Chromatographic analysis device for content of volatile organic compounds in food-grade carbon dioxide

Abstract

The utility model discloses a chromatographic analysis device for the content of volatile organic compounds in food-grade carbon dioxide, which comprises a six-way sampling valve provided with a sample gas inlet, a sample gas outlet, a quantitative container outlet, a quantitative container inlet, a carrier gas inlet and a quantitative gas outlet; two ends of the quantitative container are respectively communicated with the quantitative container outlet and the quantitative container inlet; the inlet of the sample inlet is communicated with the quantitative gas outlet; an inlet of the first chromatographic column is communicated with an outlet of the sample inlet; an inlet of the one-inlet and double-outlet flow control assembly is communicated with an outlet of the first chromatographic column; the inlet of the second chromatographic column is communicated with the first outlet of the flow control assembly; an inlet of the first FID detector is communicated with an outlet of the second chromatographic column; the inlet of the third chromatographic column is communicated with the second outlet of the flow control assembly; the inlet of the second FID detector is communicated with the outlet of the third chromatographic column. According to the utility model, the requirement on the number of detection equipment is reduced, the separation detection of the gas to be detected is completed through one-time sample introduction, and the detection efficiency is greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of gas chromatography analysis equipment, in particular to a chromatographic analysis device for analyzing the content of organic volatiles in food-grade carbon dioxide. Background Art

[0002] Carbon dioxide is a colorless, tasteless, and odorless gas at room temperature. Due to its unique physical properties, it is widely used as a food additive in daily life, primarily in carbonated beverages, tobacco puffing, and food preservation. The quality of carbon dioxide as a food additive is crucial to the health of consumers. Excessive levels of organic compounds such as ethylene oxide, acetaldehyde, vinyl chloride, methanol, and benzene series in carbon dioxide can pose a significant threat to human health.

[0003] In recent years, with the increasing concern of consumers for food safety, my country officially promulgated the national standard "National Food Safety Standard Food Additive Carbon Dioxide" GB1886.228-2016 on August 31, 2016 regarding the food additive carbon dioxide. It stipulates physical and chemical indicators for related organic compounds in the food additive carbon dioxide, and also stipulates chromatographic analysis methods for detecting organic volatiles such as ethylene oxide, acetaldehyde, vinyl chloride, methanol, and benzene series.

[0004] In actual analytical work, the detection of organic compounds in carbon dioxide gas requires three detectors and three chromatographic columns. The chromatographic columns need to be replaced back and forth during the entire detection process, which greatly increases the detection time and reduces the detection efficiency.

[0005] Application number: CN202111675665.9, titled: Patent application for natural gas product quality index analysis equipment, analysis method and application, discloses the use of multiple chromatographic column analysis systems, and sets corresponding injection valves, quantitative tubes, carrier gases, pre-separation columns, chromatographic analysis columns and detectors in each chromatographic column analysis system, so as to detect various gas components in natural gas. Although the technical solution disclosed in the above patent does not require the replacement of chromatographic columns to achieve the detection of multiple gases during the detection process, a corresponding complete set of analysis systems (injection valves, quantitative tubes, carrier gases, pre-separation columns, detectors, etc.) are designed for each chromatographic column. As a result, there are many devices involved in the entire detection process, the detection cost is high, and the amount of operations during the detection process is also large. Utility Model Content

[0006] In view of the above-mentioned defects of the prior art, the purpose of the present invention is to provide a chromatographic analysis device for the content of organic volatiles in food-grade carbon dioxide, which reduces the requirement for the number of detection equipment, completes the separation and detection of the gas to be tested through a single injection, and greatly improves the detection efficiency.

[0007] The utility model achieves its purpose through the following technical solutions:

[0008] Chromatographic analysis device for the content of organic volatiles in food-grade carbon dioxide, including:

[0009] Six-way injection valve, equipped with sample gas inlet, sample gas outlet, quantitative container outlet, quantitative container inlet, carrier gas inlet, and quantitative gas outlet;

[0010] The two ends of the quantitative container are respectively connected to the quantitative container outlet and the quantitative container inlet;

[0011] The sampling port is connected with the quantitative gas outlet;

[0012] a first chromatographic column, the inlet of which is connected to the outlet of the injection port;

[0013] a one-inlet, two-outlet flow control component, the inlet of which is connected to the outlet of the first chromatographic column;

[0014] a second chromatographic column, the inlet of which is connected to the first outlet of the flow control component;

[0015] a first FID detector, an inlet of which is connected to an outlet of the second chromatographic column;

[0016] a third chromatographic column, the inlet of which is connected to the second outlet of the flow control component;

[0017] The inlet of the second FID detector is connected to the outlet of the third chromatographic column.

