Waste Edible Oil or Its Recycled Product Detection Device and Its Detection Method

Abstract

A detection device for waste edible oils or their recycled products and a detection method thereof, wherein the detection device is a high-performance liquid chromatography detection system consisting of a quantitative loop, an injector, a pump, a chromatographic column, a detector, and a recorder, and the chromatographic column is composed of three stainless steel columns filled with styrene-divinylbenzene copolymer porous gel particles with a particle size of 5 μm and pore sizes of #imgabs0# and #imgabs1#, respectively. Utilizing the technology provided by the present invention, not only can the qualitative and quantitative detection of fatty acids and fatty acid methyl esters in waste edible oils or their recycled products be combined and completed, but the detection of other components in waste edible oils or their recycled products can also be further expanded, thereby improving detection efficiency and detection accuracy, providing more high-quality detection items and detection data for waste edible oils or their recycled products, and reducing maintenance costs and detection fees, providing better services for the recycling of waste edible oils.

Description

Technical Field

[0001] The present invention relates to a detection device and a detection method thereof, and in particular to a detection device and a detection method thereof for waste edible oil or its recycled product, belonging to the technical field of oil product detection devices and detection methods thereof. Background Art

[0002] Edible oils and fats include two major categories: animal fats and vegetable oils. Among them: animal fats include lard, body fat and milk fat of cattle, sheep and other animals, as well as fat of marine fish; vegetable oils include soybean oil, rapeseed oil, peanut oil, cottonseed oil, sesame oil, sunflower oil, linseed oil, walnut oil, corn oil, rice bran oil, etc., as well as woody plant oils such as palm oil, olive oil, tea oil, etc.

[0003] Waste cooking oil (UCO) usually refers to the grease, oil-water mixture and grease obtained after separation treatment in oil-water separators, grease traps, etc. in food waste. It mainly includes the grease (commonly known as slop oil, swill oil) or oil-water mixture produced after solid-liquid separation and oil-water separation of food waste, the grease (commonly known as gutter oil, swill oil) or oil-water mixture discharged from the kitchens of catering units or residents' kitchens into sewage pipes or municipal pipelines and obtained through oil-water separation devices or manual cleaning (commonly known as gutter oil) or oil-water mixture, and the waste oil from frying food in food processing units or expired waste oil (commonly known as old cooking oil).

[0004] The recycling of waste cooking oil can not only reduce its pollution to the environment and alleviate the pressure of its transportation and disposal, but also the recycled products after processing and refining of waste cooking oil can become raw materials for a variety of chemical products, such as paint, soap, plasticizer, bio-emulsifier, biodiesel, etc. It can not only turn waste into treasure, benefit the country and the people, but also reduce people's dependence on oil. Therefore, it is of great significance in environmental protection, energy conservation and carbon reduction, and can contribute to the sustainable development of mankind.

[0005] The composition of waste cooking oils and fats is quite complex, mainly including polymerized triglycerides, triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters. Among them, the content of fatty acids and fatty acid methyl esters in waste cooking oils and fats not only affects the quality and performance of the waste cooking oil recycled products themselves, but also has a certain impact on the further production process of biofuels. Therefore, in the trading market of waste cooking oils and fats or their recycled products, it is usually necessary to provide a test report on the relevant components and content of waste cooking oils and fats or their recycled products.

[0006] Due to the shortcomings of existing technologies, waste edible oils and fats or their recycled products can currently only provide test reports on the content of fatty acids and fatty acid methyl esters.

[0007] The existing method for detecting the fatty acid content of waste edible oils and fats or their recycled products is to first determine the acid value by acid-base titration, and then estimate the fatty acid content based on the molecular weight of different fatty acids. The specific process is as follows:

[0008] First, determine the amount of alkali standard solution consumed to neutralize the acid contained in the waste edible oil or its recycled products to obtain the molar number of alkali consumed, and then convert it into the molar number of acid contained in the waste edible oil. Because the acid in the waste edible oil is a mixture of multiple fatty acids, the result can only be used to estimate the fatty acid content based on a specific fatty acid molecular weight, such as estimating based on a lauric acid molecular weight of 200, or estimating based on a palmitic acid molecular weight of 256, or estimating based on an oleic acid molecular weight of 282, etc.

[0009] The existing technology for detecting the content of fatty acid methyl esters in waste edible oils or their recycled products is to use gas chromatography to complete the relevant work.

