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Week of 18 August 2008


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Monday, 18 August 2008
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08:22 - This weekend, I had an idea that could revolutionize home science and science education, not to mention a lot of other endeavors.

What we need are inexpensive, and I mean really inexpensive, laboratory instruments. Things like gas chromatographs, high-performance liquid chromatographs, atomic-absorption chromatographs, visible/UV/IR spectophotometers, mass spectrometers, Fourier-transform infrared spectrometers, nuclear magnetic resonance spectrometers, and so on.

I don't see any reason why basic versions of most such instruments couldn't be mass-produced and sold for the price of a decent microscope, or less. They wouldn't have to have any smarts. PCs are ubiquitous, so the instruments would need only USB ports to connect to a lab PC. The guts of most of these instruments are surprisingly simple. Things like glass, plastic, and stainless steel tubing, vacuum pumps, diffraction gratings and slits, photodetectors and CCDs, lamps and LEDs, heating elements, and so on.

Here, for example, is a visible light spectrometer that sells for $1,600. If it were mass-produced, there's no reason it couldn't sell for $100 or less. Other types of spectrographs and chromatographs could also be produced to sell for very low prices. Sure, the resolution, precision, sensitivity, and range of such inexpensive instruments would be lower than that of a $25,000 instrument, let alone a $250,000 instrument, but they'd be no less useful for that.

So who'd buy a $100 visible/UV/IR spectrometer or a $200 gas chromatograph? I would, for a start, and so would a lot of hobbyists. Not to mention middle-schools, high-schools, and even universities. For that matter, a lot of corporate and government labs would probably buy such instruments.

When it comes to instrumental analysis equipment, we're still back in the dark ages. I'm old enough to remember when the mainframe was the holy-of-holies, and we acolytes stood attendance on it, waiting patiently in line with our card decks for the few seconds of machine time we needed. Let me tell you, compiling and debugging a program back in those days wasn't much fun. And I remember in college and graduate school waiting for a time slot on an IR or NMR instrument. I doubt things have changed much. In many cases, the instrument is still the bottleneck.

People queue up for time on $250,000 instruments, or even $25,000 instruments. In many labs, time on those instruments is booked for days, weeks, sometimes even months in advance. That's one reason forensics work is so notoriously slow. The staff aren't the bottleneck. They do what they can in a timely manner. But they often have to wait for free time slots on expensive GC or AA or MS instruments.

That's why wet-chemistry presumptive tests are still so commonly used in forensics labs. A positive presumptive test doesn't prove anything in a legal sense--it can't be used for court testimony--but what it does do is let the forensics scientists use the expensive equipment only for definitive confirmatory tests that are admissable in court.

But what if inexpensive versions of these expensive instruments were available? It'd be the equivalent of putting a PC on everyone's desk. But instead, you'd put a $200 GC or whatever on the lab bench of anyone who needed one regularly, or even once a week. The lower sensitivity, resolution, precision, and range of the inexpensive instrument would often suffice. Better is often the enemy of good enough. If I'm testing for gunshot residue or the presence of an accelerant, all I care about is whether it's present or absent and, if present, some idea of the level. If necessary, I can schedule time on the expensive hardware to get better data, but quite often the data provided by an inexpensive instrument would be all that was necessary.

Public schools, even those in poor areas, could afford at least some such instruments, which'd allow them to expose students to modern instrumental analysis techniques without busting the budget. College and university science departments could have ten or twenty of each instrument where they now have one or two, as could corporate and government labs.

I think the only reason this hasn't happened already is that no one with the ability to make it happen has seriously considered doing it. Obviously, Perkin-Elmer and other instrument suppliers aren't going to do it. They'd rightly assume that inexpensive analytical instruments would cannabalize sales of their expensive instruments.

Frankly, I'm surprised that the Chinese haven't done it, and I'm very surprised that MAKE hasn't published articles about building your own instruments from readily available parts. I'd do it myself, except I'm no instrument maker and I'm pretty hopeless at building things. But I may give it a try. If it works, perhaps I'll sell kits.

What I really want is a $100 tricorder. I wonder how long it'll be before I can buy one.



I actually wrote this yesterday and sent the text to some friends for a sanity check. Brian Jepson, my editor at O'Reilly, commented that MAKE actually has run an article on building an inexpensive spectrometer. As you might expect, that instrument has limited flexibility (for example, it uses five LEDs to test at only five specific wavelengths), but it shows what can be breadboarded with $100 worth of parts. And something that can be assembled as a one-off with $100 worth of parts can probably be manufactured in volume for $10 or $20.


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Tuesday, 19 August 2008
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07:45 - I know I'm strange, but some things bother me although other people don't give them a second thought. Or even a first one. Minor errors in TV programs, for example.

The other night Barbara and I watched S1D1 of the Showtime series Weeds. The sixth and final episode on that disc opens with the main character, played by Mary-Louise Parker, having an erotic dream featuring her and her husband before his untimely death. She awakens to find herself in bed, alone except for a talking stuffed animal, realizes that she'd been having a dream, and, after a moment's consideration, opens the drawer in her nightstand, from which she extracts a vibrator.

