Determination of silver in nano-plastic food packaging by microwave digestion coupled with inductively coupled plasma atomic emission spectrometry or inductively coupled plasma mass spectrometry

Abstract

The detection of silver in nano-plastic food packaging by microwave digestion coupled with either inductively coupled plasma atomic emission spectrometry (ICP-AES) or inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Microwave digestion was optimised by trialling different acid mixtures. Both ICP-AES and ICP-MS showed good reproducibility, repeatability and recovery. For ICP-AES the limit of detection of the method (LODm) was 25.0 µg g⁻¹, the limit of detection of the instrument (LODi) was 30.0 ng ml⁻¹, the linear range was 0.10−10.0 µg ml⁻¹. The average recoveries for blank samples spiked with silver at 100, 250 and 500 µg g⁻¹ ranged from 82.53% to 87.60%, and the relative standard deviations (RSDs) were from 1.79% to 8.30%. For ICP-MS analysis the LODm was 0.75 µg g⁻¹, the LODi was 0.04 ng ml⁻¹, the linear range was 0.20–500.0 ng ml⁻¹, the RSDs were 2.26–4.79%, and the recoveries were 78.09–92.72% (spiked concentrations of 2.5, 5.0 and 10.0 µg g⁻¹). These results indicate that the proposed method could be employed to analyse silver in nano-plastic food packaging.

Keywords:

• metals analysis – ICP
• metals analysis – ICP/MS
• metals
• packaging additives
• plastics

Acknowledgements

This research was supported by the Colleges and Universities Research Project of Shanxi Province (Grant Number 2010102) and by China's General Administration for Quality Supervision, Inspection and Quarantine (AQSIQ) (Grant Number 2010IK160).