We measure latex particles down to 190nm with our Elite on 10 to 15 mW aircooled laser power. Below 300nm we use side scatter triggering as even our modified forward scatter cuts of at 300nm. We filter the sheath "on line" in front of the flow cell. We could probably get below that by cleaning up the sheath further as the scatter background signal goes down if we stop the sheath flow. If I remember right from Howard the theoretical limit is around 80nm but I don't remember at what wavelength. Regarding the display you have to look at two parameter plots of forward versus side scatter as it allows you to remove some of the noise you get for example from protein precipitates micro-airbubbles and other things starting to interfere at this level. Main secret seems to be a very clean sheath and flow cell and a good alignment of the system. Regards Gerhard -----Original Message----- From: Ryan Duggan [mailto:rcduggan@midway.uchicago.edu] Sent: 06 August 2002 18:10 To: cyto-inbox Subject: Detection of Nanoparticles Hello All, Is it possible to detect particles on the order of 0.1um to 0.3um using standard flow cytometers? I've done some preliminary trials, and haven't had much luck (too much background noise, not enough FSC signal). If anyone has had any experience with this size particles, I'd appreciate hearing from you. The instruments I have to use are; FACScan, FACSCalibur, LSR, FACStar Plus, and MoFlo. Also, If there are feasible modifications I can make to any of these instruments to be able to see this size particles, that would be helpful. All ideas are welcome. I've search the archives and found a few similar questions, but no replies. Thank You, Ryan _____________________________________________________________________ Disclaimer This email and any files transmitted with it, is confidential and intended solely for the use of the individual to whom it was addressed. Unipath monitors emails to ensure its' systems operate effectively and to minimise the risk of viruses. Whilst it has taken reasonable steps to scan this email, it does not accept liability for any virus that may be contained in it. _____________________________________________________________________
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