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Caltech Researchers Weigh Individual Molecules

CowboyNeal posted more than 9 years ago | from the heavy-lifting dept.

Technology 130

karvind writes "PhysOrg reports that physicists at the California Institute of Technology have created the first nanodevices capable of weighing individual biological molecules. This technology may lead to new forms of molecular identification that are cheaper and faster than existing methods, as well as revolutionary new instruments for proteomics. The Caltech devices are 'nanoelectromechanical resonators' -- essentially tiny tuning forks about a micron in length and a hundred or so nanometers wide that have a very specific frequency at which they vibrate when excited. Slashdot covered earlier the effort by Cornell for measuring attogram objects which also employs NEMS cantilevers."

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April 1st!!! (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12108824)

April 1st!!!

Re:April 1st!!! (0)

Anonymous Coward | more than 9 years ago | (#12108855)

Next time do some research - the PhysOrg news post was made on 29th March...

Re:April 1st!!! (4, Funny)

Spad (470073) | more than 9 years ago | (#12108863)

Slashdot, where the April Fools jokes get posted on the 3rd of April and again on the 4th.

Re:April 1st!!! (1)

CHESTER COPPERPOT (864371) | more than 9 years ago | (#12109015)

April 1st should just be renamed "Day of the Troll."

I applaud you Sir. (0)

Anonymous Coward | more than 9 years ago | (#12108867)

..but it's still April 1st!!! today, ...Sir...

Since TFA totally sucks.... (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12108860)

and I do not plan to RTFA, here is a more "stuff that matters" topic: ...where do you guys get your pr0n from? TGPs suck recently.

Re:Since TFA totally sucks.... (1)

Troll McClure (571760) | more than 9 years ago | (#12108871)

p2p IT r0x0rz!!!!!

Really? (0, Offtopic)

dotslashdot (694478) | more than 9 years ago | (#12108825)

Are you calling me F2A6T12?

first post (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12108827)

cal tech rules!!!!!!

Finally! (4, Interesting)

InternationalCow (681980) | more than 9 years ago | (#12108838)

Now we can really measure how many angels can fit together on a pinhead! More seriously, this technology opens up interesting possibilities for high-througput easy mutation screening. Base substitutions (mutations) in a given stretch of DNA will obviously alter its weight. In this way you can easily (well, relatively speaking) detect the presence of a mutation, after which you can select the stretch of DNA that the mutation is in for sequence analysis. It'd be an interesting application for us geneticists.

Re:Finally! (1)

tanverenzo (849273) | more than 9 years ago | (#12108889)

Another more practical use for this technology is to screen for mutated proteins already transcribed in cells. Differences in weights of proteins are much easier to detect than differences in weights of DNA molecules simply because amino acids are much larger than nucleotides.

Re:Finally! (1)

dan dan the dna man (461768) | more than 9 years ago | (#12108893)

I'm still not sure how this would be any more high throughput than RFLP, SSCP, microarray or Taqman assay (or even straight sequencing!) for SNPs/mutation screening.. I mean you'd have the problem of separating out the fragments of DNA first to get exactly the one you wanted in order to weigh it individually, make sure it was completely uncontaminated with protein.. that doesn't appear to me to lend itself to high-throughput techniques.

There are of course loads of biological uses for this kind of technology. Also this story was run yesterday on Technocrat [technocrat.net] , which has a link to the BBC coverage

Re:Finally! (2, Interesting)

tanverenzo (849273) | more than 9 years ago | (#12108914)

If you had RTFA, then you would have found that the machine is not precise enough to measure SNPs (single nucleotide polymorphisms) in DNA--a common cause of or marker for many genetic disorders (sickle cell anemia immediately comes to mind). Indeed, the mutation would have to be extreme (spanning 100s of nucleotides) for there to be an appreciable weight difference. And even if the DNA were that damaged, its corresponding protein would be misshaped enough for scientists to pick up.

