Open flames are not a thing in lab settings. It's too damn dangerous, would interfere with positive/negative pressure spaces, and sterility is now maintained with sterile single use items.

[–] Deconceptualist@leminal.space 5 points 2 hours ago* (last edited 2 hours ago)

Burners are definitely still used in chemistry, but primarily in teaching labs and other situations when you don't require fine precision and just need to bring a solution to a boil, e.g. at the bottom of a distillation column.

But yeah reusable tools are generally sterilized in an autoclave or with UV. Especially something like a quartz cuvette that you wouldn't want soot on.