2. Apparatus
a. Arsine generator, scrubber, and absorption tube: See Figure 3500-As:1. Use a 200-mL
three-necked flask with a sidearm (19/ 22 or similar size female ground-glass joint) through
which the inert gas delivery tube reaching almost to the bottom of the flask is inserted; a 24/40
female ground-glass joint to carry the scrubber; and a second side arm closed with a rubber septum, or preferably by a screw cap with a hole in its top for insertion of a TFE-faced silicone
septum. Place a small magnetic stirring bar in the flask. Fit absorber tube (20 mL capacity) to the
scrubber and fill with silver diethyldithiocarbamate solution. Do not use rubber or cork stoppers
because they may absorb arsine. Clean glass equipment with concentrated nitric acid.
b. Fume hood: Use apparatus in a well-ventilated hood with flask secured on top of a
magnetic stirrer.
c. Photometric equipment:
1) Spectrophotometer, for use at 520 nm.
2) Filter photometer, with green filter having a maximum transmittance in the 500- to
540-nm range.
3) Cells, for spectrophotometer or filter photometer, 1-cm, clean, dry, and each equipped
with a tightly fitting cover (TFE stopper) to prevent chloroform evaporation.
đang được dịch, vui lòng đợi..
