Abstract: Plastic packaging bags for cakes are prone to pungent odors in the production process, and even migrate to cakes, affecting the quality and safety of cakes. This phenomenon is often caused by the use of plastic packaging bags in the complex process of diluting the organic solvents introduced when the adhesive or ink printing, so the need to use gas chromatography in a timely manner for the detection of solvent residues of packaging materials. This article introduced the necessity of detecting the solvent residues in cakes and other plastic composite film packaging bags, and introduced the test process and equipment structure of hydrogen flame gas chromatography in detail. It can provide technical reference for the sanitary chemical properties of packaging materials for customers in various industries. . Key words: cakes, cakes, plastic composite films, plastic bags, odor, gas chromatography, automatic injection, solvent residues, benzene solvents Test significance: Pastries are the most common food in the public life. The types of cakes are also numerous. According to the production process, they are divided into baking, deep-fried, steamed, cooked and moon cakes. The cakes produced by these processes are almost every day. Appeared in the homes of ordinary people, therefore, the quality and safety of cakes is of vital importance to people's physical and mental health. Pastry products often appear moldy, bulky, and non-crispy, etc., and for pastry manufacturers, in addition to often meeting the above-mentioned product problems, they often face large odors in the bags used by the cakes. This odor is similar. The odor of paint or other chemical reagents, in serious cases, the odor will migrate to the cake, resulting in the cake can not be eaten. Most of the odor produced in cakes and pastries is due to residual chemical solvents in the packaging materials. The total amount of solvent residues in the plastic composite film and bags produced by the dry composite method in China must not exceed 5.0 mg/m2 , among which benzenes should not be detected. Therefore, " solvent residue " is one of the monitoring indicators of the monitoring of sanitary chemical performance of cake packaging. Pastry packaging materials are generally divided into plastic composite film, aluminum composite film, aluminum plastic composite film, paper plastic composite film of which four, of which the use of plastic composite film is high, while the aluminum composite film and aluminum plastic composite film It is generally used when there is a high barrier requirement. Pastry plastic composite film packaging bags use dry composite process, that is, the use of organic solvents to dilute the adhesive after coating a layer of film, after oven drying, and then with another layer of film heat paste composite film synthesis process. It is suitable for a variety of substrate films, with a high degree of freedom of substrate selection, and can produce a variety of excellent properties of the composite film. However, if the dry composite plastic bag is improperly treated with residual organic solvents in the post-production process, such as the drying temperature, time, and wind speed, the parameters are unreasonable, and the residual solvent is excessively likely to occur. The odor in the packaging bag further affects the quality of the cake. . In addition, the ink on the plastic package also needs to be dissolved after being dissolved by organic solvents such as ketones during printing, and the problem of residual solvent may also occur. Therefore, it is necessary to use a reasonable gas chromatographic detection device for solvent residue testing. Detection method: The detection of solvent residues in packaging materials was detected by gas chromatography. The gas components volatilized in the packaging materials heated at a fixed temperature and for a period of time were separated using a column, and then the hydrogen flame detector was used for chromatographic analysis of the components. , Usually benzene, ketones, esters, alcohols in the four major components of the content of the test. At present, most of the test residues in domestic test plastic packaging solvents comply with the national standard of GB/T 10004-2008 “Plastic composite film, bag dry compounding, and extrusion compoundingâ€. This standard is mainly aimed at the production of dry composite or extrusion composite processes. Composite film and bag products, but other materials can also be used for solvent residue detection by gas chromatography. We will use a GC-7800 gas chromatograph (including an autosampler) developed by Labthink and used in conjunction with the above standards to perform solvent residual tests on cake plastic bags (dry composite processes) that produce strong odors. 