I see, so it's kind of like using a weight to calibrate your balance, fixed value.

precisely.
the mass spec is a molecular balance.

that's kind of what it looks like. so if I got this right it uses lc to seperate compounds, feeds it to the mass spec, and your feedback is the molecular weight of the analyte(s)?

That's actually pretty cool :3

That's actually exceedingly useful, too. Not just the MW of the substance but, more so, the fragmentation pattern gives good clues as to the identity of the molecule. If it's a known substance the mass spectrum can be referred to a library of spectra for confirmation (IIRC!).


Now, which Nexian can get hold of a NMR machine? That would help crack a few puzzles as well.

Is there no 'danger' that some of the sample becomes z=2 or 3 which would result in multiple peaks for same sample?

yes, and it depends on the sample (i.e. multiple charge states with larger molecules, like peptides and proteins).
small molecules are more straightforward, and the scan range is defined to isolate the respective isotopic masses.

simple math is used to determine which functional groups are dissociated within the scan range defined.
for instance, a difference of 15 between two peaks may mean a [primary] methyl group dissociated.

TY.
Got mustard here: What is m/z?
So the readout demands some interpretation, and perhaps according editing on screen?

HuZaaah! That kicks major ass. Jesus man this is quite the machine to have at home and running off solar power!

I bought that syringe pump in 2010 on e.bay for $78. it needed a new voltage selector switch, which I bought for $8 more, and installed/soldered it myself. just sold it for $202.50.

that means I got the HPLC rig for $200.

damn thats a steal. I eas looking at a syringe pump for fine filtration.

Are you ready to take samples for analysis? I'd be interested in sending you some. I was about to send one out to EcstasyData but could send it to you instead.



I can't afford there rates ($100), but would like to contribute info to the community.

https://www.dmt-nexus.me...aspx?g=posts&t=55137 a bit cheaper

Also, happy for you benz

didn't realize how busy this new job would keep me..
still, I've managed to do a lot of troubleshooting here and there (LCMS is about 50% troubleshooting, 40% analysis, 10% maintenance), and the weather is cool enough to safely operate all day.
I had a colleague weigh out standards in the lab a couple days ago, will prepare serial dilutions for tuning solution, and will tune and recalibrate either today or tomorrow. my first experiments will be cannabis extracts, as I still need to print data for some associates.

if this pans out fine, I will accept other samples. sorry for the delay, been very busy; 50+ hour weeks in the lab leave me little time in the morning, and exhausted in the evening. trying to balance spending time with the mrs is another issue...

however, I didn't get this instrument solely for tinkering, so I'll get crackalackin this weekend. no worries...sample prep and mass spec is what I do at work, and I enjoy it. so this side work is no burden. and the wife supports it

she's happy today

done.
http://r.ebay.com/OfieHo

Nice. You the man, benzyme!

thank you, good sir.

I wasn't satisfied with the sensitivity I was getting with orthogonal electrospray, and I'm running low on nitrogen.
One option was to outright buy a cylinder with nitrogen ($378 ), and keep having to get it filled (still doesn't address the sensitivity issues), or get a nanospray interface ($425, I made an offer), front dispersion, and eliminate the need for nitrogen, as well as increase sensitivity. nanospray achieves this by lowering the flowrate to low uL/min, or nL/min. this modification effectively modernizes my instrument, analysis of picograms of material is feasible.

for those who are unclear of what sensitivity means, it is a function of an acceptable signal to noise ratio, >10:1.

Damn dude. Damn.

Merry Christmas

thx

I have experience with this sort of setup. I have the option of installing a sony xc-st30 CCD camera, to observe the Taylor cone/plume. nanospray is legit for research, but not ideal for high-throughput testing (high volume).
It does save $$ in terms of solvents and lack of sheath gas. I can still test plant samples, I just need to filter everything through 0.22 um filters.

hey, 1ce and Mindillusion...we all have that mad scientist spirit in us. Keep doin' what you do.

*edit* damn..I just ordered chromeleon 6.8, so now I can program gradients, and control famos (autosampler), and a uv detector, if I get those.
I downsized the plumbing to capillary, to accommodate the lower flowrates needed for nanospray.