CN115407013B - Determination method of decabromodiphenyl oxide flame retardant in electronic and electric products - Google Patents

Abstract

The invention discloses a method for measuring decabromodiphenyl oxide flame retardant in electronic and electric products, wherein the novel micro sample pretreatment technology related to the method is a pretreatment technology which has the advantages of less operation steps, less time consumption and low cost, does not use an organic solvent, takes a glass tube as a reactor device, and overcomes the defects of complicated operation, long time consumption and certain danger caused by ignition and oxygenation in the traditional pretreatment method; secondly, the method can degrade decabromodiphenyl ether at a lower temperature, and the efficiency of degrading and debrominating the decabromodiphenyl ether at a low temperature is improved by combining with Fenton reaction; the analysis method has the characteristics of high sensitivity, simplicity, convenience and low cost.

Description

Determination of Decabromodiphenyl Ether Flame Retardant in Electrical and Electronic Products

Technical Field

The invention relates to a method for determining a decabromodiphenyl ether flame retardant in electronic and electrical products by combining a novel micro-sample pre-treatment technology with an ion chromatography method.

Background technique

Brominated flame retardants (BFRs) are additives that can prevent plastics and other polymer materials from being ignited or inhibit the spread of flames. They are widely used in electronic products, automobiles, polyurethane foams, and textiles. Brominated flame retardants are the most consumed organic flame retardants. There are many types of industrial brominated flame retardants, mainly polybrominated biphenyls, polybrominated diphenyl ethers, brominated bisphenol A, brominated polymers, brominated phthalic anhydride, brominated phenols, brominated polyols and other brominated flame retardants. Among them, polybrominated diphenyl ethers are the most widely used compared to other types of flame retardants due to their excellent flame retardant effect and low price. They are widely used in circuit boards, textiles, building materials, toys, and daily necessities. For example, decabromodiphenyl ether has a very wide range of applications due to its good thermal stability, non-corrosiveness to molds during injection molding, low toxicity, and no pollution to the environment. However, electronic and electrical products containing this type of brominated flame retardants will release toxic and corrosive hydrogen bromide gas during combustion, which will cause certain damage to the human body and the environment. According to the requirements of the international standard IEC 61249-2-21, the halogen-free standard refers to the bromine and chlorine content being less than 900 mg/kg respectively, and the total content of bromine and chlorine being less than 1500 mg/kg. Therefore, it is necessary to establish a method to analyze the bromine content in electronic and electrical products to achieve the quality monitoring of brominated flame retardant-decabromodiphenyl ether in electronic and electrical products.

As a rapid separation and highly sensitive test method, ion chromatography is widely used in all walks of life. Ion chromatography is used to determine the content of elements in compounds. The main pretreatment methods include high-temperature hydrolysis, oxygen bottle (bomb) combustion, high-temperature roasting, alkali fusion, catalytic digestion and ultraviolet decomposition. Compared with other methods, the oxygen bottle (bomb) combustion method is low in cost and uses glass instruments that are readily available in most analytical laboratories. Almost all organic matrices can be decomposed during the combustion process, and interference can be avoided in subsequent analytical determinations. It is widely used in the determination of the content of organic bromine, chlorine, phosphorus and sulfur elements. However, the operation of the oxygen bottle (bomb) combustion method is relatively cumbersome and time-consuming. Only one sample is processed at a time, and each time, oxygen needs to be filled into the oxygen bottle (bomb) and ignited, which is somewhat dangerous. At present, China's national standard GB/T 37861-2019 provides an oxygen bomb combustion-ion chromatography method for the determination of halogen content in electronic and electrical products. However, considering the shortcomings of the oxygen bomb combustion mentioned above, it is necessary to design a new micro-sample pretreatment technology to overcome these problems, and combine ion chromatography to determine the bromine content in electronic and electrical products, so as to analyze and detect the content of brominated flame retardant-decabromodiphenyl ether therein.

Summary of the invention

In view of the deficiencies in the prior art, the present invention provides a qualitative and quantitative analysis method for decabromodiphenyl ether flame retardant in electronic and electrical products.

