Halogen Determination in Polymeric Waste of Electrical and Electronic Equipment: Overcoming Limitations in Sample Preparation

Jussiane Silva,Paola Mello,Gabrielle Iop,Marcia Mesko,Rodrigo Pereira,Lisarb Diehl,Erico Flores

doi:10.21577/0103-5053.20190137

Abstract

Sample preparation of polymers for halogen determination requires special attention because they are difficult to bring into solution and due to the risk of analyte losses when using acid digestion. A method using microwave-induced combustion (MIC) was optimized for accurate determination of halogens in polymeric parts obtained in waste of electrical and electronic equipment. Results were compared with those by using microwave-assisted extraction (MAE) with alkaline solution and microwave-assisted wet digestion (MAWD) using concentrated nitric acid, which are common choices for sample preparation. In this particular case, the MAE method was not suitable and underestimated results were obtained, showing the necessity for the complete digestion. Even with the use of MAWD under high temperature and pressure, incomplete digestion and high acid content were obtained, which were unsuitable for analysis and resulted in poor recovery. Only by using MIC (diluted ammonia as absorbing solution) acceptable recoveries (95 to 104%) and agreement with certified values for the certified reference materials (CRMs) of polymers were obtained. Thus, a suitable method for all halogen to be determined by ion chromatography (IC) or inductively coupled plasma mass spectrometry (ICP-MS), with the exception of F, was obtained in agreement with the requirements by the Restriction of the Use of Certain Hazardous Substances (RoHS) European directive.

Highlights

The amount of generated waste of electrical and electronic equipment (WEEE) has been rapidly growing due to continuous changes in technology and the expansion of the electronics industry.[1]
Results obtained for the polymeric WEEE using 50 mmol L-1 NH3 or 0.11 mol L-1 tetramethylammonium hydroxide (TMAH) solutions, presented maximum agreement of 60% for Cl
With regard to Br quantification after microwave-assisted extraction (MAE), results were lower than the limit of quantification (LOQ) by ion chromatography (IC) (4.2 μg g-1) and inductively coupled plasma mass spectrometry (ICP-MS) (0.4 μg g-1) even though the results obtained by microwave-induced combustion (MIC) were about 12 μg g-1

Summary

Introduction

The amount of generated waste of electrical and electronic equipment (WEEE) has been rapidly growing due to continuous changes in technology and the expansion of the electronics industry.[1]. In view of the lack of CRMs of WEEE with certified values for all analytes (F, Cl, Br and I), accuracy was verified using analyte addition and CRMs provided by European Reference Materials (ERM, Geel, Belgium) of low-density polyethylene (ERM EC 680k and ERM EC 681k)

Experimental procedures

Results and Discussion

Conclusions