She turns on the vibrator and it twitches a couple of times before dying. So she looks around for a source of replacement AA cells. She spots the TV remote, opens it, pulls out the cells, and puts them in the vibrator. The vibrator comes to life, buzzing nicely, but it soon dies. Hmmm. So she continues looking around the room, until her gaze falls on the smoke detector. Cut to the next scene, with the smoke detector hanging open, batteryless, and her vibrator buzzing merrily away.

The problem is, I've never seen a smoke detector that uses anything but AC power or a 9V transistor battery. It's obvious in the video that her smoke detector in fact uses a 9V battery. So, for the next minute or so, I missed most of what was going on in the program because I was still wondering exactly how she shoe-horned that 9V battery into that vibrator. And, in a vibrator designed to use 3V (or perhaps 4.5V; it wasn't clear in the video), exactly what would happen if you delivered 9V to it? That made me think of Tim the Toolman Taylor and More Power. The scene with him clearing a clog in the kitchen sink with a gasoline-powered roto-rooter popped into my head and I started laughing.

Yes, sometimes it's not easy being me. The good thing is that my very odd thought processes are seldom obvious to others. If we'd been watching that scene with a group of friends, everyone--except possibly Barbara and Mary, who know me too well--would probably have assumed that I was laughing at her frustration when in fact I was laughing at the thought of the gasoline-powered roto-rooter. Perhaps it's just as well that few people know what I'm thinking.


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Wednesday, 20 August 2008
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08:38 - I finished up the chapter on Forensic Drug Testing yesterday, and got started on the chapter on Forensic Toxicology. I found myself again wishing for that $100 visual/IR/UV spectrometer and the $200 gas chromatograph. Without them, I'll just have to do the best I can.

I'm working right now on the lab session about determining salicylate concentration by visual colorimetry. Deaths from aspirin (salicylate) toxicity are relatively common (although less common than deaths from acetaminophen, which is really nasty stuff). Most salicylate poisonings are accidents or suicides, but forensic aspirin poisonings (murder) are not unheard of.

Salicylate ions form an intensely-colored violet complex with iron(III) ions. If I had that $100 spectrometer, I'd plot absorption of various known concentrations at a green wavelength, produce a linear graph, and match the absorption of the unknown against that graph to determine its concentration. I don't have the spectrometer, so I'll modify the procedure to substitute comparisons via the Mark I human eyeball, which is surprisingly accurate.

I have several other lab sessions planned for this chapter, including the Marsh Test and presumptive tests for alkaloids using the wonderfully-named Dragendorff Reagent. This is going to be a fun chapter.


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Thursday, 21 August 2008
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08:47 - I'm still working on the lab session for salicylate determination by visual colorimetry. Trying to keep things affordable and accessible often complicates matters. I'm constantly trying to strike a balance between affordability and the amount of time and effort that readers would have to expend to save a few bucks.

For example, I need a standardized salicylate solution. The easy way to make up a 500 mg/dL solution would be to tell the reader to dissolve 0.584 grams of sodium salicylate (14.36% of the gram molecular mass of sodium salicylate is sodium, so you need 584 mg to get 500 mg of salicylate ion) and make up the solution to 100.0 mL. But that presupposes the reader has an accurate balance and a supply of sodium salicylate, which I don't want to assume.

So, the obvious source of salicylate ions is aspirin, acetylsalicylic acid, which is cheap, readily available, and comes in conveniently pre-measured masses called tablets. But dissolving aspirin doesn't yield salicylate ions directly. We have to cleave the aspirin by reacting it with two equivalents of a base like sodium carbonate, sodium bicarbonate, or sodium hydroxide, which produces sodium salicylate in solution, along with only water and carbon dioxide as byproducts. So the obvious answer seems to be to have readers produce their own sodium salicylate from aspirin.

But there's a problem with that. In order to make sure that all of the aspirin reacts to form salicylate ions, we have to start with an excess of sodium carbonate, bicarbonate, or hydroxide. Unfortunately, if we do that, there'll be excess carbonate, bicarbonate, or hydroxide ions in the salicylate solution. And we're going to react that solution with a solution of iron(III) ions to produce the nice violet color. But iron(III) ions react with those excess ions to produce insoluble iron(III) carbonate or iron(III) hydroxide, which would skew our results. So, we have to make sure there aren't any excess carbonate, bicarbonate, or hydroxide ions present in the salicylate solution. That means we'd need to neutralize those ions by, say, adding hydrochloric acid dropwise until the solution tests as acid to litmus paper. And, of course, that 500 mg aspirin tablet doesn't yield 500 mg of sodium salicylate, so the actual concentration would need to be calculated and taken into account.

On balance, in this case, I decided it was better to assume that the reader has a balance and can order a small bottle of sodium salicylate for a couple bucks. So that's the way I'll write up the lab.


