CN115128199A

CN115128199A - Method for detecting furfural compounds in suction head type microextraction injection and oral liquid

Info

Publication number: CN115128199A
Application number: CN202210872139.XA
Authority: CN
Inventors: 施念
Original assignee: First Affiliated Hospital of Zhengzhou University
Current assignee: First Affiliated Hospital of Zhengzhou University
Priority date: 2022-07-22
Filing date: 2022-07-22
Publication date: 2022-09-30

Abstract

The invention discloses a method for detecting furfural compounds in a suction head type microextraction injection and oral liquid, which is characterized in that an oily extraction solvent dissolved with a derivatization reagent is added on an internal fibrous filler, then a sample solution is sucked in a sucking and beating mode, and the derivatization and extraction processes are synchronously carried out. Then adding desorption solvent to the internal fiber filler in a multi-sucking mode, and finally detecting and analyzing the obtained desorption liquid containing the analyte derivative. The method has the advantages of good extraction effect, stable recovery rate, capability of meeting the requirement of rapid treatment and analysis under certain conditions, and strong development potential. Compared with other analysis and detection methods, the method has the advantages of good sensitivity and selectivity, simple experiment operation and low cost, and can realize rapid and automatic extraction and analysis.

Description

Method for detecting furfural compounds in suction head type microextraction injection and oral liquid

Technical Field

The invention belongs to the field of drug detection and analysis, and relates to a method for detecting furfural compounds in suction head type micro-extraction injection and oral liquid.

Background

5-hydroxymethylfurfural (5-HMF), furfural (F), 5-methylfuran-2-aldehyde (MF) are compounds formed during storage of sugar-containing samples and are often considered to be a sign of quality deterioration due to excessive heating or poor storage conditions. Furfural may also be formed during the manufacture and storage of pharmaceutical products, such as glucose injection, as the major thermal decomposition product of 5-HMF during sterilization and storage. Studies have reported that the intake of 5-HMF in excess of the prescribed dose constitutes a potential risk to human health, e.g. 5-HMF can form adducts with amino acids to produce cytotoxicity. Furthermore, 5-HMF and its oligomers are potentially neurotoxic to animals and humans, especially during neurodevelopment in infants and young children. The world health organization and the european union food code committee set the maximum amount of 5-HMF in honey to 40mg/kg to ensure that the product deteriorates without heating during processing. Currently, there are more and more studies showing that the intake of too much 5-HMF may be a health hazard. Therefore, it is necessary to establish an appropriate method for measuring the content of 5-HMF in sugar-containing medicines such as injections and oral liquids and foods.

At present, a plurality of methods are available for detecting furfurals, namely De Andrad Jucimara and the like detect 5-HMF of sugar-containing foods such as biscuits and breads through High Performance Liquid Chromatography (HPLC), and Jiaqi Shi and the like detect 5-HMF in milk products through liquid chromatography and mass spectrometry (LC-MS). Viviane Maria Rizelio et al performed 5-HMF measurements in honey by the micellar electrokinetic capillary chromatography (MEKC) method. Although the furfural substances can be directly detected by using HPLC, other impurity peaks are easy to interfere at 284nm ultraviolet absorption, so that the quantitative accuracy is influenced.

The reasons influencing the accuracy of furfural detection also include the complexity of detecting the coexisting matrix in the actual sample, and the complex matrix can interfere with the determination of the target analyte, so that the extraction of the target analyte by using an effective pretreatment technology is very necessary. In recent years, analytical methods for extracting 5-HMF from complex matrices are diversified, and mainly include liquid phase extraction, solid phase extraction, liquid phase micro-extraction, solid phase supported liquid phase extraction, membrane micro-extraction and the like. The traditional liquid phase extraction method is time-consuming and labor-consuming, and a large amount of organic solvent is consumed in the extraction process. However, homogeneous liquid-liquid extraction (HLLE) has become one of the most common methods for sample preparation due to its simplicity of operation, rapidity, low consumption of organic solvents, and the like. Wenbin Chen et al established a salting-out assisted liquid-liquid extraction method for the determination of 5-HMF in honey samples, but this process is relatively cumbersome and requires a series of steps such as mixing vortexes and high speed centrifugation. Solid Phase Extraction (SPE) is also commonly used for extraction and concentration. However, the traditional solid phase extraction can not realize high-efficiency extraction, and has the disadvantages of complex operation and high cost.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for detecting furfural compounds in suction head type micro-extraction injection and oral liquid, which has the characteristics of simple steps and high detection precision.

