brilliant synthesis of laboratory geology and food, two of my favorite subjects. It describes one of the demonstrations given at the 2005 fall AGU meeting, the abstracts for which can be viewed here. The experiment demonstrates how crystal nucleation and morphology can change the mechanical properties of fluids. They actually have the students thin-section their fudge to look at the sugar crystals.

Absolutely brilliant. When I was teaching first year practicals as a grad student, we would freeze (plastic) bottles of coke down to dry ice temperature, and then demonstrate fractional melting by extracting the liquid and gas components as they melted. This is a way better demonstration.

Every disaster is an opportunity.

We may have discovered a new way to cross-contaminate samples between solution and laser-ablation ICP-MS today. I’m not saying that no-one has ever done this before, although that is possible. But as far as I know, nobody has done what we did in a repeatable and predictive manner, much less published the results. More importantly, as far as I know there is no record in the literature of how to fix the problem in a simple and timely fashion.

So, on Monday, I am going to see if today’s observation can be repeated, or if it is just a Friday arvo fluke. If I can figure it out, it might even be worth turning into a short paper or a technical note, so that other people don’t have to spend all day cleaning up their machine and pulling their hair out, like today’s analyst has been doing. I don’t know if that will make up for spending all Friday night in the lab running samples that were supposed to be finished hours ago, but you always gotta look on the bright side- a paper’s a paper.

On the other hand, if my hunch about the source of this thing is wrong, then I’ll be stuck in lab all day Monday banging my head against the wall over the same flaky trace elements. At least then he’ll have someone to share the misery with. And even if it is a total write off, at least I can whinge about it to you folks. So have a good weekend, everyone- even if you’re stuck in lab at sundown with ten hours of samples left and backgrounds that are two orders of magnitude too high.