[0010] However, since the main components of waste edible oils or their recycled products are high-boiling-point substances, the test samples will cause serious contamination to the gas chromatograph's inlet and chromatographic column during the detection process, which will not only easily clog the inlet but also render the chromatographic column unusable, thereby causing a sharp increase in the maintenance cost of the gas chromatograph and the cost of its consumables. The detection costs remain high and the detection efficiency cannot be improved. Summary of the Invention

[0011] To address the deficiencies of the prior art, the present invention provides a device and method for detecting waste edible oils and fats or their recycled products, the purpose of which is to:

[0012] Through a detection device and a detection method for waste edible oils or their recycled products, the detection of fatty acid and fatty acid methyl ester content of waste edible oils or their recycled products, which requires multiple devices and methods to complete in the prior art, is combined together to improve the detection efficiency and detection accuracy, and further expand its detection scope, providing more high-quality detection items and detection data for waste edible oils or their recycled products. On the basis of improving the detection capability and detection accuracy of waste edible oils or their recycled products, the maintenance cost of the detection equipment is reduced, the detection efficiency is improved, the detection cost is reduced, and better services are provided for the recycling and utilization of waste edible oils.

[0013] To achieve the above-mentioned object, the present invention first provides a detection device for waste edible oil or its recycled product, and its technical solution is as follows:

[0014] A device for detecting waste edible oils and fats or their recycled products is a high performance liquid chromatography detection system comprising a quantitative loop, an injector, a pump, a chromatographic column, a detector, and a recorder, wherein:

[0015] The chromatographic column is composed of three 300mm×7.5mm stainless steel columns connected in series. The filler of the stainless steel column is porous gel particles made of styrene-divinylbenzene copolymer. The particle size of the gel particles is 5μm and the pore size is and Among them, the pore size is filled The stainless steel column of gel particles constitutes a first filling column, which is connected to the pump and filled with The stainless steel column of gel particles constitutes a third filling column, which is connected to the detector and filled with The stainless steel column of gel particles constitutes a second filling column, and both ends of the second filling column are connected to the first filling column and the third filling column respectively.

[0016] Optionally, the detector is a differential refractive index detector.

[0017] Furthermore, the present invention also provides a detection method for detecting waste edible oils and fats or their recycled products using the above-mentioned detection device for waste edible oils and fats or their recycled products, comprising the following steps:

[0018] The construction of the detection device, determination of the detection conditions, preparation of the standard sample solution, determination of the standard time and standard area, preparation of the test sample, and determination of the detected substances and their contents in the test sample, including:

[0019] The assembly of the detection device includes combining the quantitative loop, the sample injector, the pump, the chromatographic column, the detector, and the recorder according to the requirements of the above detection device to form a high performance liquid chromatography detection system for detecting waste edible oils and fats or their recycled products;

[0020] Determination of the detection conditions includes determination of the flow rate of the pump, the column temperature of the chromatographic column, the operating temperature of the detector, the capacity of the quantitative loop and the type of the mobile phase;

[0021] The preparation of the standard sample solution comprises taking a certain amount of a test standard substance that may contain components in waste edible oils and fats or their regenerated products, dissolving and diluting it with an organic solvent, dehydrating and drying it with a desiccant, and filtering it to obtain the standard solution;

[0022] Determining the standard time and standard area includes taking the standard sample solution, passing it through the quantitative loop and the injector, and then injecting it into the waste edible oil or its recycled product detection device with determined detection conditions; after the detector detects and the recorder records the chromatographic peak of the standard sample solution, defining the retention time of the chromatographic peak of the standard sample solution as the standard time of the same component substance as the inspection standard contained in the waste edible oil or its recycled product; defining the chromatographic peak area corresponding to the content of the standard sample solution that meets the recovery rate standard and the relative standard deviation requirements as the standard area of the amount of substance contained in the standard sample;

[0023] The preparation of the sample to be tested includes taking a certain amount of waste edible oil or its recycled product, dissolving and diluting it with the same organic solvent as the test standard, dehydrating and drying it with the same desiccant as the standard sample, and filtering it to obtain the sample liquid to be tested;

[0024] The determination of the detected substance and its content in the test sample includes taking the test sample liquid and performing the same high performance liquid chromatography test on the test sample liquid according to the same process and method as the steps for determining the standard time and standard area, and after the detector detects and the recorder records all chromatographic peaks of the test sample liquid, comparing the retention time and chromatographic peak area of each chromatographic peak of the test sample liquid with the standard time and the standard area, wherein:

[0025] If the retention time of a chromatographic peak in the sample solution falls within the acceptable error range of a certain standard time, it is determined that the detected substance represented by the chromatographic peak and the test standard corresponding to the standard time are the same substance;

[0026] By comparing the chromatographic peak area of the test sample liquid determined to be the same substance with the standard area of the standard sample corresponding to the same substance, the amount of the detected substance in the test sample liquid relative to the standard sample can be obtained. Then, based on the amount of the detected substance relative to the standard sample combined with its sampling volume, the content of the detected substance in the waste edible oil or its recycled product can be calculated.

