Here's an image:


The left side is designed to be fitted into a beaker, and it captures gas evolved during a reaction. The right side can be filled with a liquid to then react with that gas. We use it to capture ammonia from a decomposition reaction, with an indicator in the right half as part of an identification test. I'm sure it must have a name, it's a commercial piece of glassware, but the box we keep it in in the lab doesn't identify it.

  • $\begingroup$ It might be part of a Kjeldahl kit??? $\endgroup$ Oct 15, 2015 at 17:09
  • $\begingroup$ One form of a bubble trap, with valve. $\endgroup$ Aug 2, 2021 at 14:43
  • $\begingroup$ @blacksmith37 It is better if the blubberer (with all its oil inside) is a one-piece equipment only, and they don't come with a mechanical valve. The metal fork-shaped object is just a clip to keep the two pieces across the spherical joints together. As in the accepted answer, though, the clip should be rotated by 90 degrees such that the hinge of the clip is parallel to «the seam» between the two glass pieces (thus still providing a little bit of mechanical flexibility), and not (as shown in the photo) across. $\endgroup$
    – Buttonwood
    Aug 2, 2021 at 16:48

1 Answer 1


The picture shows parts of an arsine generator.

arsine generator

The apparatus can be used to determine trace amounts of arsenic by the silver diethyldithiocarbamate photometric method.

A typical method description can be found here (this is also the source of the drawing):




  • $\begingroup$ That's not what I used it for, but if that's what it's called then thank you $\endgroup$ Dec 26, 2016 at 8:26
  • 1
    $\begingroup$ I thought arsenic was detected by the Marsh test (Marshflugkörper) ;) $\endgroup$
    – Jan
    Dec 26, 2016 at 12:48
  • 1
    $\begingroup$ @Jan The methods are related; both generate arsine gas. However, the reaction with silver diethyldithiocarbamate certainly has a higher degree of selectivity than the silvery-black deposit of the Marsh test, and it also facilitates the quantitative determination. $\endgroup$
    – user7951
    Dec 26, 2016 at 13:02

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