[0018] Furthermore, the first chromatographic column and the second chromatographic column are capillary chromatographic columns; and the third chromatographic column is a damping column.

[0019] Furthermore, the first chromatographic column quickly separates and discharges vinyl chloride and benzene series; the second chromatographic column separates ethylene oxide and acetaldehyde; and the third separation column controls the separation and discharge of ethylene oxide and acetaldehyde later than vinyl chloride and benzene series in the first chromatographic column.

[0020] Furthermore, it is characterized in that the flow control component is a diverter plate, and the diverter plate is provided with three ports, namely, a P end, an R end and an S end;

[0021] The P end is communicated with the outlet of the first chromatographic column, the R end is communicated with the inlet of the third chromatographic column, and the S end is communicated with the inlet of the second chromatographic column.

[0022] Furthermore, the P end of the diverter plate is alternately connected to the R end and the S end; when vinyl chloride and benzene series enter the diverter plate, the P end is connected to the R end; when ethylene oxide and acetaldehyde enter the diverter plate, the P end is connected to the S end.

[0023] Furthermore, it is characterized in that three connecting channels are provided inside the six-way injection valve; when the six-way injection valve is in the default state, the sample gas inlet is connected to the quantitative container inlet, the sample gas outlet is connected to the quantitative container outlet, and the carrier gas inlet is connected to the quantitative gas outlet; when the six-way injection valve is working, the quantitative container outlet is connected to the quantitative gas outlet, the carrier gas inlet is connected to the quantitative container inlet, and the sample gas inlet is connected to the sample gas outlet.

[0024] Furthermore, the quantitative container is a quantitative ring, and the capacity of the quantitative ring is 1 ml.

[0025] Furthermore, the carrier gas is nitrogen.

[0026] Furthermore, the operating temperature of the first FID detector and the second FID detector is 290-310°C, the flow rate of the auxiliary gas is 380-420 mL / min, and the flow rate of the fuel gas is 38-42 mL / min;

[0027] The tail gas flow rate of the second and third chromatographic columns was 22-28 mL / min; the column flow rate of the first chromatographic column was 2.3-2.7 mL / min;

[0028] The injection port temperature is 220-260°C; the temperatures of the second chromatographic column and the third chromatographic column are 140-160°C.

[0029] Furthermore, the ratio of the gas flow rates flowing through the second chromatographic column to the gas flow rate flowing through the third chromatographic column is 4.5-5.2:1.

[0030] Due to the adoption of the above technical solution, the utility model has the following advantages:

[0031] 1. The utility model uses a flow control component and a damping column to realize the heart cutting method to analyze organic compounds such as ethylene oxide, acetaldehyde, vinyl chloride, methanol and benzene series in food carbon dioxide. In this way, all 10 components can be separated with only one injection, realizing one-time detection.

[0032] 2. The utility model reduces the three detectors required for the national standard chromatographic analysis conditions to two detectors, and reduces the three chromatographic columns (with separation function) to two chromatographic columns, saving detection costs, while also reducing the time consumed in replacing chromatographic columns back and forth, thereby improving work efficiency.

[0033] 3. Through the coordination of the damping column and the chromatographic column, the substances to be tested in the sample gas can be divided into two categories, and all the detection can be achieved by using two detectors.

[0034] Other advantages, objectives, and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art to some extent, or they may be taught from the practice of the present invention based on the following examination and study. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings of the present invention are as follows:

[0036] Figure 1 Schematic diagram of the chromatographic analysis device for the content of volatile organic compounds in food-grade carbon dioxide in this embodiment.

[0037] In the figure: 1. Six-way injection valve; A. Sample gas inlet; B. Sample gas outlet; C. Quantitative container outlet; D. Quantitative gas outlet; E. Carrier gas inlet; F. Quantitative container inlet; 2. Quantitative container; 3. Injection port; 4. First chromatographic column; 5. Second chromatographic column; 6. Third chromatographic column; 7. Flow control assembly; 8. First FID detector; 9. Second FID detector; 10. Carrier gas. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] Example:

[0040] like Figure 1 As shown, the chromatographic analysis device for the content of organic volatiles in food-grade carbon dioxide includes:

[0041] The six-way injection valve 1 is provided with a sample gas inlet A, a sample gas outlet B, a quantitative container outlet C, a quantitative container inlet F, a carrier gas inlet E, and a quantitative gas outlet D;

[0042] The two ends of the quantitative container 2 are connected to the quantitative container outlet C and the quantitative container inlet F respectively;

[0043] The inlet 3 is connected to the quantitative gas outlet D;

[0044] The first chromatographic column 4, the inlet of which is connected to the outlet of the injection port 3, controls the separation of vinyl chloride and benzene series;

[0045] A one-inlet and two-outlet flow control component 7, the inlet of which is connected to the outlet of the first chromatographic column 4;

[0046] The inlet of the second chromatographic column 5 is connected to the first outlet of the flow control component 7 to control the separation of ethylene oxide and acetaldehyde;

[0047] a first FID detector 8 , the inlet of which is connected to the outlet of the second chromatographic column 5 ;

[0048] The inlet of the third chromatographic column 6 is connected to the second outlet of the flow control component 7;

[0049] The inlet of the second FID detector 9 is connected to the outlet of the third chromatographic column 6 .

