Method for the Determination of Cu(II), Ni(II), Co(II), Fe(II), and Pd(II) at ppb/subppb Levels by Ion Chromatography

Abstract
A method for the determination of Cu(II), Ni(II), Zn(II), Co(II), Fe(II), and Pd(II) at ppb/subppb levels by ion chromatography was developed, improving a previous work of the same authors. In order to lower the detection limits, the direct injection of a large sample volume (5 mL) and 4‐(2‐pyridylazo) resorcinol solution at pH 6, with hexadecylpyridinium chloride as the post‐column reagent were used. The obtained calibration curves were linear (for each metal R2≥0.99) with good reproducibility; the detection limits for Cu(II), Ni(II), Zn(II), Co(II), Fe(II), and Pd(II) were 1.1, 0.46, 39, 0.18, 4.5, and 1.7 ppb, respectively.