The method of determining benzene in plastic coatings is studied

0 Foreword
plastic materials are now widely used in mobile phones, computers and other household electronic products. However, it has its own environmental aging performance, such as ultraviolet light resistance is not ideal, the surface often produces various defects in the process of processing and other shortcomings. For beautification and protection purposes, the surfaces of these plastic materials are often coated with a layer of plastic coatings, which are usually solvent-based
in
. Because of the use of benzene, toluene, xylene, ethyl benzene as a solvent, plastic coatings can have good film-forming properties, and the cost is cheaper, so benzene solvents are used more in plastic coatings. However, these solvents are highly toxic and have a strong toxic effect on the human body, limiting their use in coatings is imperative, so it is of great practical significance to develop the detection method of benzene products in plastic coatings. In this paper, using the gas chromatography method, with orthoenxane as the internal object, a method for determining the content of benzene, toluene, xylene and ethylbenzene in plastic coatings is established, which has the advantages of simple operation and high sensitivity, and is satisfied with the measurement results of the actual plastic coating samples.
1 Test Part
1.1 Instruments and Reagents
Agilent 6890 gas chromatography, with flame ion detector (FID), benzene, toluene, ethyl benzene, phthalates, inter-toluene, xylene, xylene are color spectrum pure, ethyl acetate for analysis pure.
1.2 chromatography condition
Agilent DB-1301 capillary column (6% cyanopropyl benzene-methyl polysilioxane, 60 m×0.32 mm ×1.0 m), in-sample temperature 240 degrees C, detector temperature 260 degrees C; program heating: initial temperature 40 degrees C, maintained at 5 min, 20 degrees C/min rise to 180 degrees C to maintain 5 min;
1.3 Test Method
1.3.1 Relative Mass Correction Factor Determination
Toluene, xylene each 0.02 g (accurate to 0.000 1 g), put in the same dry capacity bottle, add ethyl acetate 2 mL, after coating the sample will be fully shaken. After the instrument is stabilized, the correction factor is calculated according to chromatography conditions and calculated by formula (1).
2 results and discussion
2.1 relative mass correction factor determination
according to the chromatography conditions of this paper, can be positive octane (internal markers), benzene, toluene, mixtures can be effectively separated. The retention time of each adesthet is 13.1 min, orthoethylene 13.3 min, toluene 15.6 min, ethyl benzene 17.9min, xylene 18.1 min, phthalates 18.8 min. Between xylene and xylene can not be effectively separated on the medium polar column, the sum of the two is calculated. The relative mass correction factors of the adlyses were 0.980, 0.991, 1.065, 1.023, and 1.041.
2.2 Actual sample test (see Figure 1)
The actual sample of the plastic coating is determined according to chromatography conditions, as shown in Figure 1, the sample parts are well separated and there is no interference to the parts being analyzed. The test results for each sample are available in Table 1.
tests were carried out on the labeling of samples, and the recovery rate of each adlys was seen in Table 3. As can be known from Table 3, the mark-up recovery rate of benzene is 98.6% to 99.0%, and the results show that the method has a good recovery rate and accuracy. The detection and analysis of benzene products in actual samples can be satisfied.
3 Conclusion
This paper mainly studies the gas chromatography separation analysis method of benzene, toluene, ethylbenzene and xylene in plastic coatings, and the results show that the accuracy and accuracy of this method can meet the separation analysis of the actual plastic coating samples.