A Very Inexpensive NMR Tube Washer Although NMR tube washers are commercially available, they are not only expensive (-$40-$50), but also suffer from a high mortality rate hecause of their inherently fragile structure. My graduate students and I have been using the same NMR tube washer for the Last eight years, on which I invested Less than $0.50 (probably $1 now). The apparatus is very simple in design and self-explanatory (see figure). Bore Aof an internal diameter (i.d.) of 2 mmmakesair-tight contact withthe polyethylene tube (2 mm id.), and bore B (4 mm id.) provides air-tight contact with the open end of an inverted 5-mm NMR tube. The present apparatus enjoys all the advantages that are offered by commercially available NMR tube washers; furthermore, being made out of arubher stopper and a piece of palyethylene tube, it is simply unbreakable. Change of wash solvent is s i m.~.l vachieved bv. dinnine tube from one solvent to another. . . . the oolvethvlene . It ra clear rhnr urr of rhe present device provides at) increased life expectancy for healthy NMR tubrs. Also, since the yulyethylene tube can more freely in hore B, NhlR tulles thnt h e w lo41 an acceptable amount uf their length (h
