Study Of The Analytical Testing And The Enviornmental Assessment Of Hazardous Substances In Electronics

Firstly, this study discusses a test solution to comply with the EU Directive "Restriction of Hazardous Substances in Electronic and Electrical Equipments" (RoHS). Secondly, it presents some applications of four analytical techniques to detect hazardous substances in electronics. Thirdly, it gives a quantitative environmental assessment of metallic elements in mobile phones using the toxicity potential indicator (TPI).For RoHS compliance, the test solution is established to be an Energy Dispersive X-Ray Fluorescence (EDXRF) screening followed by sophisticated instrumental analyses. If the screening data are in the scope of legal limit with a 30-50% margin of safety, further precise analyses are recommended. With the help of microwave digestion using strong acid, alkali, or organic solutions, the Inductive Coupled Plasma-Optical Emission Spectrometry (ICP-OES) is suitable for the determination of Cd, Pb and Hg, the Gas Chromatography-Mass Spectrometry (GC-MS) for polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE), and the Double Beam Ultraviolet/Visible Spectrophotometry (DBU/VS) for Cr⁶⁺.With these analytical techniques, the relative standard deviation (RSD) of test data is less than 5% for Cd, Pb, Hg and Cr⁶⁺, and the RSD for PBB and PBDE is less than 1%, which suggests a high precision with good stability. The recovery rate of Cd, Pb, Hg , Cr⁶⁺, and ten BBs (from Mono-BB to Deca-BB) lies in 90-110%, which indicates a high accuracy with minimized contamination and gross loss during the sample preparation. The limit of detection and limit of quantification are found to be at the order of ng/g andμg/g, respectively, which means a high sensitivity with reliable performance. In addition, optimal processing parameters for detecting Cr⁶⁺ using the DBU/VS are obtained.There are more than 20 metallic elements in mobile phones, which make up 35-40% of the total mass. The TPI of Pb is calculated to be 20.8 mg^-1. It is confirmed that 12 highly hazardous elements (>12TPI/mg) present in the mobile phones, which make them a potential threat to the environment if substantial numbers of phones are improperly treated at the end of their lives. The average TPI for two mobile phones in this study is 4.1 mg^-1 and 4.5 mg^-1, respectively. As referred to Pb, the total impact of metals from them is equal to the effect of releasing 6.14 g and 12.28 g Pb, respectively, into the environment under a worst-case scenario. The relatively new model of mobile phones is more eco-effective than the old one, which is not due to a reduction in the type of hazardous metal, but rather to a significant miniaturization of the package with less mass.