Medical Use (5, Funny)

bobbuck (675253) | more than 9 years ago | (#12108936)

Doctors and hospitals need this techology right now so they can weigh patients like Calista Flockhart.

Re:Medical Use (1)

lukewarmfusion (726141) | more than 9 years ago | (#12109930)

Apparently, you have some technology to transport us back to humor in 1998!

Fantastic!

Re:Medical Use (1)

krymsin01 (700838) | more than 9 years ago | (#12109976)

Hey did you hear the one about Clinton, Starr, and the cigar salesman walking into a bar together?

Privacy (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12109071)

Like RFID, this kind of work obviously has detrimential implications for privacy. We need strict regulation of this technology in order to preserve our rights. If the governments don't abuse it, the corporations will.

Re:Privacy (0)

Anonymous Coward | more than 9 years ago | (#12109118)

If you'd kept your tin hat on the article wouldn't even have bothered you.

Re:Finally! (0, Troll)

drsquare (530038) | more than 9 years ago | (#12109268)

It's an April Fool's joke you idiot. Weighing molecules, what idiocy. Like you can make a molecule-sized set of scales to weight it on. Not to mention that molecules don't weight straight down like objects, they float about, so wouldn't press down on the scales. The rest of the article is filled with pseudo-science drivel to try to look clever and hide the fact that they're making the whole thing up.

What happened to the days when April fools stories were at least slightly plausable?

Re:Finally! (1)

Anomylous Howard (666178) | more than 9 years ago | (#12109458)

Man, I wish I could mod this as a +1 troll.
Beacuse on some days some trolls are good!

No it's not (4, Informative)

Mr. Underbridge (666784) | more than 9 years ago | (#12109467)

It's an April Fool's joke you idiot. Weighing molecules, what idiocy. Like you can make a molecule-sized set of scales to weight it on. Not to mention that molecules don't weight straight down like objects, they float about, so wouldn't press down on the scales. The rest of the article is filled with pseudo-science drivel to try to look clever and hide the fact that they're making the whole thing up.

I'm familiar with his research, half my group collaborated with him, and I think I met him once. It's real. MEMS-based cantilever technology has been getting progressively better, this isn't particularly surprising.

I don't know why you're surprised that New Scientist is pseudoscience, but you can find similar results with real science in journals. Look up Roukes, M in "web of science" or something.

Nice troll, but I can't have you confusing the n00bs on matters scientific.

Re:No it's not (1)

fearofcarpet (654438) | more than 9 years ago | (#12109795)

It's an April Fool's joke you idiot. Weighing molecules, what idiocy. Like you can make a molecule-sized set of scales to weight it on. Not to mention that molecules don't weight straight down like objects, they float about, so wouldn't press down on the scales. The rest of the article is filled with pseudo-science drivel to try to look clever and hide the fact that they're making the whole thing up
Indeed. I shared an office with a physicist working on essentially the same thing at IBM and I gan assure you it wasn't pseudo-science. There are plenty of "real" journals in which this research has been published. The reason you don't see them on Slashdot is 'cause they cost money to look at unless your institution pays for a subscription.

Re:Finally! (2, Funny)

Frankie70 (803801) | more than 9 years ago | (#12109286)


Now we can really measure how many angels can fit together on a pinhead!

I am a pinhead, you insensitive clod!!!!

Yeah right (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12108839)

Like I'm gonna believe this is real. April fools.

Cool tech. Some issues (5, Insightful)

Dancin_Santa (265275) | more than 9 years ago | (#12108844)

I was under the impression that at the atomic and molecular level there were quantum phenomena that caused particles to gain and lose mass depending on how they are arranged within the atom/molecule. For example, (just making something up) a molecular bond would result in the total mass of a molecule being less than the sum of the masses of its atoms.

If working with isotopes, it seems feasible to measure the mass of any particular molecule. What were the issues that were blocking this sort of measurement before?

Re:Cool tech. Some issues (0)

Anonymous Coward | more than 9 years ago | (#12108881)

You can't gain or lose mass by rearranging the layout of the objects that have the mass.

