Anal. Chem. 1981, 53, 944
944
One-Piece Arsine Collection Apparatus R. J. Everson Animal Disease Diagnostic Laboratory, Purdue University, West Lafayetfe, Indiana 47907
The official method of the AOAC (1)for the determination of arsenic in feeds calls for the evolution and collection of arsine gas in the final steps of the procedure. While glassware is commercially available (2)to facilitate the collection of the arsine, it has a few disadvantages. The apparatus has two sections which are connected through a ball and socket joint. If a tight seal is not maintained, arsine gas can be lost during its evolution. The capillary tubing leading into the tube holding the absorbing solution has a bore which produces large bubbles. An apparatus was desired which would be one part and produce tiny bubbles in the absorbing solution to increase the efficiency of absorption. Figure 1shows such a device which is made by using a standard 15-mL centrifuge tube, 8 mm 0.d. glass tubing (to hold the lead acetate impregnated glass wool), and 5 mm 0.d. (approximately 1mm bore) capillary tubing. The 8-mm tubing is connected to the 125-mL Erlenmeyer flask with a one-hole rubber stopper. Care should be taken when inserting the 8-mm tubing through the hole in the stopper. The fit must be snug to prevent the escape of arsine. The stopper should also fit the flask tightly.
LITERATURE CITED (1) Horwitz, W., Ed. "Official Methods of Analysis", 12th ed.; AOAC: Washington, DC, 1975; Section 42.005. (2) Fisher Scientific Co., 1981 catalog, Pittsburgh, PA, p 14.
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Figure 1. A one-piece arsine collection apparatus.
R~~~~~~~for review january 26, 1981, Accepted February 25, 1981.
0003-2700/81/0353-0944$01.25/00 1981 American Chemical Society