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Friday, 22 August 2008
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08:24 - So now Jerry Seinfeld is going to be featured in a new $300 million series of ads for Microsoft Vista. Incredibly, the new catchphrase is apparently "Vista is really better than you think", which should probably make the Top Ten list of all-time pathetic advertising slogans. That barely beat the second choice, "Vista. It's not as bad as everyone thinks it is." I think they should have gone with Charlie Demerjian's suggestion: "Vista. A chrome-plated turd."

Microsoft is running scared. Vista is a dead product, and they know it. OS X is starting to make inroads even in corporations, which for more than two decades have been Microsoft's stronghold. And, horror of horrors, corporations are actually starting to install Linux on desktop systems in significant numbers.

Windows 7, far from Microsoft's description of it as a major release, will actually be a dot release. In effect, Windows 7 will simply be the next Vista service pack, but it'll be a service pack that people have to pay good money for. The future of Windows looks bleaker every day. Midori, Microsoft's real new operating system, probably won't see the light of day until 2015, if then.

Anyway, the LAMP stack and web-based apps are increasingly making the choice of desktop OS immaterial. Office, which is even more important than Windows in maintaining the Microsoft monopoly, is under threat, with Microsoft's failed attempt to force the proprietary OOXML format down all our throats.

Microsoft can't win for losing. They're right to be running scared.



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Saturday, 23 August 2008
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09:45 - Barbara and I have been doing a Weeds marathon. The three series three discs are due to arrive today from Netflix, so we should be caught up by the time I return them on Monday, at least until series four releases on DVD.

One of the striking things about the series, at least to me, is the amount of science involved in growing good marijuana. I mean, they're not just talking about hydroponics and proper fertilizers and so on, but they're creating hybrids and clones and doing genetic engineering. Although they talk about the science only in passing, what they do talk about is good science rather than the bogus stuff that usually passes for science on TV.

I never had any interest in mind-altering drugs. Heck, I was in high-school and college in the late 60's and early 70's, the height of sex, drugs, and rock-and-roll, and I never got high. To me, the idea of altering my mind was profoundly distasteful. I liked my mind exactly as it was. I wasn't all that interested in rock-and-roll, either.

But if I had been interested in drugs, I'd like to think that I would have approached the matter scientifically.



Barbara is off to Wal*Mart this morning. Although we prefer not to shop there, they're the only place locally that carries Alpo Snaps in large boxes. Our dogs go through a lot of Alpo Snaps, so Barbara goes to Wal*Mart occasionally and grabs as many boxes as they have on the shelves, usually half a dozen or so.

Since she's going to Wal*Mart anyway, she's going to do the grocery shopping while she's there. I asked her to pick up some quinine water for me. I'm going to use it in the lab session on quantitative analysis of alkaloids. When I mentioned it to her, the subject of pronunciation of chemical names came up. I called it kwih-neen' water. Barbara pronounces it kweye'-nine water.

Same thing with other chemical names. I pronounce "iodine" correctly as eye-oh-deen, analogously with fluorine, chlorine, and bromine. Barbara (and just about everyone else) pronounces it eye-oh-dyne. Too many vowels in the word, I guess. In chemistry, the "ine" ending is prounced "een", as in amine, quinine, and all of the other alkaloids. In fact, the original spelling of benzene was benzine, a spelling that is still used in some parts of the world.

Which reminds me of one sure test to determine if someone is a chemist. Write down a group of words at least vaguely related to science including "unionized" and ask him to read the list of words. Everyone else will pronounce it you-yun-eyezd. The chemist will pronounce it un-eye-un-eyezd.



11:52 - For the first time, I used one the chemicals in my lab for a household purpose. Actually, it was intended for household use, so I didn't break any laws or violate any regulations.

While Barbara was out running errands, I decided to take a shower. I started the shower running to warm it up. As I was standing at the sink brushing my teeth, I noticed a strange odor. When I looked over to the shower stall, the bottom of it was covered in standing water with a bunch of dirt and crap floating in it.

I got dressed, and looked under the kitchen sink for some Liquid-Plumr, which is actually pretty much laundry bleach with a bit of extra sodium hydroxide (lye) and a surfactant. We didn't have any of that, so I decided to use the nuclear option. I went into my lab, poured out a fair amount of Roebec Crystal Drain Opener (100% sodium hydroxide), and took it up to our bathroom. The label says to use 2 tablespoons to unclog a drain, so I figured two or three (or four or five) times that much for a shower drain.

When I popped over the drain cover, a huge clump of hair came with it. Aha. At that point, the drain seemed to be running, but I dumped the sodium hydroxide down it anyway, along with a couple pints of water. The instructions said to let it work for something like 20 minutes, but I decided five or ten minutes was probably enough. That's long enough for a saturated solution of sodium hydroxide to convert fats to soap and make a good start on dissolving keratin (hair). I was concerned because the trap is PVC and I didn't want to risk melting it. So, after five or ten minutes, I turned on the cold tap and let it run for 15 minutes or so. That should be long enough to flush out the trap completely and make a good start on flushing out the main drain line.

The drain runs fine now, but I never did take my shower.


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Sunday, 24 August 2008
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Robert Bruce Thompson. All Rights Reserved.