The technical solution of the present invention is as follows:

A method for determining decabromodiphenyl ether flame retardant in electronic and electrical products comprises the following steps:

(1) Sample pretreatment

The sample to be tested is placed in a glass tube with one end sealed and the other end open, and then deionized water A is added. After the open end of the glass tube is sealed, it is placed in a high-temperature furnace and maintained at 300° C. for 30 minutes. After that, it is taken out and allowed to stand and cool to room temperature. The outer surface of the glass tube is washed with deionized water B, wiped clean, and dried. After the glass tube is cut, it is placed in a headspace bottle. Deionized water C, 50mmol/L ferrous sulfate solution, and 30% (volume fraction) hydrogen peroxide solution are added to the headspace bottle. After sealing, it is reacted at 40° C. for 30 minutes, and then allowed to stand and cool to room temperature. The headspace bottle is rinsed with deionized water D, and then the liquid in the headspace bottle is transferred to a 10mL volumetric flask, and the volume is fixed with deionized water E, shaken well, and filtered through a 0.20μm disposable sample filter (Hippocampus) to obtain a sample solution for standby use.

The sample to be tested was pretreated as follows before use: the sample to be tested was washed with deionized water, left to dry overnight at room temperature, and then cut into 1-3 mm pieces for later use;

The glass tube has an outer diameter of 1.4 mm, an inner diameter of 1.3 mm, and a length of 80 mm;

The headspace bottle is a 10 mL transparent round bottom headspace sample bottle with an 18 mm threaded mouth;

The dosages of the sample to be tested, deionized water A, deionized water C, 50mmol/L ferrous sulfate solution, and 30% hydrogen peroxide solution are 1mg, 20μL, 400μL, 100μL, and 100μL, respectively;

The purpose of cutting the glass tube and placing it in the headspace bottle is to enable a part of the pyrolysis products on the wall of the glass tube to contact and react with the subsequent ferrous sulfate solution and hydrogen peroxide solution, thereby increasing the reaction contact area; the specific length of the glass tube cutting is irregular, and is about 2 to 5 mm; the glass fragments will eventually be filtered out by a disposable sample filter;

The deionized water A to deionized water E have no special meanings, and are marked as A, B, C, D, and E only to distinguish the deionized water used in different operation steps;

(2) Sample injection

The sample solution prepared in step (1) is injected into an ion chromatograph ICS-600 for determination and analysis to obtain a sample spectrum;

ICS-600 instrument conditions:

Suppressor type: ASRS-4mm; Suppression current: 25mA; Eluent: 10mmol/L KOH solution; Elution procedure: 10mmol/L KOH solution isocratic elution for 15min; Ion chromatography column, guard column: AS18, AG18; Pressure range: 200-3000psi; Mobile phase flow rate: 1.0mL/min; Chromatographic column temperature: 30℃;

(3) Establish a single-point calibration curve

Weigh the decabromodiphenyl ether standard, perform pretreatment according to the method of step (1) (i.e., replace the sample to be tested with the decabromodiphenyl ether standard), and obtain a calibration working solution; inject the calibration working solution into an ion chromatograph ICS-600 for determination and analysis (the instrument conditions are the same as those in step (2)), and obtain a standard spectrum; draw a calibration curve (the curve passes through the origin) with the peak area of bromide ions in the spectrum as the ordinate and the mass of the decabromodiphenyl ether standard as the abscissa;

The weight of the decabromodiphenyl ether standard is 0.50 mg;

(4) Actual sample test results

Substitute the peak area of bromide ions in the sample spectrum obtained in step (2) into the calibration curve established in step (3) to calculate the content of decabromodiphenyl ether in the actual sample.