[0050] In this embodiment, the first and second chromatographic columns 4 and 5 are capillary columns, and the third chromatographic column 6 is a damping column. Specifically, the first chromatographic column 4 is a DB-HeavyWAX (30m×320μm×0.5μm) capillary column, the second chromatographic column 5 is an HP-Plot Q PT (30m×530μm×40μm) capillary column, and the third chromatographic column 6 is a 2.86m×250μm×0μm damping column. The first chromatographic column 4 rapidly separates and discharges vinyl chloride and benzene series; the second chromatographic column 5 separates ethylene oxide and acetaldehyde; and the third separation column ensures that ethylene oxide and acetaldehyde are separated and discharged later than vinyl chloride and benzene series in the first chromatographic column 4.

[0051] In this embodiment, the flow control component 7 is a diverter plate, which is provided with three ports, namely, the P end, the R end and the S end;

[0052] The P end is connected to the outlet of the first chromatographic column 4, the R end is connected to the inlet of the third chromatographic column 6, and the S end is connected to the inlet of the second chromatographic column 5;

[0053] The P end of the diverter plate is alternately connected to the R end and the S end; when vinyl chloride and benzene series enter the diverter plate, the P end is connected to the R end; when ethylene oxide and acetaldehyde enter the diverter plate, the P end is connected to the S end.

[0054] In this embodiment, three connecting channels are provided inside the six-way injection valve 1; when the six-way injection valve 1 is in the default state, the sample gas inlet A is connected to the quantitative container inlet F, the sample gas outlet B is connected to the quantitative container outlet C, and the carrier gas inlet E is connected to the quantitative gas outlet D; when the six-way injection valve 1 is working, the quantitative container outlet C is connected to the quantitative gas outlet D, the carrier gas inlet E is connected to the quantitative container inlet F, and the sample gas inlet A is connected to the sample gas outlet B.

[0055] In this embodiment, it is characterized in that the quantitative container 2 is a quantitative ring with a capacity of 1 ml; and the carrier gas 10 is nitrogen.

[0056] In this embodiment, it is characterized in that the operating temperature of the first FID detector 8 and the second FID detector 9 is 300°C, the flow rate of the supporting combustion gas is 400 mL / min, and the fuel gas flow rate is 40 mL / min; the tail gas flow rate of the second chromatographic column 5 and the third chromatographic column 6 is 25 mL / min; the column flow rate of the first chromatographic column 4 is 2.5 mL / min; the temperature of the injection port 3 is 250°C; the temperature of the second chromatographic column 5 and the third chromatographic column 6 is 150°C; and the ratio of the gas flow rate flowing through the second chromatographic column 5 and the third chromatographic column 6 is 5:1.

[0057] In this embodiment, the chromatographic analysis method for the content of organic volatiles in food-grade carbon dioxide includes the following steps:

[0058] Set the six-way injection valve 1 and the flow control component 7 (P end and R end are connected) to the initial state, and follow Figure 1 Connect all devices of this device as shown.

[0059] The sample gas enters the six-way injection valve 1 through the sample gas inlet A and flows along the sample gas inlet A, the quantitative container inlet F, the quantitative container 2, the quantitative container outlet C, and the sample gas outlet B; at the same time, the carrier gas 10 enters the carrier gas inlet E and flows along the carrier gas inlet E, the quantitative gas outlet D, the injection port 3, the flow control component 7, and the third chromatographic column 6 into the first FID detector 8, replacing the gas in the flow path with nitrogen.

[0060] The temperature of all devices was set according to the parameters set in the embodiment. The initial temperature of the first chromatographic column 4, the second chromatographic column 5, and the third chromatographic column 6 was set to 40°C and maintained for 5 minutes, and then increased to 150°C at a rate of 15°C / min and maintained.

[0061] During testing, the six-way injection valve 1 rotates 60 degrees counterclockwise. At this point, the dosing container outlet C connects to the dosing gas outlet D, the carrier gas inlet E connects to the dosing container inlet F, and the sample gas inlet A connects to the sample gas outlet B. Nitrogen then flows along the carrier gas inlet E, dosing container inlet F, dosing container 2, dosing container outlet C, and dosing gas outlet D into the injection port 3. Under its higher pressure, the carrier gas 10 carries the sample gas along with it.

