Iron pentacarbonyl determination in carbon monoxide

摘要

Iron pentacarbonyl, Fe(CO)_5, was previously employed to calibrate the sealed inductively coupled plasma (SICP) for Fe in a 50% chlorine discharge. The same technique is used to determine Fe as Fe(CO)_5, one of the most important metallic compound impurities present, in carbon monoxide cylinders. Iron concentrations in various CO cylinders were determined directly by SICP in 30% (v / v) CO. Operating parameters including incident power and maximum tolerable CO and Cl_2 concentrations in the discharge were optimized. The detection limit for Fe(CO)_5 in CO was 0.18 #mu#l l~(-1) (172 ng absolute). Statistically similar results were obtained when Fe(CO)_5 content was determined by FTIR and SICP-AES. Two- and sevenfold increases in Fe(CO)_5 concentrations were observed over a 1-year period in two different carbon steel cylinders containing CO.