Sunday, June 25, 2006

Plasma in the window

You know a lot of people play Sudoku and work crossword puzzles to exercise their mind. Any chemists out there ever try to draw out syntheses for natural products or any other molecules to gain extra brain power? Here's a shot of the plasma from the lab.

The color of the plamsa is actually white, but the window is tinted green with something that prevents the UV light from harming our eyes. The ultraviolet light is emitted from the metals in the water samples after they gain energy from the plasma. There is actually no reason for the window at all, it just looks cool.

Monday, June 19, 2006

Quality Control Explained

Quality control in ensuring your product, or scientific result falls in between a set of guidelines determined by the necessary amount of accuracy and precision required. It allows a customer to know how reliable a scientific result is.

For instance, say you want to analyze some water samples from off the coast of Louisiana to check if there is any lead contamination because the battery factory was flooded and damaged from a hurricane. To start with, you might want to take samples in various locations and record some type of data like distance from shore and maybe depth of sample taken along with the pH of the water. To tell that the guy or girl sampling the water hasn't contaminated it themselves, they'll need to take some DI water up with their water sampling equipment and bottle that up to go with all the sea water samples.

Then, it'll get back to the lab and it will have to be prepared to be analyzed, the preparer will include another blank with the batch of sea water samples to ensure that he or his lab did not contaminate the samples. These blank samples are representative of the whole batch of samples, if they have any lead in them, then all the other sea water samples would be expected to have the same amount. That's why you gotta keep it all clean, with a mass spec you're usually looking for pretty low amounts.

To be continued... as a series or possibly just a trilogy.

Wednesday, June 14, 2006

Alpha hydroxy garbage

This is kinda funny. After studying organic chemistry, whenever those commercials came on TV about "alpha hydroxys" in skin creams and stuff I would laugh and say that doesn't mean anything. I tried to explain to my girlfriend that the term alpha hydroxy just describes a location on a molecule, like the next carbon over from something has an alcohol bonded to it. In other words, the alcohol (hydroxy) is alpha (next to) something, but you can't really tell what that something is when you say alpha hydroxy.

Glycolic acid

Some of the commercials say "alpha hydroxy acids". This makes much more sense, turnes out, there is a group of molecules called alpha hydroxy acids. And they do have an effect on skin.

Another thing that tickles my fancy is seeing all those little multi-colored beads mixed in and suspended in the face wash or shampoo. That is actually some hot research because just the way it looks sitting on the grocery store shelf makes people buy it. So there were actually scientist out there trying to find out how to suspend little colored balls in a hair gel, making and spending loads of money. It's just the way it goes. Kinda seems like a waste of scientific talent to me, maybe the project only took a couple years.

Next up, beta hydroxy acids.

Friday, June 09, 2006

New calibration standards

Calibration standards have to be made in order for the mass spec to correlate the intensity of the ion signal to concentration. You can't just turn it on and stick a sample in and get a result of 50ppb Cd like on CSI. (A mass spec finds atoms of interest in big piles of random atoms). What would happen if you did that is you would get some random result such as 564,000 CPS (counts per second). When I "calibrate" the instrument by analyzing a 25ppb (10,000CPS), 50ppb (20,000CPS), and 100ppb (40,000CPS) at the beggining of the run, then the instrument knows what 564,000 CPS is. Yes, if you graphed intensity (CPS) vs. concentration (ppb), it would be linear, that's how it works. Technically, 564,000 CPS is obviously overcal in this example and would have to be rerun diluted.

Back to the calibration standards, or multi-element solutions, these are a pain to make. You take bottles off the shelf such as 10,000ppm Sb, it's dissolved in acidified D.I. water from some kind of compound like Sb2O3. You take about 20 to 30 of these bottles off the shelf including things like Tl, Pb, Mn, and Ag. The tricky part is dispensing a very small and precise amount of each element into a 250 or 500mL volumetric flask to arrive at a solution where each element is exactly 50ppb. There is a quite simple calculation to find out how much 10,000ppm Sb to add to a 500mL flask to get 50 ppb. M1*V1 = M2*V2

(10,000ppm Sb)*(x mL) = (0.050ppm)*(500mL)
x = 0.0025mL or 2.5uL

In this case I would have to make an intermediate of say 10ppm and then dilute that down to 50ppb because our pipettes don't go down to 2.5uL.

Then I have your basic quality control guidelines and if the solution I made doesn't "pass", it has to be remade. One can see where it can become frustrating. And besides just calibration standards, I need to make a second source calibration check, an interference check solution, as well as all the spiking solutions used in the lab.

Thursday, June 08, 2006

On global warming from a sceptical chemist

I got into a very interesting and controversial conversation while on a trip to Chicago with a jaunt to Green Bay last week.

The topic of global warming came up from someone who believes it is happening and that something must be done about it. I made a little remark about how I was still somewhat sceptical of the whole global warming argument. And the reaction was surprisal, especially me being a scientist and everything. They went on to talk about how scientist views are being put down or hushed by Washington government. That in itself is very alarming and really requires its own post.

It gets real messy when politics get mixed in with science. You really don't know whose views are swayed by whatever. Really, what I think the problem is, I can't find information on the subject that I don't feel has been politically influenced. What I have read is mostly from science articles on the web that are conflicting. That is how it appears to me, is that scientist actually don't agree on global warming.

Instead of commenting about how I know nothing about global warming (I admit, I'm not an expert), please give me a link to some scientific literature about global warming that you believe to be the truth. I mean the facts, some evidence, you know, experimentation. I'll take a sceptical look at computer models.

By the way, I noticed I made an appearance on the Mass Spectrometry Blog.
An interesting blog by a fellow mass spectrometerist.

Cutting edge literature_, Chemistry facts_, Rants and raves_,