[0027] Furthermore, the detection method:

[0028] The flow rate of the pump is 0.8±0.05 mL / min, the column temperature of the chromatographic column is 35±0.5° C., the operating temperature of the detector is 35±0.5° C., the capacity of the quantitative loop is set to 10±0.5 μL, and the mobile phase is tetrahydrofuran.

[0029] Optional:

[0030] The test standard is at least one of triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters.

[0031] Optionally, in the step of preparing the standard sample solution, the sampling amount of the test standard is 0.5±0.05 g.

[0032] Furthermore, the organic solvent is tetrahydrofuran.

[0033] Furthermore, the desiccant is anhydrous sodium sulfate.

[0034] Furthermore, the acceptable deviation range of the standard time is ±5% min of the standard time.

[0035] Furthermore, the standard area should meet a recovery rate standard of 95-105%, and a relative standard deviation requirement of RSD≤2.0%.

[0036] Compared with the prior art, the present invention has the following beneficial effects and significant improvements:

[0037] 1) The waste edible oil or its recycled product detection device provided by the present invention is a high performance liquid chromatography detection system consisting of a quantitative loop, an injector, a pump, a chromatographic column, a detector and a recorder, wherein the chromatographic column is three 300mm×7.5mm columns filled with particles of 5μm and the pore sizes are respectively and A high-efficiency size exclusion chromatography column, constructed by connecting stainless steel columns with porous gel particles of styrene-divinylbenzene copolymer in series, can be used in a high-performance liquid chromatography detection system to not only combine the qualitative and quantitative detection of fatty acids and fatty acid methyl esters in waste edible oils or their recycled products, but also further expand the detection of other components in waste edible oils or their recycled products. This not only improves detection efficiency and accuracy, providing more high-quality detection items and data for waste edible oils or their recycled products, but also reduces the maintenance cost of the detection equipment and testing fees, providing better services for the recycling and utilization of waste edible oils;

[0038] 2) The device and method for detecting waste edible oils or their recycled products provided by the present invention not only provide a new device and method for detecting waste edible oils or their recycled products, but more importantly, provide a new approach and method for detecting waste edible oils or their recycled products, open up a new application research field for high-efficiency size exclusion chromatography, and provide a standardized detection method for different detection items of oil and fat products. These are highly pioneering and creative, and are a milestone in the field of oil and fat product detection.

[0039] 3) The waste edible oil or its recycled product detection device and detection method provided by the present invention have a unique and ingenious technical solution and are simple and convenient to operate. They can not only obtain detection results quickly and accurately, but also ensure that the detection equipment can work stably for a long time, reduce detection costs, simplify detection operations, reduce maintenance time and maintenance costs, and improve detection efficiency and detection accuracy. Therefore, they are of great value for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention and the technical effects of implementing the present invention, a brief introduction is given below to the drawings used in the embodiments of the present invention.

[0041] Obviously:

[0042] The drawings described below are only drawings of some embodiments of the present invention. Those skilled in the art can derive other drawings based on these drawings without inventive effort. However, these other drawings are also included in the drawings required for use in the embodiments of the present invention.

[0043] in:

[0044] Figure 1 A schematic structural diagram of a device for detecting waste edible oils and fats or their recycled products provided by an embodiment of the present invention;

[0045] Figure 2 The HPLC chromatogram of the triglyceride standard provided in the embodiment of the present invention;

[0046] Figure 3 HPLC chromatograms of diglyceride standard and monoglyceride standard provided in the embodiments of the present invention;

[0047] Figure 4 The HPLC chromatogram of the fatty acid standard provided in the embodiment of the present invention;

[0048] Figure 5 The high performance liquid chromatogram of the fatty acid methyl ester provided in the embodiment of the present invention;

[0049] Figure 6 A high performance liquid chromatogram of the components contained in a 20.0250 g waste edible oil sample provided in an embodiment of the present invention;

[0050] Figure 7 for Figure 6 A partial enlarged view of . DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions, beneficial effects and significant improvements of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the reaction formulas provided in the embodiments of the present invention. Obviously, all the embodiments described are only some embodiments of the present invention, rather than all embodiments.

[0052] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0053] It should be noted that:

[0054] The terms "first", "second", etc. in the specification and claims of the present invention and the drawings of the embodiments of the present invention are only used to distinguish different objects rather than to describe a specific order. In addition, the term "comprise" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units that are inherent to these processes, methods, products or devices.