I have no idea where you got this from.

Re:Cool tech. Some issues (5, Informative)

RWerp (798951) | more than 9 years ago | (#12108883)

You're right that the bonds make the total mass smaller. But we're talking about stable molecules here, which bonded in one specific way. If their mass were to change, they would have to decay or interact with the environment. If the molecule is stable, it's energy is very well defined. The only limiting factor is the principle of uncertainty, which basically tells here, that the longer you measure the mass, the more precise you are. So the deviation of the measurement may change, but not its expectation value. It would be very interesting, however, if we could apply this -- or other -- technique to measuring masses of unstable molecules and watch how it changes in time.

Re:Cool tech. Some issues (2, Informative)

fearofcarpet (654438) | more than 9 years ago | (#12109998)

You're right that the bonds make the total mass smaller. But we're talking about stable molecules here, which bonded in one specific way. If their mass were to change, they would have to decay or interact with the environment. If the molecule is stable, it's energy is very well defined. The only limiting factor is the principle of uncertainty, which basically tells here, that the longer you measure the mass, the more precise you are. So the deviation of the measurement may change, but not its expectation value. It would be very interesting, however, if we could apply this -- or other -- technique to measuring masses of unstable molecules and watch how it changes in time.

Huh? You're going to have to explain to me how you bonds change the mass of a molecule... Especially decreasing it. I'm really curious where you heard this. Perhaps there is some nuance to this statement that I'm missing? Are you saying that the mass of the constituent atoms is different than that of a molecule? This can certianly be true if electrons are gained or lost, but chemical bonds don't affect anything beyond the valence electrons of the atoms. As for uncertainty - I'm not buying it. Even if there was a teeny tiny mass "change" over time, you'd be hard pressed to observe it, especially when you're talking about molecules weighing thousands of Daltons... The difference in scale would be like trying to measure the mass you loose from expelling carbon dioxide while standing on your bathroom scale - and having to take into account mass loss to water evaporation, skin exfoliation, etc. Macromolecules, especially biological molecules, have static charge build up, hydration, aggregation, etc. all contributing to a very dynamic system.

At any rate the "mass of a molecule" is an average of all the weights based on the natrual abundance of isotopes because that is the only factor that affects the mass of two molecules with the same empirical formula. "Unstable" molecuels loose mass by becoming different molecules. It is incorrect to say that a molecule's weight changes - that is impossible (save radioactive decay) because when the empirical formula changes, you no longer have the same molecule.

At any rate, it is an interesting challenge to identify biological molecules by weighing them one at a time, as the horrific isotope distribution in the mass spec of any macromolecule demonstrates.

Re:Cool tech. Some issues (2, Interesting)

tanverenzo (849273) | more than 9 years ago | (#12108945)

Since E=mc^2, m=E/c^2 Thus, a chemical bond (a storehouse of potential energy) can contribute to the mass of a molecule. The more "energetic" the bond, the more energy it stores, and hence the more mass it has to contribute to the overall molecule. Since, some bonds (and hence configurations) are more "energetic" than others then different configurations result in different overall masses for the same molecule. However, the contribution of mass is so small (by a factor of 1/c^2), it greatly diminishes (relatively) as the size of the molecule increases. Since this weighing machine can only detect the mass of a molecule greater than the equivalent of 30 xenon atoms, the configuration of the molecule doesn't make too much of a difference.

Re:Cool tech. Some issues (1)

marcosdumay (620877) | more than 9 years ago | (#12110089)

The mass of the atoms is almost all contained on the nucleus. Also, the mass of the eletrosfere is almost all contained on the inner electrons (except for the lighter elements, that don't have them).

Also, the mass lose due to the arrangement of the atoms on a molecule is a tinny error when compared to the lose due to the bound between the electrons and the nucleus and the resting mass of the electrons. The last ones are a tinny error when compared to the nuclear particles bound, and the last one is a small error when compared to the resting mass of those particles. So, the molecular bounds doesn't make much difference.

