The determination of iridium in photographic emulsions by flow injection micro-emulsion sampling inductively coupled plasma mass spectrometry

Abstract

Flow injection micro-emulsion sampling inductively coupled plasma mass spectrometry (FI-MES-ICP-MS) was used for the determination of iridium in in-house made emulsion reference materials. The sample was stabilized by a surfactant (Triton X-100) to ensure homogeneous sampling and to prevent sedimentation. A commercially available flow injection analysis system (FIAS) was modified and easily connected to the inductively coupled plasma mass spectrometer (ICP-MS) after optimization of conditions (instrument, flow injection, concentration of surfactant, etc.). The final result is a quantitative determination of iridium in photographic emulsions with a determination limit of 0.07 μg/kg and an accuracy of 3 per cent relative standard deviations (RSD) and a precision of ±0.2 μg/kg (n = 3). The precision and accuracy of the results obtained show the applicability of this method to the determination of iridium at ultratrace levels in various photographic emulsions.