[0055] What needs to be understood is:

[0056] In the description of the embodiments of the present invention, some basic operation terms commonly used in the art are used, such as "dissolve", "dilute", "filter" and "dry", etc. These terms should be understood in a broad sense. They can refer to conventional operations performed by various conventional equipment and instruments in the art, or they can refer to program-controlled operations, unmanned automatic operations, etc. performed by the latest equipment. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to specific circumstances and adopt specific operation methods to achieve their operation purposes.

[0057] It should also be noted that:

[0058] The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. In addition, the solvents, standards, samples to be tested, equipment, devices, etc. involved in the following specific embodiments are all commercially available.

[0059] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0060] Example 1

[0061] This embodiment provides a device for detecting waste edible oils and fats or their recycled products.

[0062] like Figure 1 The structural diagram of a device for detecting waste edible oil or its recycled product provided by an embodiment of the present invention is shown as follows:

[0063] A device for detecting waste edible oils and fats or their recycled products is a high performance liquid chromatography detection system comprising a quantitative loop, an injector, a pump, a chromatographic column, a detector, and a recorder (not shown in the figure), wherein:

[0064] The chromatographic column is composed of three 300mm×7.5mm stainless steel columns connected in series. The filler of the stainless steel column is porous gel particles made of styrene-divinylbenzene copolymer. The particle size of the gel particles is 5μm and the pore size is and Among them, the pore size is filled The stainless steel column of gel particles constitutes the first filling column, which is connected to the pump and filled with The stainless steel column of gel particles constitutes the third filling column, which is connected to the detector and filled with The stainless steel column of the gel particles constitutes a second filling column, and both ends of the second filling column are respectively connected to the first filling column and the third filling column.

[0065] From the above description, we can see that:

[0066] The waste edible oil or its recycled product detection device provided in this embodiment is a high performance liquid chromatography detection system comprising a quantitative loop, an injector, a pump, a chromatographic column, a detector and a recorder, wherein the chromatographic column is three 300mm×7.5mm columns filled with particles of 5μm and the pore sizes are respectively and The high-efficiency space exclusion chromatography column composed of styrene-divinylbenzene copolymer porous gel particles and stainless steel columns connected in series can be used in a high-performance liquid chromatography detection system to not only combine the qualitative and quantitative detection of fatty acids and fatty acid methyl esters in waste edible oils or their recycled products, but also further expand the detection of other components in waste edible oils or their recycled products. This not only improves the detection efficiency and detection accuracy, provides more high-quality detection items and detection data for waste edible oils or their recycled products, but also reduces the maintenance cost and detection fee of the detection equipment, providing better services for the recycling and utilization of waste edible oils.

[0067] Optionally, in this embodiment, the detector is a differential refractive index detector.

[0068] The differential refractive index detector is a universal detector that can be used with an infusion pump, chromatographic column, injector, etc. to form a gel permeation chromatography or high performance liquid chromatography system. It can also be used as a separate analytical instrument with an appropriate injection system.

[0069] Example 2

[0070] This embodiment provides a detection method for detecting waste edible oils and fats or their recycled products using the detection device for waste edible oils and fats or their recycled products provided in Example 1, comprising the following steps:

[0071] The construction of the detection device, determination of the detection conditions, preparation of the standard sample solution, determination of the standard time and standard area, preparation of the test sample, and determination of the detected substances and their contents in the test sample, including:

[0072] The assembly of the detection device includes combining a quantitative loop, a sample injector, a pump, a chromatographic column, a detector, and a recorder according to the requirements of the detection device provided in Example 1 to form a high performance liquid chromatography detection system for detecting waste edible oils and fats or their recycled products;

[0073] The determination of detection conditions includes the flow rate of the pump, the temperature of the chromatographic column, the working temperature of the detector, the capacity of the quantitative loop and the type of mobile phase;

[0074] The preparation of the standard sample solution includes taking a certain amount of the test standard substance that may contain components in waste edible oils and fats or their recycled products, dissolving and diluting it with an organic solvent, dehydrating and drying it with a desiccant, and filtering it;

[0075] The determination of the standard time and the standard area includes taking the above-mentioned standard sample solution through a quantitative loop and an injector and injecting it into a waste edible oil or its recycled product detection device with determined detection conditions, and after the detector detects and the recorder records the chromatographic peak of the standard sample solution, defining the retention time of the chromatographic peak of the standard sample solution as the standard time of the same component substance contained in the waste edible oil or its recycled product, and defining the chromatographic peak area corresponding to the content of the standard sample solution that meets the recovery rate standard and the relative standard deviation requirements as the standard area of the amount of substance contained in the standard sample;

