A chromogenic column for determining phosphine in air

Abstract

AbstractA 1% solution of mercuric chloride in 0.1% cresol red in ethanol, impregnated onto celite and filled into a glass tube [17.8 cm × 0.2 cm (i.d.)] could accurately determine even 0.06 μg phosphine in air. The samples were injected quickly through a rubber septum cap on the glass tubes under low suction. A red coloured band developed instantaneously, the length being proportional to the concentration of phosphine. A calibration curve was prepared with known concentrations of phosphine. The concentrations present in a fumigation chamber were determined and compared with concurrent chemical analysis. There was close agreement between the two methods.A 1:3 and 1:6 mixture of phosphine and ammonia produced two bands, a yellow ammonia band preceding the red phosphine band. However, ammonia interfered with the proper development of the phosphine band.