Crazy (1)

soniCron88 (870042) | more than 9 years ago | (#12108845)

Call me crazy, but has there been a relatively recent boom in nanotechnology? Seems like there's at least 2-3 new breakthroughs each *day* now!

It's true, but... (5, Funny)

Dancin_Santa (265275) | more than 9 years ago | (#12108852)

has there been a relatively recent boom in nanotechnology?

They are all really small breakthroughs.

BOOOOO!!1!!11testing1212 (0)

Anonymous Coward | more than 9 years ago | (#12108966)

+5 suicide-inducing jeux de mots goodness.

Re:It's true, but... (0)

Anonymous Coward | more than 9 years ago | (#12109937)

I hate this kind of post.

Dancin_Santa, that's really small of you.

Re:Crazy (1)

nucal (561664) | more than 9 years ago | (#12108951)

There's been a recent boom in labeling ongoing research projects with the buzz word "nanotechnology" to make them seem "sexier" ...

Re:Crazy (1)

myukew (823565) | more than 9 years ago | (#12109056)

Yeah, for example those insane battery-life-increasing-stickes! I suggest you buy one immediatly! The battery-life of my devices has increased significantly!

Wow! (-1, Offtopic)

snotclot (836055) | more than 9 years ago | (#12108848)

Wow! This is so exciting! / First 5 posts. Woohoo.

weigh station (5, Funny)

Lotharjade (750874) | more than 9 years ago | (#12108849)

Who will be stuck working the nano-weigh station of the future? Sounds like a crappy job with a Small paycheck.

Re:weigh station (1)

johannesg (664142) | more than 9 years ago | (#12108994)

I think it makes an excellent opportunities for small businesses to jump into ;-)

Re:weigh station (1)

flynns (639641) | more than 9 years ago | (#12109019)

Sorry! This joke can only be made once [slashdot.org] ! per day

Better luck next time.

Re:weigh station (1)

johannesg (664142) | more than 9 years ago | (#12109054)

I beg to differ: this is Slashdot, Home of the Dupe. If the editors can do it so can we!

Besides, I figured there was only a small chance anyone might notice... ;-)

Nickle-and-Dime (4, Funny)

Renraku (518261) | more than 9 years ago | (#12108850)

In other news, these devices are being utilized in the brand new series of gas pumps designed to pump gas throughout the next century.

"We're very excited about this new technology." says an anonymous CEO of a Fortune 500 oil company.

"No longer can the customer get a free $.009 with every purchase. They'll now be billed down to the exact molecule. Its a tough measure, but those freeloaders were really putting a strain on our budgets."

Re:Nickle-and-Dime (-1, Redundant)

Anonymous Coward | more than 9 years ago | (#12109000)

Won't the costs of doing this exceed the amount they gain from the customers?

Any informed people care to comment on this?

Vibrate when excited? (3, Funny)

Cruithne (658153) | more than 9 years ago | (#12108853)

Thats funny... doesnt excitement usually occur because of vibrating, not the other way around? And if this is true, could be devise some sort of perpetual excitement/vibration motion device involving women and 'nanoelectromechanical resonators'? Or perhaps a beowulf cluster of the aforementioned.... *consults the man page for 'woman'* This post a product of SlashPost generator v 0.4.1 alpha build 0138 with SlashClicheMod 2.0

You should upgrade (1, Funny)

Jesus_666 (702802) | more than 9 years ago | (#12109607)

v 0.4.2 has support for linebreaks.

Resolution (2, Interesting)

lachlan76 (770870) | more than 9 years ago | (#12108856)

In their experiments this represents about thirty xenon atoms-- and it is the typical mass of an individual protein molecule

If they can resolve down to one protein mass, then wouldn't that imply that at this point they can not find the difference between molecules?

