| Electronics > Projects, Designs, and Technical Stuff |
| Electrospray ionization - ion trap - detector |
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| ChristofferB:
Hi all! So, this is an idea that's a bit out there, I just wanted some feedback if it might be worth pursuing. I'm on an ongoing quest to construct inexpensive detectors for gas chromatography/ liquid chromatography/HPLC There's a lot of development in this area, since most common detectors for liquid chromatography (UV-VIS diode array detector, mass spectrometers, conductivity, refractive index etc.) are usually very costly and bulky. Basically, any detector that can detect peaks of dissolved molecules in a flow of liquid. Here's the idea: Make a mass spectrometer without the spectrometer. - Everything is housed in a very high vacuum chamber. Evacuated with a small turbo pump. - An electrospray ionization source to create a jet of charged particles. most of the solvent is removed here. - Maybe a simple electrostatic DC ion trap to suck away the lightest ions, acting as a mass low pass filter (might be needed to suppress solvent signal) - Faraday cup detector, femtoampere-scale amplifier, ADC. Do you see what I'm getting at? In theory, if you are certain only one compound will enter at a time you could in principle do away with the mass separation - you'd just want 'total amount ions other than solvent' as a function of time. Kinda like how a single wavelenght UV absorbance detector just detects "total amount of solutes at 255 nm" or similar. This would be mechanically much more straight forward to construct. --Chris |
| vindoline:
Not "out there" at all. I'm pretty sure that this is what we call a "total ion chromatogram" or TIC. It's a pretty good universal detector. |
| ChristofferB:
Thanks for the feedback! Yeah the output would be the same, but that's usually just a data display type from a regular chromatography-coupled MS. I don't think I've ever seen a dedicated instrument that does only that. |
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