SEALED INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY .3. OPTIMIZATION OF EXPERIMENTAL-VARIABLES

Experimental variables for a sealed inductively coupled plasma (ICP) argon discharge are investigated and optimized for the emission spectroscopic determination of arsenic and phosphorus introduced as arsine and phosphine. Important parameters include generator power, gas modifier mixture, discharge container geometry, operating pressure and operating procedure. Less important are the total gas flow rate, container preparation and construction and induction coil geometry. The optimum geometry is a 40 mm quartz sphere with a larger induction coil (almost-equal-to 45 mm in diameter). Detection limits for arsenic and phosphorus are in the low ppb range for a 950 W, 27.12 MHz argon-4% hydrogen ICP.