[0076] Preparation of the test sample includes taking a certain amount of waste edible oil or its regenerated product, dissolving and diluting it with the same organic solvent as that used to dissolve and dilute the test standard, dehydrating and drying it with the same desiccant as that used to dry the standard sample, and filtering it to obtain the test sample solution;

[0077] The determination of the detected substances and their contents in the sample to be tested includes taking the sample liquid to be tested and performing the same high performance liquid chromatography test on the sample liquid to be tested according to the same process and method as the steps for determining the standard time and standard area, and after the detector detects and the recorder records all the chromatographic peaks of the sample liquid to be tested, comparing the retention time of each chromatographic peak of the sample liquid to be tested and the chromatographic peak area thereof with the standard time and standard area, wherein:

[0078] If the retention time of a chromatographic peak in the sample solution falls within the acceptable error range of a certain standard time, then it is determined that the detected substance represented by the chromatographic peak and the test standard corresponding to the standard time are the same substance;

[0079] By comparing the chromatographic peak area of the test sample liquid determined to be the same substance with the standard area of the corresponding standard sample of the same substance, the amount of the detected substance in the test sample liquid relative to the standard sample can be obtained. Then, based on the amount of the detected substance relative to the standard sample combined with its sampling volume, the content of the detected substance in the waste edible oil or its recycled product can be calculated.

[0080] In this embodiment, the detection conditions are set as follows:

[0081] The pump flow rate was 0.8±0.05 mL / min, the column temperature was 35±0.5°C, the detector operating temperature was 35±0.5°C, the quantitative loop capacity was 10±0.5 μL, and tetrahydrofuran was used as the mobile phase;

[0082] The test standard can be selected from at least one of triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters; and

[0083] In the above test process, the sample volume of the test standard is generally set to 0.5±0.05g, tetrahydrofuran is used as the organic solvent, and anhydrous sodium sulfate is used as the desiccant;

[0084] The acceptable deviation range of standard time is set as standard time ±5%min;

[0085] The recovery rate of the standard area should be set to 95-105%, and the relative standard deviation requirement should be set to RSD ≤ 2.0%

[0086] Specifically, the qualitative determination of substances contained in waste edible oils and fats or their recycled products is carried out in the following manner:

[0087] Take 0.5 g of triglyceride standard, diglyceride standard, monoglyceride standard, fatty acid standard and fatty acid methyl ester standard respectively, mix them, add tetrahydrofuran to dilute the mixture to 10 mL, then add 1.0 g of anhydrous sodium sulfate, stir, let it stand until it clarifies, and filter to obtain a mixture standard sample solution of triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters; or

[0088] 0.5 g of triglyceride standard, diglyceride standard, monoglyceride standard, fatty acid standard and fatty acid methyl ester standard were taken respectively, and then tetrahydrofuran was added to dilute them to 10 mL, and then 1.0 g of anhydrous sodium sulfate was added to each of them, stirred, and then allowed to stand for clarification and then filtered to obtain triglyceride standard sample solution, diglyceride standard sample solution, monoglyceride standard sample solution, fatty acid standard sample solution and fatty acid methyl ester standard sample solution respectively;

[0089] The waste edible oil or its recycled product detection device provided in Example 1 was turned on, and the flow rate of the pump of the waste edible oil or its recycled product detection device was set to 0.8±0.05 mL / min, the column temperature of the chromatographic column was set to 35±0.5°C, the detector operating temperature was set to 35±0.5°C, the quantitative loop capacity was set to 10±0.5 μL, and tetrahydrofuran was used as the mobile phase;

[0090] Then, 10 μL of the mixture standard sample solution is injected into the waste edible oil or its recycled product detection device through the quantitative loop and the sample injector, or triglyceride standard sample solution, diglyceride standard sample solution, monoglyceride standard sample solution, fatty acid standard sample solution and fatty acid methyl ester standard sample solution are respectively injected into the waste edible oil or its recycled product detection device every 35 minutes. After the detector in the waste edible oil or its recycled product detection device detects them respectively and the recorder records them, the high performance liquid chromatogram of the mixture standard sample solution or the triglyceride standard sample solution, diglyceride standard sample solution, monoglyceride standard sample solution, fatty acid standard sample solution and fatty acid methyl ester standard sample solution can be obtained, as shown in FIG. Figures 2 to 5 As shown, where:

[0091] Figure 2 The HPLC chromatogram of the triglyceride standard provided in the embodiment of the present invention shows that the retention time of triglyceride is 19.019 min;

