Mastering TEM Grid Handling: Tips and Tricks for Successful Sample Preparation

[fedaykin]

I'm wondering if I can make this task easier, since I've ruined a lot of grids lately. Currently, I'm trying to use tweezers, but I lack the subtlety to grip them firmly enough without bending them.
We can't use vacuum on them since it would potentially contaminate our samples. I've thought about some sort of electrostatic device, but I think the same problem applies.

If you have any hints for using tweezers or ways to practice, I would greatly appreciate them. Thank you

 

[Moonbear]

Why would vacuum contaminate samples, especially compared to tweezers?

 

[fedaykin]

It probably wouldn't, but that's the statement I was given when I asked about them. We do test for asbestos, but if we have asbestos fibers floating around, then we have bigger problems than my ruining grids.

Oh, and we use cleaned tweezers under a laminar flow hood, so if they do introduce contaminants, it's a very small amount. We confirm this with blanks on each sample.

 

[Moonbear]

To practice with tweezers without ruining grids, you could try making paper hole punches of aluminum foil and practice picking those up. They're bigger than the grids, but flimsy and hard to grab, so might be good enough for learning a gentle, stready touch. Use your non-dominant hand to brace the wrist of your dominant hand as you pick it up. Also, control your breathing. Your hands are steadiest on a slow exhale...just don't blow the sample away! Usually, these types of things just take practice to get the knack for it.

 

[atyy]

just don't blow the sample away!

Sounds like knowledge from experience!

 

[Moonbear]

Sounds like knowledge from experience!

Not with TEM (I've never had to do it...did some SEM work, but fortunately had an amazing technician who did most of it for me). I have done it with weighing out specks of dust on a microbalance, though. I used those little hole punches of foil as weigh boats.

 

[atyy]

Not with TEM (I've never had to do it...did some SEM work, but fortunately had an amazing technician who did most of it for me). I have done it with weighing out specks of dust on a microbalance, though. I used those little hole punches of foil as weigh boats.

Good lord! Do I dare ask what the specks of dust actually were?

I'd love to learn some TEM or SEM one day though (just enough to find it cool, but not do such back breaking work for a living).

 

[Moonbear]

Good lord! Do I dare ask what the specks of dust actually were?

It was too long ago to remember what it was. It was all endocrine research, so one kind of hormone or another probably. I was one of the few people in the lab allowed to use the microbalance, because I was careful to keep fingerprints off it and didn't bend the wires on the tiny trays on the balance, but picking up those little foil weigh boats took LOT of practice.

 

[fedaykin]

Nice tips, thank you very much. I actually prepped my first viable sample today. Our acetone washer is very finicky, and it tends to blow out the form at coating if it's in a bad mood.

Hehehe, I remember one of my biology instructors getting extremely angry at a guy for picking up our microbalance and "adjusting" the spacers on the bottom. I think he changed majors for some reason afterward.