The purpose of the invention is realized by adopting the following technical scheme:

a method for detecting furfural compounds in suction head type micro-extraction injection and oral liquid comprises the following steps:

(1) loading an internal fiber filler into a suction head type extraction device, and then loading an extraction solvent dissolved with a derivatization reagent on the internal filler;

(2) loading injection or oral liquid on the internal fiber filler obtained in the step (1), and adding a desorption solvent into the extraction device to obtain desorption liquid containing the analyte derivative;

(3) and (3) detecting and analyzing the desorption solution containing the analyte derivative obtained in the step (2).

Further, the injection is a traditional Chinese medicine injection or a sugar-containing injection, and the oral liquid is a sugar-containing oral liquid.

Further, the internal filler is kapok fiber, and the adding proportion of the kapok fiber to the injection or the oral liquid is 1-5 mg: 1 mL.

Further, in the step (1), the derivatization reagent is 2, 4-dinitrophenylhydrazine, and the extraction solvent is one or more selected from ethyl acetate, toluene, dichloromethane and chloroform.

Further, the volume ratio of the ethyl acetate to the toluene is 0.25-3: 1.

Further, the addition ratio of the derivatization reagent to the extraction solvent is 0.1-10 mg: 1 mL.

Further, the loading process in the step (2) is that the injection or the oral liquid is sucked and beaten on the internal fiber filler for a plurality of times;

the process of adding the desorption solvent is to suck the desorption solvent on the internal filler a plurality of times.

Further, the desorption solvent in the step (3) is one of methanol, acetonitrile, ethanol and acetone.

Further, the furfural compound is 5-hydroxymethyl furfural, 5-methyl-2-furfural or furfural.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method for detecting furfural compounds in suction head type microextraction injection and oral liquid, which is characterized in that an extraction solvent dissolved with a derivatization reagent is added to an internal fiber filler, and then the injection or the oral liquid is loaded on the internal fiber filler in the step (1) by multiple times of suction beating, so that the derivatization and extraction processes are carried out synchronously. Then, a desorption solvent is added to the internal filler in a multi-suction mode, and finally, the desorption liquid containing the analyte derivative is obtained for detection and analysis. The method has the advantages of good extraction effect, stable recovery rate, capability of meeting rapid processing analysis under certain conditions, and strong development potential. Compared with other analysis and detection methods, the method has the advantages of good sensitivity and selectivity, simple experiment operation and low cost, and can realize rapid and automatic extraction and analysis.

Drawings

FIG. 1 is a feasibility analysis HPLC-UV chromatogram of example 1 and comparative examples 1-2 of the present invention;

FIG. 2 is a graph showing the results of detection of different types of extractants in example 2 of the present invention;

FIG. 3 is a graph showing the results of measurements taken at different volume ratios of ethyl acetate to toluene in the extractant of example 2 in accordance with the present invention;

FIG. 4 is a graph showing the results of testing kapok fibers according to different amounts of additives in example 3 of the present invention;

FIG. 5 is a graph showing the results of measurements performed with different amounts of derivatizing agent in example 4 of the present invention;

FIG. 6 is a graph showing the results of measurements corresponding to different formic acid contents in example 5 of the present invention;

FIG. 7 is a graph showing the results of measurements performed with different desorption solvents in example 6 of the present invention;

FIG. 8 is a graph showing the results of measurements made with different amounts of desorption solvent in example 7 of the present invention;

FIG. 9 is a graph showing the results of the measurements corresponding to the number of times of sample application and suction performed in example 8 of the present invention;

FIG. 10 is a graph showing the results of the desorption/desorption cycles in example 9;

FIG. 11 is a schematic diagram of a detection process according to an embodiment of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

Example 1

The establishment of the model for detecting the furfural compounds by suction head type microextraction comprises the following steps:

(1)：

(1.1) preparation of a tip type micro-extraction device: the extraction device is assembled by a 200 mu L pipette tip and a 1000 mu L pipette tip, 3.00mg of kapok fiber is accurately weighed in the 200 mu L pipette tip, the tip of the 1000 mu L pipette tip is cut off at a proper position, and the 1000 mu L pipette tip is connected with the top of the 200 mu L pipette tip, so that the tip type micro-extraction device is prepared. The kapok fiber will be stuck in the middle and lower part (below the joint) of the combined suction head, thereby avoiding the kapok fiber moving up and down along with the solution in the subsequent sample solution and desorption liquid suction process.