[0092] Figure 3 The HPLC chromatograms of the diglyceride standard and the monoglyceride standard provided in the embodiment of the present invention show that the retention time of diglyceride is 19.464 min, and the retention time of monoglyceride is 20.613 min;

[0093] Figure 4 The HPLC chromatogram of the fatty acid standard provided in the embodiment of the present invention shows that the retention time of the fatty acid is 24.450 min;

[0094] Figure 5 The high performance liquid chromatogram of the fatty acid methyl ester provided in the embodiment of the present invention shows that the retention time of the fatty acid methyl ester is 31.935 min;

[0095] According to the above chromatogram, the retention time of the chromatographic peaks representing the triglyceride standard, the diglyceride standard, the monoglyceride standard, the fatty acid standard and the fatty acid methyl ester standard can be defined as the standard time of the same component substance contained in the waste edible oil or its recycled product. If the retention time of a chromatographic peak in the sample liquid under test falls within the acceptable error range of a certain standard time, it can be qualitatively determined that the detected substance represented by the chromatographic peak is the same substance as the test standard corresponding to the standard time;

[0096] Generally, the acceptable deviation range of chromatographic peaks representing the same substance is ±5% min of the standard time.

[0097] The quantitative detection of fatty acids and fatty acid methyl esters contained in waste edible oils and fats or their recycled products adopts the following method:

[0098] First, a sample of waste edible oil or fat or its regeneration product in which no fatty acid methyl esters (FAME) were detected by gas chromatography was selected, and a small amount of a FAME standard was added and mixed. The actual weight percentage of FAME in the mixture was first calculated, and then the weight percentage of FAME in the mixture was determined by gas chromatography.

[0099] Then, the high performance liquid chromatogram of the mixture obtained by the above-mentioned qualitative determination method is used to obtain the weight percentage content of fatty acid methyl ester in the mixture through the chromatographic peak of the fatty acid methyl ester. After multiple parallel detections, the detection data of each time are compared with the weight percentage content of fatty acid methyl ester obtained by detection using an existing gas chromatography method. At the same time, the relative standard deviation and recovery rate of the multiple fatty acid methyl ester weight percentage content data of the parallel detection are calculated. When the relative standard deviation and recovery rate indicators meet the requirements, it can be determined that the waste edible oil or its recycled product detection device used can be used for quantitative detection of fatty acid methyl ester contained in the waste edible oil or its recycled product;

[0100] The acid value of the mixture is determined using the acid-base titration method known in the art, and the weight percentage of the fatty acids is calculated using a lauric acid molecular weight of 200, a palmitic acid molecular weight of 256, or an oleic acid molecular weight of 282. A high-performance liquid chromatogram of the mixture obtained using the qualitative determination method is then used to determine the weight percentage of the fatty acids in the mixture based on the chromatographic peaks of the fatty acids. Parallel testing is then performed and compared with the weight percentage of the fatty acids determined using the acid-base titration method. The relative standard deviation and recovery rate of the parallel testing data are then calculated to determine whether the waste edible oil or its recycled product detection device can be used for quantitative detection of the fatty acids contained in the waste edible oil or its recycled product.

[0101] Generally, the recovery rate of the quantitative method that can be used for quantitative detection should be 95-105%, and the relative standard deviation RSD of the parallel detection should be ≤2.0%.

[0102] Table 1 shows the weight percentage content data and its standard deviation and relative standard deviation (RSD%) data obtained by using the waste edible oil or its recycled product detection device provided in Example 1 to detect waste edible oil without fatty acid methyl esters after adding fatty acid methyl ester standards, as well as the weight percentage content data of fatty acids and its standard deviation and relative standard deviation (RSD%) data obtained by detection; wherein:

[0103] The amount of waste edible oil without fatty acid methyl esters was 20.0256 g, and the amount of fatty acid methyl ester standard added was 0.2011 g. The weight percentage content of fatty acid methyl esters in the mixture should be 0.99%. The weight percentage content of fatty acid methyl esters was 0.98% as determined by conventional gas chromatography.

[0104] The acid value of the above mixture was determined by conventional acid-base titration method to be 1.87 mgKOH / g. The weight percentage content of fatty acids thereof was approximately 0.67% based on a lauric acid molecular weight of 200, the weight percentage content of fatty acids based on a palmitic acid molecular weight of 256, and the weight percentage content of fatty acids based on an oleic acid molecular weight of 282, respectively.

