Multivariate optimization for the development of a sample preparation procedure and evaluation of trace elements in plastic toys

Abstract

Background

Due to the rigidity and resistance caused by formation of bonds between polymer chains, plastic toys are complex matrices.

Objective

This study was Doehlert design for reagent optimization proportions employing microwave-assisted digestion of plastic toy samples. Inductively coupled plasma optical emission spectrometry (ICP OES) was applied to determine the concentration of Cd, Co, Cr, Cu, Mn, Ni, and Pb. Arsenic and Sb concentrations were determined employing hydride generation atomic fluorescence spectrometry (HG-AFS) coupled with a multisyringe flow injection analysis (MSFIA) system.

Methods

Plastic toy samples of different colors and shapes were analyzed. Accuracy and precision were measured through analysis of certified reference material of Loamy Clay 1 (CRM 052 – Trace Metals - Loamy Clay 1) along with addition and recovery tests.

Results

The limits of quantification varied between 0.03 (Cd and Mn) and 0.70 mg kg⁻¹ (Sb). All plastic toy samples exhibited concentrations of As, Cd, Cr, Pb, and Sb within the maximum limits established by Brazilian Institute of Metrology, Quality, and Technology (Instituto Nacional de Metrologia, Qualidade e Tecnologia – INMETRO). The concentrations of Co, Cu, Mn, and Ni were below the maximum limits of the Brazilian safety legislation. However, the concentration of Pb in a toy sample was higher than allowed according to European legislation (2009/48/CE), while other elemental concentrations followed European legislation.

Conclusion

The analytical capacity for spectroanalytical techniques as such ICP OES and MAFIA-HG-AFS was adequate in determining trace elements (Co, Cu, and Mn) and potentially toxic (As, Cd, Cr, Sb, Ni and Pb). It showed an excellent application for the analysis of plastic toys.