The object of the invention is to overcome the defect of the prior art, a kind of method of liquid chromatographic determination of decabromodiphenyl ether content in plastic is provided. The present invention proposes that decabromodiphenyl ether is completely dissolved together with solid plastics, and the large mass transfer resistance between solid and liquid is converted into the small mass transfer resistance inside the liquid phase, thereby greatly reducing the time of analysis and treatment. The invention can realize the rapid analysis of the decabromodiphenyl ether flame retardant content in the plastics of various electronic and electrical products. These electronic and electrical products include televisions, computers, mobile phones, etc. The main components of their plastics are polystyrene, high-impact polystyrene and ABS resin.
The method for determining the content of decabromodiphenyl ether in plastics by liquid chromatography includes the following steps: dissolving the plastics in tetrahydrofuran to form a solution, and after the solution is centrifuged; taking the supernatant for microfiltration, and the filtrate is a solution to be tested by chromatography; The content of decabromodiphenyl ether in the solution to be tested was determined by high performance liquid chromatography.
A method for determining the content of decabromodiphenyl ether in plastics by liquid chromatography, which specifically includes the following steps
(1) collect plastic solids, pulverize; get solid 0.5-1.0g after pulverization, add 50-150mL tetrahydrofuran, stir to make solid dissolve, obtain solution;
(2) get solution 2-10mL, centrifuge more than 3 minutes, draw supernatant after microfiltration, and filtrate is solution to be tested;
(3) Determining the decabromodiphenyl ether content in the solution to be tested by high performance liquid chromatography.
The plastic content in the solution was below 10 mg/mL.
The dissolution time is 10-30 minutes, and it is completely dissolved.
The microfiltration is carried out by using a tetrahydrofuran-resistant filter membrane with a pore size of less than 0.46 μm.
The assay was performed by high performance liquid chromatography with external standard method.
The mobile phase of described high performance liquid chromatography adopts the mixed solvent of tetrahydrofuran and methanol in a volume ratio of 90:10.
The high performance liquid chromatography adopts an ultraviolet detector with a wavelength of 300 nm.
The rotational speed of the centrifugation is greater than 1000 rpm.
(1) Since most of the plastics using decabromodiphenyl ether as flame retardant are polystyrene, and tetrahydrofuran has good solubility for such plastics, and tetrahydrofuran is also a good solvent for decabromodiphenyl ether, its solubility It is 10-20 times that of existing alcohol and ketone solvents (such as isopropanol and acetone) used in various solid-liquid extraction, thus ensuring the rapid dissolution of solid samples. In addition, since all solid substances are completely dissolved in the solvent, the yield problem caused by incomplete extraction of decabromodiphenyl ether in the existing extraction technology is also avoided. Thus, adopting the technology that the tetrahydrofuran proposed by the present invention completely dissolves the solid sample can greatly shorten the sample processing time.
(2) Due to the complex composition of plastic samples, especially for a variety of electronic and electrical plastics, in addition to polystyrene plastics and decabromodiphenyl ether flame retardants, there are inorganic substances such as fillers and dyes. These substances Will interfere with and disrupt chromatographic analysis. For this reason, the present invention adopts the purification technology of first centrifugation and then microfiltration, which has the characteristics of low cost and high applicability.
(3) because the present invention adopts solid sample complete dissolving technology, so in the solution to be tested, in addition to containing the decabromodiphenyl ether that needs to detect, also contain a large amount of polystyrene. Existing HPLC methods for detecting polybrominated diphenyl ethers all use methanol or acetonitrile as the main mobile phase system, and obviously polystyrene has the problem of immiscibility in this mobile phase system, especially for the higher polystyrene content , resulting in a serious decline in the quality of the chromatogram. For this reason, the present invention re-optimizes the mobile phase conditions for chromatographic separation, considers the similarity of the mobile phase and the sample solvent syst
em and the feasibility of reverse-phase rinsing, and obtains a mobile phase system with a mixing ratio of tetrahydrofuran and methanol of 90: 10 through optimization. . Using this mobile phase system can greatly improve the quality of chromatograms and shorten the time of chromatographic analysis.
(4) The present invention adopts the most commonly used HPLC ultraviolet detection and analysis to measure the content of decabromodiphenyl ether. Since tetrahydrofuran is used as the main mobile phase system, and tetrahydrofuran has a high ultraviolet cut-off wavelength, the increase of the detection wavelength can reduce the interference caused by the background absorption of the mobile phase, but the response of decabromodiphenyl ether is also weakened at the same time. The invention comprehensively considers the measurement noise caused by the background absorption of the mobile phase and the signal response of the detection substance, and adopts an ultraviolet detector with a wavelength of 300 nm.