GB/T 42240-2022Nanotechnology—Measurement of metallic impurities in graphene powder—Inductively coupled plasma mass spectrometry (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents" drafting.

Introduction

Graphene powder is currently the main form of graphene products in my country, and has been used in new energy batteries, thermal management, heavy-duty coatings and other industrial fields.

Preliminary realization of large-scale application. Graphene powder can be produced through different production processes such as mechanical exfoliation, reduction oxidation, intercalation dissociation, small molecule synthesis, etc. preparation. Due to differences in production processes, production equipment, raw materials, etc., the ratio of metal impurity elements contained in graphene powders produced by different manufacturers There are also significant differences in species and content. Metal impurities will directly affect the application performance of graphene powder, graphene application technology development and production The development of the industry urgently needs to establish a standardized analytical test method for accurate and reliable detection of metal impurities in graphene powder.

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technology can realize the simultaneous rapid trace quantitative detection of various inorganic elements and isotopes It has wide dynamic linear range and high sensitivity. The development of a quantitative test method for metal impurities in graphene powder based on ICP-MS technology is under test The test is technically feasible, but three problems need to be solved. (1) Sample processing. the crystal structure of graphene is composed of carbon atoms covalently bonded by pi-pi The hexagonal close-packed honeycomb formed by the combination of graphene and chemical bonds is difficult to be opened, and the sample to be tested by ICP-MS technology should be a solution, so it is necessary to mix graphene The powder is completely digested. The "high temperature ashing" sample processing method is commonly used in the testing of carbon materials such as graphite, but due to the low apparent density of graphene, In the process of heating and ashing, it is easy to drift and inevitably introduce large errors; concentrated sulfur that has a strong digestion effect on graphene powder Acid, perchloric acid, hydrogen peroxide, etc. may produce obvious polyatomic ion interference during the test and affect the accuracy of the test results, or under high temperature and high pressure There is a high risk of explosion and explosion under airtight conditions, so it is first necessary to develop an applicable and scalable sample processing method. (2) Multi-element standard calibration Curve establishment and quantitative testing. the quantitative testing of inorganic impurities using ICP-MS technology requires the establishment of standard calibration curves for the measured elements, and There are more than 20 types of metal impurity elements contained in industrialized graphene powder, and the content of each element has a very wide distribution range, ranging from a few micrograms to Every kilogram (µg/kg) to thousands of milligrams per kilogram (mg/kg), so it is necessary to consider how to establish a standard calibration curve for each element to be measured;

In addition, for elements that are susceptible to environmental influences, spectral line interference, and matrix interference, it is possible to establish appropriate methods or select appropriate test modes to Get the most accurate and reliable test results possible. (3) Recovery rate of standard addition. due to the complex composition of the graphene powder measurement sample and the influence factors of the test If there are many, the recovery rate of standard addition can be used to verify the reliability of the test analysis method. This document provides solutions to the above three problems and establishes Standardized quantitative test and analysis method for metal impurities in graphene powder.

Determination of Metallic Impurities in Nanotechnology Graphene Powders Inductively Coupled Plasma Mass Spectrometry Warning. The reagents (nitric acid, hydrofluoric acid) used for sample digestion in this document are highly oxidizing and corrosive, and the operation process must be strictly Comply with the experimental conditions and instrument operating instructions, pay attention to safety protection.

1 Scope

This document describes a method for the determination of metallic impurities in graphene powders by inductively coupled plasma mass spectrometry.

This document is applicable to the determination of metal impurities in graphene powder. Other carbon-based nanomaterials, such as carbon nanotubes, carbon fibers, porous carbon, etc.

The determination of contained metal impurities shall be carried out according to the reference.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB 5009.268 National food safety standard Determination of multi-elements in food

3 Terms and Definitions

The following terms and definitions apply to this document.