[0062] After entering the inlet 3 and being heated, the sample gas and carrier gas 10 enter the first chromatographic column 4. Due to the interference of the resistance of the third chromatographic column 6, components with fast separation speeds, such as vinyl chloride and benzene series, flow out first in the first chromatographic column 4, while ethylene oxide and acetaldehyde flow out later in the first chromatographic column 4. The gas then enters the splitter plate, flows out from the P end to the R end, enters the third chromatographic column 6, and then enters the first FID detector 8 for detection, where peaks of vinyl chloride, methanol, benzene, toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene are detected.

[0063] After vinyl chloride, benzene series, and other substances enter the third chromatographic column 6, the manifold is controlled to connect its P and S ends. During this process, the gas ratio flowing into the third chromatographic column 6 and the second chromatographic column 5 is controlled to be 5:1. The components containing ethylene oxide and acetaldehyde that exit later enter the second chromatographic column 5, where they are separated and finally enter the second FID detector 9 for detection, producing peaks for ethylene oxide and acetaldehyde, ultimately resulting in a gas chromatogram.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A chromatographic analysis device for the content of organic volatiles in food-grade carbon dioxide, characterized in that: include: Six-way injection valve, equipped with sample gas inlet, sample gas outlet, quantitative container outlet, quantitative container inlet, carrier gas inlet, and quantitative gas outlet; The two ends of the quantitative container are respectively connected to the quantitative container outlet and the quantitative container inlet; The sampling port, the inlet is connected with the quantitative gas outlet; a first chromatographic column, the inlet of which is connected to the outlet of the injection port; a one-inlet, two-outlet flow control component, the inlet of which is connected to the outlet of the first chromatographic column; a second chromatographic column, the inlet of which is connected to the first outlet of the flow control component; a first FID detector, an inlet of which is connected to an outlet of the second chromatographic column; a third chromatographic column, the inlet of which is connected to the second outlet of the flow control component; The inlet of the second FID detector is connected to the outlet of the third chromatographic column.

2. The chromatographic analysis device for the content of volatile organic compounds in food-grade carbon dioxide according to claim 1, characterized in that: The first chromatographic column and the second chromatographic column are capillary chromatographic columns; the third chromatographic column is a damping column.

3. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to claim 1, characterized in that: The first chromatographic column quickly separates and discharges vinyl chloride and benzene series; the second chromatographic column separates ethylene oxide and acetaldehyde; the third separation column controls the separation and discharge of ethylene oxide and acetaldehyde later than vinyl chloride and benzene series in the first chromatographic column.

4. The chromatographic analysis device for the content of volatile organic compounds in food-grade carbon dioxide according to any one of claims 1 to 3, characterized in that: The flow control component is a diverter plate, which is provided with three ports, namely, the P end, the R end and the S end; The P end is communicated with the outlet of the first chromatographic column, the R end is communicated with the inlet of the third chromatographic column, and the S end is communicated with the inlet of the second chromatographic column.

5. The chromatographic analysis device for the content of volatile organic compounds in food-grade carbon dioxide according to claim 4, characterized in that: The P end of the diverter plate is alternately connected to the R end and the S end; when vinyl chloride and benzene series enter the diverter plate, the P end is connected to the R end; when ethylene oxide and acetaldehyde enter the diverter plate, the P end is connected to the S end.

6. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to any one of claims 1 to 3, characterized in that: Three connecting channels are provided inside the six-way injection valve; when the six-way injection valve is in the default state, the sample gas inlet is connected to the quantitative container inlet, the sample gas outlet is connected to the quantitative container outlet, and the carrier gas inlet is connected to the quantitative gas outlet; when the six-way injection valve is working, the quantitative container outlet is connected to the quantitative gas outlet, the carrier gas inlet is connected to the quantitative container inlet, and the sample gas inlet is connected to the sample gas outlet.

7. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to claim 1, characterized in that: The quantitative container is a quantitative ring, and the capacity of the quantitative ring is 1 mL.

8. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to claim 1, characterized in that: The carrier gas is nitrogen.

9. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to any one of claims 1, 2, 3, 7, and 8, characterized in that: The operating temperature of the first FID detector and the second FID detector is 290-310°C, the flow rate of the auxiliary gas is 380-420 mL / min, and the flow rate of the fuel gas is 38-42 mL / min; The tail gas flow rate of the second and third chromatographic columns was 22-28 mL / min; the column flow rate of the first chromatographic column was 2.3-2.7 mL / min; The injection port temperature is 220-260°C; the temperatures of the second chromatographic column and the third chromatographic column are 140-160°C.

10. The chromatographic analysis device for organic volatile matter content in food-grade carbon dioxide according to claim 1, characterized in that: The ratio of the gas flow rates flowing through the second chromatographic column to the third chromatographic column is 4.5-5.2:1.

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