Re:Resolution (2, Informative)

operon (688118) | more than 9 years ago | (#12109113)

proteins does not have a typical mass. They have a wide range of masses, with molecules having few aminoacids to large and complex quaternary strucutures.

Fool me once... (4, Funny)

gnovos (447128) | more than 9 years ago | (#12108888)

Caltech Researchers Weigh Individual Molecules
Technology
Science
Posted by CowboyNeal on Friday April 01, @01:31AM
from the heavy-lifting dept.


Ha ha ha! I get it, I get it.
"nano" machines, "molecules" "Caltech"

You got me AGAIN! Man, CowboyNeal, you sure pulled the wool over my eyes. Ha ha ha. Whew, that was a good one.

Re:Fool me once... (0)

Anonymous Coward | more than 9 years ago | (#12108901)

Uh. Can I subscribe to your newsletter?

April fools....? (1, Funny)

red5 (51324) | more than 9 years ago | (#12108905)

Where is the joke? I don't get it.

Re:April fools....? (0)

Anonymous Coward | more than 9 years ago | (#12108970)

I have a feeling that April Fool's for /. this year will be that there are no April Fools stories...

At least that's what I'm hoping :)
(Until the Google post I was thinking that they might do an April Fools by not posting any stories until after 12 midday (the time April Fools is supposed to end) but that wasn't to be :)

Re:April fools....? (0)

Anonymous Coward | more than 9 years ago | (#12108971)

Actually, props to Slashdot for NOT doing the tired April Fool's Day thing this year ...

Re:April fools....? (0)

Anonymous Coward | more than 9 years ago | (#12109587)

I take it back - Taco's doing April Fool's posts.

Bleah ...

Re:April fools....? (0)

Anonymous Coward | more than 9 years ago | (#12109066)

"Gentlemen," said Gussie, "I mean ladies and gentlemen and, of course, boys, what a beautiful world this is. A beautiful world, full of happiness on every side. Let me tell you a little story. Two Irishmen, Pat and Mike, were walking along Broadway, and one said to the other, 'Begorrah, the race is not always to the swift,' and the other replied, 'Faith and begob, education is a drawing out, not a putting in.'"

I must say it seemed to me the rottenest story I had ever heard, and I was surprised that Jeeves should have considered it worth while shoving into a speech. However, when I taxed him with this later, he said that Gussie had altered the plot a good deal, and I dare say that accounts for it.

(P. G. Wodehouse, Right Ho, Jeeves, ch. 17)

The joke is... (2, Funny)

DigiShaman (671371) | more than 9 years ago | (#12109128)

The joke is that you THINK it's a joke when in fact it's not. Ha ha.

The problem as I see it (4, Funny)

minginqunt (225413) | more than 9 years ago | (#12108908)

Is that the problem with this picoscillatory nanoids is that their normal modes have a tendency to reverse the polarity of the neutron flux through the quantum mass matrix.

This has the unfortunate effect that at that point, you have little choice when determining the altoid-dense uberstate discrepancy to assume that the entire universe weighs exactly the same as Cheryl Tweedie from Girls Aloud.

Hooray for physics.

Re:The problem as I see it (1)

Jesus_666 (702802) | more than 9 years ago | (#12109622)

Is that the problem with this picoscillatory nanoids is that their normal modes have a tendency to reverse the polarity of the neutron flux through the quantum mass matrix.

But if we reroute energy to the interocitor and reconfigure the main deflector to emit bogon radiation it might just work.

Useful (1)

eclectro (227083) | more than 9 years ago | (#12108916)


This will make it easier for the clerk to know how much to charge me for my nanoparts when I check out.

Re:Useful (1)

spywhere (824072) | more than 9 years ago | (#12109130)

my nanoparts

It's not how big they are, Eclectro: it's what you can do with them.
That's what women have been telling me, on the third date, for years...
I wonder why there's never a fourth date?