Compared with the prior art, the advantages of the present invention are mainly reflected in:

The novel micro-sample pretreatment technology provided by the present invention is a pretreatment technology with few operation steps, less time consumption, low cost, and no use of organic solvents. The glass tube is used as a reactor device to overcome the shortcomings of the traditional pretreatment method, which is cumbersome and time-consuming, and the disadvantages of ignition and oxygenation having certain dangers; secondly, the method can degrade decabromodiphenyl ether at a relatively low temperature, and by combining with the Fenton reaction (hydrogen peroxide reacts with divalent iron ions), the efficiency of low-temperature degradation and debromination of decabromodiphenyl ether is improved. This method improves the sensitivity of the analytical method and is a simple, convenient, and low-cost method for determining decabromodiphenyl ether flame retardants in electronic and electrical products.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1: Schematic diagram of the micro-sample pretreatment technology of the present invention.

Figure 2: Bromide ion chromatogram; wherein a is the bromide ion chromatogram of the decabromodiphenyl ether standard, obtained according to steps (2-3) of Example 1; b is the 10 mg/L bromide ion chromatogram, obtained by measuring with a 10 mg/L NaBr solution.

Figure 3: Single point calibration curve for decabromodiphenyl ether.

Figure 4: Ion chromatogram of the reaction product of actual sample a.

Detailed ways

The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

Example 1

(1) Instruments and reagents

Ion chromatograph (Thermo Scientific, ICS-600), decabromodiphenyl ether powder standard (purity 98%), NaBr standard.

(2) Experimental methods

(2-1) Pre-treatment

The actual sample was washed with deionized water, left to dry overnight at room temperature, and then cut into 1-3mm fragments for later use. Take 1mg of the actual sample after treatment, put it into a glass tube, and then add 20μL of deionized water. Place the sealed section of the glass tube downward on the glass tube holder, and burn it with a flame about 1cm away from the open end of the glass tube to make it melt and break naturally, completing the sealing of the end. Then place it in the column oven of the Fuli gas chromatograph and keep it at 300℃ for 30min. Then take it out and let it stand and cool. Wash the outer surface of the glass tube with deionized water, rinse it two or three times, wipe it clean, and dry it. Use a ceramic sheet to cut the glass tube into a certain length of glass tube and put it into the headspace bottle, then add 400μL of deionized water, 100μL of 50mmol/L ferrous sulfate solution, and 100μL of 30% hydrogen peroxide solution. After sealing, react at 40℃ for 30min. Then take it out and let it stand and cool. Use a microinjection needle to draw deionized water to rinse the headspace bottle. Repeat this operation several times, transfer the reaction solution in the headspace bottle to a 10mL volumetric flask, then make up to volume with deionized water, shake well, and pass through a 0.20μm disposable sample filter (Hippocampus) for use.

(2-2) Sample injection

The solution obtained after the pretreatment in step (2-1) was sampled and analyzed on an ion chromatograph ICS-600:

ICS-600 instrument conditions:

Suppressor type: ASRS-4mm; suppression current: 25mA; eluent concentration: 10mmol/L KOH; elution procedure: isocratic elution with 10mmol KOH for 15min; ion chromatography analysis column, guard column: AS18; AG18; pressure range: 200-3000psi; mobile phase flow rate: 1.0mL/min; column temperature: 30℃.

(2-3) Establishing a standard curve

The calibration curve here is composed of a mass, 0.50 mg of decabromodiphenyl ether. First, 0.50 mg of decabromodiphenyl ether powder standard is weighed, and three groups are weighed in parallel. The sample is placed in a glass tube and pre-treated according to the pre-treatment method described in step (1) (i.e., the actual sample in step (1) is replaced by the decabromodiphenyl ether powder standard). The obtained standard solution is subjected to ion chromatography analysis under the instrument conditions in step (2) to obtain a bromide ion spectrum. The calibration curve (the curve passes through the origin) is drawn with the mass of the decabromodiphenyl ether standard in the calibration working solution as the horizontal coordinate and the area of bromide ions in the spectrum as the vertical coordinate.

(3) Results and discussion

The experiment established a calibration curve for decabromodiphenyl ether, and the results are shown in Figure 3, with an RSD of less than 7.46%. By measuring the bromine content in the sample, the content of decabromodiphenyl ether was deduced. Here, an actual sample connector was measured, and the results are shown in Table 1, with an RSD of less than 25.6%. Therefore, it is believed that this method has good accuracy and can be used to determine decabromodiphenyl ether in actual samples.

