Last fall, C&EN ran a couple of letters that focused on the role of the syringe in the #SheriSangji case. Both called for a way to prevent a syringe plunger from coming out of the barrel. I’ve seen mention of such devices in comments around the web in the last few years, so I thought I’d take a look at what I could find:
1. The Hamilton Chaney adapter, “a device that assures repetitive and identical syringe plunger location.” The maximum volume syringe appears to be about 500 microliters, and it’s not clear how much force these adapters would resist.
2. Perfektum syringes go up to 100 mL and have a little metal clip on the end that puts pressure on the barrel. A kind source had one in their lab and took the photos to the right for me. The clips look like they wouldn’t resist much force.
3. Valco VICI precision syringes, which have a “positive rear flange plunger stop – prevents plunger from blowing out of barrel at elevated pressure.” They’re designed for chromatography. I have no idea how the plunger stop works. Readers?
4. As one of the letter-writers noted, Becton Dickinson has patents issued in the mid-90s for syringes with “a backstop device to prevent inadvertent withdrawal of a stopper or plunger rod” and “a plunger brake.” These look promising but as far as I can tell neither is available on any syringe available for purchase.
5. For the do-it-yourself crowd, an option is to drill a hole into a plastic syringe barrel and put in a screw far enough to serve as a brake on the plunger. (This procedure, of course, comes with its own set of risks.)
To sum, I really see no readily available answer for the problem. Am I missing something?