Here we go again....! (4, Insightful)

Le_Batleur (822375) | more than 9 years ago | (#12108918)

You know, I'm not going to believe one darned word posted today on Slashdot. If anybody has any news they want people to believe, post it tomorrow. Imagine what would happen if the BBC or CNN sprinkled six or seven fake stories into their broadcasts like Slashdot do every year....

Re:Here we go again....! (1)

ethnocidal (606830) | more than 9 years ago | (#12108982)

Yeah, imagine what would happen if the BBC posted [bbc.co.uk] a story which was so obviously an April Fool's gag!

Re:Here we go again....! (1)

dokkeri (868014) | more than 9 years ago | (#12109039)

April fools "news" items are actualy quite good for theaching people to be critical about the things they hear on the media.

If it helps any... (1)

ubernostrum (219442) | more than 9 years ago | (#12109074)

I saw this elsewhere the other day, and the timestamp on the linked story is 29 March. So I think this one's safe.

Re:Here we go again....! (0)

Anonymous Coward | more than 9 years ago | (#12109264)

Imagine what would happen if the BBC or CNN sprinkled six or seven fake stories into their broadcasts
Or if CBS reported events using fake National Guard memos?

So, when will you read /. then? (0)

Anonymous Coward | more than 9 years ago | (#12109487)

It's not like there's any noticeable difference today.

Re:Here we go again....! (0)

Anonymous Coward | more than 9 years ago | (#12109732)

What? You mean sometimes Slashdot posts NEWS that's REAL? I thought it was April 1 all year round here.

Re:Here we go again....! (1)

jnik (1733) | more than 9 years ago | (#12109954)

Frankly, I don't believe much posted on physorg from 1 Jan to 31 Dec. I've seen a few stories there (both in the news section and blog section) that didn't pass the sniff test and weren't confirmed elsewhere. Grain of salt always recommended.

Re:Here we go again....! (1)

PxM (855264) | more than 9 years ago | (#12110169)

How the hell is that insightful? I would hope that slashdotters have enough common sense to be able to figure out a real story from a joke one. (Yes, I'm a rabid optimist. Why do you ask?) Even if the blurb is confusing due to the nature of the strange stories that are sometimes posted, it should become obvious once you actually click the link whether the story is serious or not. Then again, maybe that's too much to hope for.

--
Want a free Nintendo DS, GC, PS2, Xbox. [freegamingsystems.com] (you only need 4 referrals)
Wired article as proof [wired.com]

There goes the neigbourhood (2, Funny)

tezza (539307) | more than 9 years ago | (#12108926)

Your Honour,

The defendant stands charged for posession of with intent to supply, 300 zeptograms of 3,4-methylenedioxymethamphetamine, a Class A prohibited substance under ... [austlii.edu.au]

uhh... so what? (1)

3.09 a hour (812839) | more than 9 years ago | (#12108930)

You know, last i checked we allready knew the mass of all the molecules. On top of that, theres what... 1000 of them top (counting ions and the like) doesnt seem all that useful to me.

Re:uhh... so what? (1)

Walkiry (698192) | more than 9 years ago | (#12108996)

> doesnt seem all that useful to me.

Two words: Biological Macromolecules.

Re:uhh... so what? (3, Informative)

FirienFirien (857374) | more than 9 years ago | (#12108997)

We know the masses of a lot of the atoms (though there's a lot more than 1000 isotopes). Molecules are a completely different matter; there's an infinite range of possible molecules, because you can put them together in a lot of different ways; chain molecules (like DNA (hey, there's 5 billion different molecules - and that's only counting humans!)) are difficult to untangle and sort out; when you can weigh them, you can use the masses of atoms to try to calculate how many of each atom is in the molecule, and from there you can try and work out which configurations of atoms are possible.

Re:uhh... so what? (2, Informative)

mamladm (867366) | more than 9 years ago | (#12109006)

As I understand it, one of the more useful applications envisaged for the technique is not to find out what the actual weight of a given molecule is, but to detect the presence of a particular molecule, such as certain proteins which are present in blood in the very early stages of cancer and which are very difficult to detect with today's methods.