Table 1 Determination results of decabromodiphenyl ether in actual samples

Secondly, the debromination efficiency of this method was investigated. The theoretical total bromine content of 1 mg of decabromodiphenyl ether (purity 98%) is 0.8160 mg, the actual measured bromine content is 0.2190 mg, and the debromination efficiency is 26.91%. The calculation formula is as follows:

The method of using micro-reaction pretreatment technology combined with ion chromatography to determine decabromodiphenyl ether in electronic and electrical products is simple and efficient. It is based on the principle that decabromodiphenyl ether will degrade to produce hydrogen bromide gas at a certain temperature, and combine with the Fenton reaction on the basis of degradation to oxidize the remaining substances to release more hydrogen bromide. We can determine the bromine in the solution of the sample after the reaction is completed, and calculate the content of decabromodiphenyl ether in the sample by single-point quantitative method. Therefore, it can be considered that this simple, fast and efficient method is suitable for the determination of decabromodiphenyl ether in electronic and electrical products.

Claims (4)

1. A method for determining the content of decabromodiphenyl ether flame retardant in electronic and electrical products, characterized in that the method comprises the following steps: (1) Sample pretreatment Put the sample to be tested into a glass tube with one end sealed and the other end open, then add deionized water A, seal the open end of the glass tube and place it in a high-temperature furnace, keep it at 300°C for 30 minutes, then take it out and let it stand and cool to room temperature, wash the outer surface of the glass tube with deionized water B, wipe it clean, and dry it; cut the glass tube and put it into a headspace bottle, add deionized water C, 50mmol/L ferrous sulfate solution, and 30% hydrogen peroxide solution into the headspace bottle, seal it and react at 40°C for 30 minutes, then let it stand and cool to room temperature, rinse the headspace bottle with deionized water D, then transfer the liquid in the headspace bottle to a 10mL volumetric flask, make up to volume with deionized water E, shake well, pass through a 0.20μm disposable sample filter to obtain a sample solution for standby use; (2) Sample injection The sample solution prepared in step (1) is injected into an ion chromatograph ICS-600 for determination and analysis to obtain a sample spectrum; (3) Establish a single-point calibration curve Weigh a decabromodiphenyl ether standard, perform pretreatment according to the method of step (1), and obtain a calibration working solution; inject the calibration working solution into an ion chromatograph ICS-600 for determination and analysis, and obtain a standard spectrum; draw a calibration curve with the peak area of bromide ions in the spectrum as the ordinate and the mass of the decabromodiphenyl ether standard as the abscissa; (4) Actual sample test results Substituting the peak area of bromide ions in the sample spectrum obtained in step (2) into the calibration curve established in step (3) to calculate the content of decabromodiphenyl ether in the actual sample; In the above step (2) or (3), the ICS-600 instrument conditions are as follows: suppressor type: ASRS-4mm; suppression current: 25mA; eluent: 10mmol/L KOH solution; elution procedure: isocratic elution with 10mmol/L KOH solution for 15min; ion chromatography column, guard column: AS18, AG18; pressure range: 200-3000psi; mobile phase flow rate: 1.0mL/min; column temperature: 30°C. 2. The method for determining the flame retardant of decabromodiphenyl ether in electronic and electrical products according to claim 1, characterized in that in step (1), the sample to be tested is pretreated as follows before use: the sample to be tested is washed with deionized water, left to dry overnight at room temperature, and then cut into 1-3 mm fragments for standby use. 3. The method for determining the flame retardant of decabromodiphenyl ether in electronic and electrical products according to claim 1, characterized in that in step (1), the amounts of the sample to be tested, deionized water A, deionized water C, 50 mmol/L ferrous sulfate solution, and 30% hydrogen peroxide solution are 1 mg, 20 μL, 400 μL, 100 μL, and 100 μL, respectively. 4. The method for determining the content of decabromodiphenyl ether flame retardant in electronic and electrical products according to claim 1, characterized in that in step (3), the mass of the decabromodiphenyl ether standard substance weighed is 0.50 mg.