Trap Tube Research Articles

Trapping Low Levels of Methyl Bromide in Air or as Residues at Ambient and Lower Temperatures for Gas Chromatography

Abstract Methyl bromide in air was analyzed by direct injection onto a trapping tube filled with Tenax GC and operated at 25 or 0°C. Methyl bromide amounts as low as 35 ng could be determined. Methyl bromide flushed from flasks and collected in cold traps before injection onto the trapping tube showed recoveries of 99% for 30 ng in a 60 L sample. This gas chromatographic method was also used to determine methyl bromide desorption from fumigated wheat; 0.3 ppb (10-9 g) was desorbed in 24 h from 1 g wheat aerated for 30 days.

A Single-Crystal Orienter for the Philips Wide-Range Goniometer

AbstractA single-crystal orienter for the Philips -wide-range goniometer is described. The orienter has a large (3.562 in.) carriage radius for convenient access. The carriage rides on twin V-ways ground accurate to ±0.0002 in. Carriage settings arid spindje settings can be made to 1′. The spindle mounts a standard goniometer head and translates to center the head arcs. An accessory collimator, beam trap, and scatter tube are described.