[0105] Table 1:

[0106]

[0107] From the above description and the data listed in Table 1, we can see that:

[0108] 1. The detection device and method for detecting waste edible oils and fats or their recycled products provided in Example 1 and this embodiment are used to detect fatty acids and fatty acid methyl esters in waste edible oils and fats, and the repeatability is good, meeting the requirement of relative standard deviation (RSD) ≤ 2.0%;

[0109] 2. The data obtained by detecting the fatty acid content in waste edible oils and fats using the waste edible oil and fat or its recycled product detection device and detection method provided in Example 1 and this embodiment is at the middle value of the acid-base titration result (i.e., the middle value calculated based on the low molecular weight lauric acid and the high molecular weight oleic acid), which is equivalent to the weight percentage content of fatty acids based on the molecular weight of palmitic acid;

[0110] 3. In this test, the theoretical weight percentage content of fatty acid methyl ester should be 0.99%. Using the waste edible oil or its recycled product detection device and detection method provided in Example 1 and this embodiment, the weight percentage content of fatty acid methyl ester measured was 0.98%, and the recovery rate was 98%, which met the recovery rate requirement of 95% to 105%.

[0111] In addition, experiments have shown that the above method can be used to obtain basically the same test data and test results by using common recycled products of waste edible oils and fats without fatty acid methyl esters, including recycled products such as raw materials for making paints, soaps, plasticizers, and bio-emulsifiers, biodiesel, etc. Therefore, the waste edible oil or its recycled product detection device provided in Example 1 and this embodiment can be used for quantitative detection of fatty acid methyl esters and fatty acids contained in waste edible oils and fats or its recycled products.

[0112] like Figure 6 The embodiment of the present invention provides a 20.0250g waste edible oil sample and its components of the high performance liquid chromatogram and Figure 7 for Figure 6 The enlarged view of the part is shown as follows:

[0113] In a 20.0250g waste edible oil sample, the components detected by the waste edible oil or its recycled product detection device provided in Example 1 and this embodiment can be seen as follows:

[0114] In the HPLC chromatogram of the sample, the retention time of triglyceride was 18.995 min, the retention time of diglyceride was 19.606 min, the retention time of monoglyceride was 20.799 min, the retention time of fatty acid was 21.445 min, and the retention time of fatty acid methyl ester was 21.904 min;

[0115] The above retention times are compared with the standard times of triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters, and fall within the acceptable error range of the corresponding standard times. Therefore, it can be determined that the detected substances represented by these chromatographic peaks are the same substance as the test standards corresponding to the standard times;

[0116] At the same time, according to the quantitative detection method of fatty acids and fatty acid methyl esters contained in the above-mentioned waste edible oils or their recycled products, it can be obtained that the weight percentage of fatty acids contained in the sample should be 0.88% based on the molecular weight of palmitic acid, and the weight percentage of fatty acid methyl esters contained should be 0.98%.

[0117] In summary, we can see that:

[0118] First, the present invention provides a high-performance liquid chromatography detection system capable of detecting waste edible oils or their recycled products, which is constructed by a quantitative loop, a sample injector, a pump, a specially selected filling column, a detector, and a recorder. Utilizing this system, not only can the qualitative and quantitative detection of fatty acids and fatty acid methyl esters in waste edible oils or their recycled products be combined, but it can also further expand the detection of other components in the waste edible oils or their recycled products. This not only improves detection efficiency and detection accuracy, provides more high-quality detection items and detection data for waste edible oils or their recycled products, but also reduces the maintenance cost of the detection equipment, reduces detection fees, and provides better services for the recycling and utilization of waste edible oils.

[0119] Secondly, the present invention not only provides a new device and method for detecting waste edible oils and fats or their recycled products, but more importantly, it provides a new idea and method for detecting waste edible oils and fats or their recycled products, opens up a new application research field for high-efficiency size exclusion chromatography, and provides a normalized detection method for different detection items of oil and fat products. Therefore, it is extremely pioneering and creative, and has milestone significance in the field of oil and fat product detection.

[0120] Again, the technical solution of the present invention is unique and ingenious, and the actual operation is simple and convenient. It can not only obtain test results quickly and accurately, but also ensure that the detection equipment works stably for a long time, reduce detection costs, simplify detection operations, reduce maintenance time and maintenance costs, and improve detection efficiency and detection accuracy. Therefore, it has great value for promotion and application.

[0121] In the description of the above manual:

[0122] The terms "this embodiment", "an embodiment of the present invention", "as shown in", "further", etc., mean that the specific features, structures, materials or characteristics described in the embodiment or example are included in at least one embodiment or example of the present invention;

[0123] In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials or characteristics described may be combined or combined in any appropriate manner in any one or more embodiments or examples;

[0124] In addition, those skilled in the art may combine or combine different embodiments or examples and features of different embodiments or examples described in this specification without causing any contradiction.

