How to make a 1000 fold dilution

Making dilutions is an everyday thing when analyzing environmental samples. It's either diluting salt water samples by 10 because they have such a high ion content they suppress the plasma and cause internal standards to drop too low or diluting sediment samples because it takes more acid to digest them than is in the calibration standards.



Before entering into environmental analytical chemistry I would say to make a 1000 fold dilution, add 1000mL to 1 mL of what you're trying to dilute. But that's wrong, you add 999mL to 1mL of what you're trying to dilute. Reason is, it's already diluted once. If you start with pure copper for example, and stuck it in a beaker, then you would have to add 1000mL to dilute it 1000 fold. But if the copper is already dissolved in 1mL, then you would have to add 999mL to dilute to 1000 fold. I'm pretty sure you typically don't see pure metals, sitting around an environmental chemistry laboratory waiting to be dissolved into standards. It's much easier and cost effective to buy the metals already dissolved in water in nice, guaranteed concentrations, like 10,000ppm.

I can grow orchids --->

How to get motivated for work

Someone asked me the other day how I got motivated for work. It didn't come out of the blue, we've been having some serious mass spec problems we just can't figure out. Turns out now, the technician can't really figure it out either. I replied I have to get paid, just kind of as a joke. I didn't really have time to think about it.

Maybe it's actually competition. Not just from people around me in the present, but people in the past. Stories of old chemists discovering things, having moments of clearity, and thinking "eureka!" actually motivates me. Maybe if I don't give in to working and feeling like a slave I'll get better at what I'm doing. The only way to solve a problem is to see the answer. It's hard to keep an open vision and look at things in a new way when you give into the stress of work problems.

So, to get motivated for work, seek inspiration from the past.

DARTs and MS

I'm sure all the mass spec people have heard about this before because it is so cool and also one year old news. It's a new ionization method called DART (direct analysis in real time) invented by Robert B. Cody of JEOL USA and James A. Laramee of EAI Corp. It is a sample introduction system that can be coupled to a mass spectrometer, currently only coupled to a MS by JEOL.
The major difference here, compared to other mass specs, is the sample inlet is at atmospheric pressure. You can hold an object, such as an orange, up in front of the sample cone and get a reading of masses detected and find fungicides.

This technique works by applying an electrical potential to a gas (N2 or H2) to form a plasma that interacts with the sample and the atmosphere.

It took me a minute to picture the instrument layout in my head, I couldn't, so I went to the website. The path of the ion: First, gas is fed in, a plasma is formed, then the instrument opens up to the atmosphere. So, the open region is between the plasma torch and the sample cone. Then, the rest of the mass spec, the one they use happens to be a time-of-flight.