Re:uhh... so what? (1)

bcattwoo (737354) | more than 9 years ago | (#12109804)

Last I checked you did't seem to know the difference between an atom and a molecule.

Finally (5, Funny)

aussie_a (778472) | more than 9 years ago | (#12108948)

An instrument that can now weigh my penis.

Wait. Did I say that outloud? I guess I better turn off my spam-blocker.

Re:Finally (0)

Anonymous Coward | more than 9 years ago | (#12109495)

(insert thats-a-long-chain molecule joke)

Amazing... (2, Insightful)

RobertKozak (613503) | more than 9 years ago | (#12108964)

Its just amazing how colored our perception can be of a story.

When I first read it I assumed it was an infamous April 1 slashdot story so each comment I read was biased based on that perception.

I either thought you were an idiot for replying intelligently to this story or that you were extremely witty and sly in your reply and that demonstrated that you got the joke.

But I did something we rarely do and went to read the story and found it was written 2 days ago.

I guess the joke is on me....oh well at least I can read all about it again tomorrow. -- Robert

Re:Amazing... (0)

Anonymous Coward | more than 9 years ago | (#12109144)

Blue... no red...

Re:Amazing... (1)

lisaparratt (752068) | more than 9 years ago | (#12109934)

You can tell the which aren't April fools stories - the original story didn't fall on April 1st last year.

Mass spectroscopy (2, Informative)

FirienFirien (857374) | more than 9 years ago | (#12108985)

This is the next step from a process called mass spectroscopy, where a molecule is given + or - one electron, then fired through a calibrated magnet to hit a target. If the magnet is calibrated so that a single charge on a molecule of weight W deflects by exactly n degrees, then if the molecule weighs W it will hit the target, and you know the mass of your molecule.

It's more trial-and-error than TFA, but with a sweep across the calibration settings you get lovely graphs showing how much of a mixture is which compound. It's fast (seconds for a full-range mass chart), which I somehow doubt TFA is quite up to yet - maybe for a single molecule, but something in the description rankles of a slow process.

Actually it's called mass spectrometry (1, Informative)

Anonymous Coward | more than 9 years ago | (#12109301)

This is the next step from a process called mass spectroscopy, where a molecule is given + or - one electron
A molecule can not be "given" an electron is mass spec. Ions are generated by ejecting an electron or breaking a bond forming a positive species and a negative radical. Only postive species are detected.
then fired through a calibrated magnet to hit a target.
What you're describing is a magnetic sector mass spec but there are many other types.
If the magnet is calibrated so that a single charge on a molecule of weight W deflects by exactly n degrees, then if the molecule weighs W it will hit the target, and you know the mass of your molecule.
Close. What you're actually detecting is the mass to charge ratio (m/z). The way it works is that the +'ve ions are accelerated by a constant voltage that gives all ions the same kinetic energy. The molecule then continues though the instrument where it encounters a magnetic field which causes it to deflect. Only ions with the correct m/z ratio will be deflected perfectly around a bend and reach the detector. Other ions will be deflected too much or not enough. The spectrum is swept by altering the field strength For most peaks in a mass spectrum the charge (z) is +1 so the m/z ratio is in fact just m however species with greater charge are generated. In this case the peak appears to arise from a lighter ion but in reality that ion just experienced a greater force from the deflecting field due to the higher charge. For the analysis or proteins you generally interested in the molecular ion (the intact molecule less an electron) as this directly reviles the mass of the protein. To do this "soft" ionization methods such as electrospray and MALDI mass spec are used. This is different from "hard" ionization which breaks apart molecules into many ions which are detected individually. Structural information can be gained by examining how the molecule fragments. This isn't as useful for proteins because they are so large.

Re:Actually it's called mass spectrometry (1)

dsci (658278) | more than 9 years ago | (#12109701)

A molecule can not be "given" an electron is mass spec. Ions are generated by ejecting an electron or breaking a bond forming a positive species and a negative radical. Only postive species are detected.