[0125] Finally, it should be noted that:

[0126] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Non-essential improvements, adjustments or replacements made by those skilled in the art based on the contents of this specification are all within the scope of protection required by the present invention.

Claims

1. A method for detecting waste edible oils and fats or their recycled products using a detection device for waste edible oils and fats or their recycled products, characterized by: The waste edible oil or its regenerated product detection device comprises a high performance liquid chromatography detection system consisting of a quantitative loop, an injector, a pump, a chromatographic column, a detector and a recorder, wherein: The chromatographic column is composed of three 300 mm × 7.5 mm stainless steel columns connected in series. The fillers of the stainless steel columns are porous gel particles made of styrene-divinylbenzene copolymer. The particle size of the gel particles is 5 μm and the pore sizes are 50 Å, 100 Å and 500 Å, respectively. The stainless steel column filled with the gel particles with a pore size of 50 Å constitutes a first filling column, which is connected to the pump; the stainless steel column filled with the gel particles with a pore size of 500 Å constitutes a third filling column, which is connected to the detector; the stainless steel column filled with the gel particles with a pore size of 100 Å constitutes a second filling column, and the two ends of the second filling column are respectively connected to the first filling column and the third filling column. The detector is a differential refractive index detector; The detection method includes the steps of assembling a detection device, determining detection conditions, preparing a standard sample solution, determining a standard time and a standard area, preparing a test sample, and determining the substance detected in the test sample and its content, wherein: The assembly of the detection device includes combining the quantitative loop, the sample injector, the pump, the chromatographic column, the detector, and the recorder to form a high performance liquid chromatography detection system for detecting waste edible oils and fats or their recycled products; Determination of the detection conditions includes determination of the flow rate of the pump, the column temperature of the chromatographic column, the operating temperature of the detector, the capacity of the quantitative loop and the type of mobile phase; The preparation of the standard sample solution comprises taking a test standard of components that may be contained in waste edible oils and fats or their regenerated products, dissolving and diluting the test standard with tetrahydrofuran, dehydrating and drying the test standard with a desiccant, and filtering the test standard; Determining the standard time and standard area includes taking the standard sample solution, passing it through the quantitative loop and the injector, and then injecting it into the waste edible oil or its recycled product detection device with determined detection conditions; after the detector detects and the recorder records the chromatographic peak of the standard sample solution, defining the retention time of the chromatographic peak of the standard sample solution as the standard time of the same component substance as the inspection standard contained in the waste edible oil or its recycled product; and defining the chromatographic peak area corresponding to the content of the standard sample solution that meets the recovery rate standard and the relative standard deviation requirements as the standard area; The preparation of the sample to be tested includes taking waste edible oil or its regenerated product, dissolving and diluting it with tetrahydrofuran, dehydrating and drying it with the same desiccant as used to dry the standard sample solution, and filtering it to obtain the sample solution to be tested; The determination of the detected substance and its content in the test sample includes taking the test sample liquid and performing the same high performance liquid chromatography test on the test sample liquid according to the same process and method as the steps for determining the standard time and standard area, and after the detector detects and the recorder records all chromatographic peaks of the test sample liquid, comparing the retention time and chromatographic peak area of each chromatographic peak of the test sample liquid with the standard time and the standard area, wherein: If the retention time of a chromatographic peak in the sample solution falls within the error range of a certain standard time, it is determined that the detected substance represented by the chromatographic peak and the test standard corresponding to the standard time are the same substance; The chromatographic peak area of the sample liquid determined to be the same substance is compared with the standard area corresponding to the same substance, and the content of the detected substance in the waste edible oil or its recycled product can be calculated based on the sampling amount; The flow rate of the pump is 0.8±0.05 mL / min, the column temperature of the chromatographic column is 35±0.5°C, the operating temperature of the detector is 35±0.5°C, the capacity of the quantitative loop is set to 10±0.5 μL, and the mobile phase is tetrahydrofuran; The test standards are triglycerides, diglycerides, monoglycerides, fatty acids and fatty acid methyl esters.

2. The detection method according to claim 1, wherein: In the step of preparing the standard sample solution, the sampling amount of the test standard is 0.5±0.05g.

3. The detection method according to claim 1, wherein: The desiccant is anhydrous sodium sulfate.

4. The detection method according to claim 1, wherein: The deviation range of the standard time is ±5%min of the standard time.

5. The detection method according to claim 1, wherein: The standard area should meet the recovery rate standard of 95-105%, and the relative standard deviation requirement should be RSD≤2.0%.

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