Iron pentacarbonyl determination in carbon monoxide

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), concentrations were observed over a 1-year period in two different carbon steel cylinders containing CO. (C) 1999 Elsevier Science B.V. All rights reserved.