Method for detecting heavy metals in plastics

Abstract

The invention discloses a method for detecting heavy metals in plastics. The method comprises the following steps: S1. putting the plastics to be detected in an airtight container filled with an organic solvent, and carrying out ultrasonic oscillation in a water bath to dissolve the plastics, thus obtaining a plastic dissolution solution; S2. adding dilute nitric acid to the plastic dissolution solution, carrying out ultrasonic oscillation at room temperature, and carrying out filtration, washing and constant volume achievement to extract heavy metals in the plastic dissolution solution, thus obtaining a solution to be detected, containing the organic solvent; S3. qualitatively and quantitatively analyzing the heavy metals in the solution to be detected by adopting an inductively coupled plasma optical emission spectrometer (ICP-OES). The method has the beneficial effects that by utilizing the characteristic that the plastics have better solubility in the organic solvent, the plastics are dissolved by using the proper organic solvent, and then the heavy metals in the plastics are extracted to form the solution to be detected, containing the organic solvent; then the heavy metals dissolved in the organic solvent are qualitatively and quantitatively analyzed by adopting the ICP-OES. The method has the advantages of simple and fast operating process, mild reaction conditions, accuracy in detection, high recovery rate and good stability and is suitable for mass treatment.

Description

technical field [0001] The invention relates to a heavy metal detection method, in particular to a heavy metal detection method in plastics. Background technique [0002] Due to the wide range of raw material sources, various types, easy processing, low processing cost, and excellent performance, plastics have become an indispensable class of important materials in various industries. Plastic products are widely used in food packaging, building materials, children's toys, medical equipment, electronic appliances, etc. Due to the widespread use of plastics, the requirements for toxic additives in plastics are quite strict. [0003] Looking at the current standards and detection methods, the determination of heavy metal elements such as lead and cadmium in plastics is generally carried out by electrothermal digestion or microwave digestion with acid as the medium, and then using AAS (atomic absorption spectrometer), ICP-OES (inductively coupled plasma Mass emission spectrome...

AI Technical Summary

Problems solved by technology

However, the traditional plastic digestion has the following defects: electrothermal digestion requires strong acid and high temperature (above 200°C); open digestion has the risk of cross-contamination; digestion takes a long time

Due to the introduction of organic solvents into ICP, complex molecular bands and continuous spectra will be produced, and at the same time, the inverse impedance of ICP will be changed, thereby changing the impedance matching state of its high-frequency generator, causing ICP to be unstable or even completely extinguished, and it is also easy to burn in the torch The formation of carbon particles in the mouth affects the stability of ICP, so it is generally believed that the presence of organic solvents reduces the analytical performance of ICP-OES

At present, the application of ICP-OES to the determination of heavy metal elements in volatile organic solvents is seldom, and further research and application are still needed.

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