1 , test equipment Labthink 's GC-7800 gas chromatograph developed by Languang Inc. , includes automatic sample introduction, dual-column dual gas system, automatic sample introduction device equipped with a large 300 mL sample vial and two sample preparation thermostatic chambers, and sample chambers. The sample chambers are independent of each other, and the temperature parameters can be set and heated separately. The device can perform double sample test at the same time; the sample chamber temperature control range is 5 °C ~ 200 °C , and the loop sample volume is 0.5 mL , 1.0 mL , 2.0 mL , 3.0 mL four optional, sampling line and injection valve with backwash cleaning function, can effectively avoid sample cross-contamination; chromatograph with constant temperature, program temperature, mixed control of a variety of test modes, 5- order linear control of temperature; double Detector ( FID+TCD ), in which the detection limit of the FID of the hydrogen flame ion detector is not more than 1×10-11 g/s (benzene), and the sensitivity of the thermal conductivity cell detector TCD is not less than 3000 mV·mL/mg (benzene) . The instrument is suitable for the analysis and test of residual solvents of various foods, pharmaceutical packaging plastic films, paper-plastic composite films, cigarette packets and other materials. It can also be applied to the purity analysis of various packaging and printing solvents and solvent moisture content analysis. Institutions, research institutes, packaging companies, food and pharmaceutical industries have the best choice for gas chromatography analysis and control. 2. Test conditions Venue: Jinan Languang Packing Safety Testing Center Column Temperature: 50 °C ~ 150 °C Program temperature increase (The boiling point of the solvent to be measured and the instrument's separation effect setting) 3. Test procedure 3.1 Test principle GC-7800 gas chromatograph is a multi-component mixture separation and analysis tool. It uses inert gas as mobile phase and column separation technology. When multiple analytes enter the column, due to the different partition coefficients of each component in the column, the flow rate of each component in the column is different. After a certain column length, the mixed components leave the column separately. After entering the detector, after being detected, it is converted into an electrical signal and sent to the data processing workstation, thus completing the detection and analysis of the tested substances. 3.2 Preparation of Samples 0.2 m2 cake taken plastic bags test sample, and the sample quickly cut into pieces of 10mm × 30mm, into preheated at 80 ℃ for cleaning the vial quickly sealed with a stopper; and The sealed headspace bottle is placed in a sample preparation thermostatic chamber ( 80 ± 2 °C ) for 30 min . 3.3 test procedure The GC-7800 heats up for automatic sampling and software control programs, and the software automatically reads and calculates the content of each solvent component, so the device is easy to operate: The total amount of solvent residues in the plastic bag samples of the cake was 7.67 mg/m2 , among which the benzene solvent was 0.12 mg/m2 ( the detection limit exceeded 0.01 mg/m2 , which was deemed to have been detected) , and the results between the parallel samples were tested. Relative deviations are less than 10% . Therefore, the total amount of solvent residues in the odor-laden pastry plastic packaging bags exceeds the 5.0 mg/m2 required by the national standard , and the benzene-based solvents are exceeding the standard, which is an important cause of odor. to sum up: Using GC-7800 Gas Chromatograph (with autosampler) test cakes plastic packaging film, the bag solvent residue, to obtain a stable, accurate test results, the reaction may be real health chemical properties cookie packing material. Therefore, when there is a pungent odor in the pastry packaging material used, a high-precision gas chromatograph should be used to detect the residual solvent. Pastry plastic composite film is only a typical representative of all kinds of packaging materials, and other solvent residue test such as aluminum-plastic composite film for meat products, aluminum-coated composite film for milk powder, and tobacco film can all follow this test method. Labthink has been committed to providing professional testing services and equipment for customers around the world. Over the years, it has provided thousands of solvent residue testing services to customers worldwide, providing customers with reliable technical solutions. Central Control And Motor Mold Automotive Air Conditioner Mould In,Injection Mold Mould For Air Conditioner,Automotive Air Conditioner Mould,Automotive Motor Mould Vs Mold Kunshan Wangdaxin Precision Mould Co., Ltd. , https://www.wdxmould.com
Sample chamber temperature: 180 °C (set according to specific conditions)
Detector temperature: 180 °C (visual column temperature setting)
Test gas: pure dry nitrogen Test method: gas chromatography (hydrogen flame detector) 
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How to solve and control the odor of plastic bags used in cakes