That's not true at all. Ever heard of NEGATIVE ion chemical ionization? I've done this A LOT. This is not that uncommon.

Indeed, there are plenty of researchers doing negative ion work.

For the analysis or proteins you generally interested in the molecular ion...examining how the molecule fragments. This isn't as useful for proteins because they are so large.

Again, not so. You need to research the MS techniques used in protein sequencing; very big field. True, the MI is one desired datum, but the sequence is important (and measurable, or at least chunks of it) as well. See MS/MS, MS/MS/MS/ MS/MS/MS/MS, etc (ion trap techniques), electrospray, etc.

Re:Mass spectroscopy (1)

dsci (658278) | more than 9 years ago | (#12109730)

you get lovely graphs showing how much of a mixture is which compound.

Not quite. Mass spectrometry itself is used for pure compounds.

The lovely graphs showing the components of mixtures of which you are thinking I believe are chromatograms (a mass spectrometer can be used as a gas or liquid chromatograph detector).

Who says Americans don't understand irony? (3, Funny)

panurge (573432) | more than 9 years ago | (#12108990)

Posting an absolutely straight story with accurate detail, but which sounds like it might be a fake...on 1st April.

That, my friends who use "irony" when you mean "paradox" or just "contradictory" - that is not only real irony, it's inverted irony. Full marks.

Re:Who says Americans don't understand irony? (1)

FirienFirien (857374) | more than 9 years ago | (#12109003)

Then again, how can you be sure that the irony was intentional? This doesn't prove that they understand it ;)

Re:Who says Americans don't understand irony? (2, Funny)

FidelCatsro (861135) | more than 9 years ago | (#12109080)

not as bad as people confusing Irony and ironic ,
To explain irony i just quote the dictionary definition
!: contraining or apearing to contain Iron
That my freinds is irony

Re:Who says Americans don't understand irony? (0)

Anonymous Coward | more than 9 years ago | (#12109083)

You can now expect a barrage of corrections from people who don't get it..

Re:Who says Americans don't understand irony? (0)

Anonymous Coward | more than 9 years ago | (#12109104)

Dude Respect , That works on so many levels .
If you truely understand irony its funny , if you dont understand irony properly it's still funny ..

Alanis Morissette is Canadian (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#12109510)

And she's the biggest culprit on the planet.

Was Avogadro's number right? (1)

AsparagusChallenge (611475) | more than 9 years ago | (#12109022)

Inquiring minds want to know!

I think it's great... (5, Funny)

Godwin O'Hitler (205945) | more than 9 years ago | (#12109041)

...that they're naming these new units after stars of the past. After zeptograms we'll no doubt be seeing grouchofarads, chicobytes, and harpohertz.

Wrong units (0)

Anonymous Coward | more than 9 years ago | (#12109531)

That would be moehertz after curlybytes. :)

this is all great (-1, Offtopic)

wildchild978 (458123) | more than 9 years ago | (#12109102)

but can they solve hair loss?

Weighing individual molecules eh? (1)

FrostedWheat (172733) | more than 9 years ago | (#12109117)

Nitrogen Triiodide: "Does my bum look big in this?"

They can't really do that! (1)

camcloud1 (758094) | more than 9 years ago | (#12109284)

It's an April Fool's Day joke. Don't you get it!

So.... (1)

lilricky (632829) | more than 9 years ago | (#12109303)

The whole atomic weight thing was just a best guess then? Or have we been able to calcuate atomic weights, but when it comes to molecules, well, thats just too darn complicated?????

Re:So.... (1)

Iason Baldes (784528) | more than 9 years ago | (#12110080)

no they just defined one mole as 12g of carbon 12. So 1 mole of carbon12 (6.023x10^23 particles) has a mass of 12g. Therefore it's said to weigh 10g mol^-1

I wonder.... (1)

jetsfandb (446202) | more than 9 years ago | (#12109887)

How much the weighing device weighs?
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