(1.2) preparation of an analyte standard solution: precisely weighing appropriate amounts of 5-HMF (5-hydroxymethylfurfural), F (furfural) and MF (5-methyl-2-furfural) by using a one-hundred-ten-thousand balance, respectively placing the appropriate amounts in different EP tubes, adding analytically pure acetonitrile, carrying out vortex mixing to prepare a stock solution with the mass concentration of 5mg/mL, and transferring the stock solution into an ampoule bottle for later use; respectively sucking appropriate amount of the above 3 aldehyde stock solutions, adding a certain amount of ultrapure water, adding 0.1% formic acid by volume ratio to obtain 10 μ g/mL mixed standard solution (containing 0.1% formic acid), and placing in a refrigerator at 4 deg.C for use.

(1.3) pretreatment of the sample solution: formic acid with the volume ratio of 0.1 percent is directly added into samples such as injection, oral liquid and the like for standby.

(1.4) preparation of derivatization reagent solution: according to the invention, micro-extraction and derivatization are carried out simultaneously, and Ethyl Acetate (EA) is selected as an extraction solvent according to the solubility of 2, 4-Dinitrophenylhydrazine (DNPH). Accurately weighing a proper amount of DNPH, adding analytically pure ethyl acetate, uniformly mixing by vortex, and preparing into a derivatization reagent solution with the mass concentration of 1 mg/mL. Because ethyl acetate has volatility and the concentration of the derivatization reagent is easy to change, the mixture is sealed by a sealing film and stored in a refrigerator at 4 ℃.

(2) Carrying out suction head type micro-extraction: accurately sucking 12.5 mu L of derivatization reagent solution obtained in the step (1.4) to load on an internal fiber filler, namely kapok fiber, assembling a prepared extraction device by adopting a pipette, sucking 1.0mL of mixed standard solution (containing 0.1% of formic acid) or sample solution (containing 0.1% of formic acid) by pressing/loosening a pipette press rod in the sample loading process, repeatedly and slowly sucking for 20 times, simultaneously finishing derivatization and extraction in the process, finally accurately sucking 200 mu L of methanol (MeOH) by using the pipette for desorption, repeatedly desorbing and sucking for 15 times, and directly carrying out HPLC-UV detection on the obtained desorption solution containing the analyte derivative.

(3) And (3) detection: an Agilent 5Tc-C18 column, type 4.6mm X150 mm, 5 μm, mobile phase A: ultrapure water, mobile phase B: chromatographic grade methanol, isocratic elution, a: b is 30: 70(v/v), the column temperature was controlled at 25 ℃, the sample injection amount was set to 10. mu.L, the flow rate was set to 1.0mL/min, and the wavelength of the ultraviolet detector was set to 360 nm.

The molar ratio of the analyte derivative to the analyte is 0.9-1:1 through multiple tests.

To verify the feasibility of the experimental protocol, each experiment was repeated 3 times, as follows.

Comparative example 1

Comparative example 1 differs from example 1 in that: comparative example 1 is a blank derivatisation extraction, in particular the sample solution from example 1 was replaced with pure water (containing 0.1% formic acid).

Comparative example 2

Comparative example 2 differs from example 1 in that: comparative example 2 is a direct derivatization experiment, i.e., the analyte standard solution was directly mixed with the derivatization solution, and the resulting derivative solution was directly analyzed and detected without extraction by the extraction device of the present invention. Specifically, the steps (1) and (2) in example 1 were omitted, and 12.5. mu.L of the derivatization reagent solution obtained in step (1.2) was directly added to 1.0mL of the analyte standard solution obtained in step (2), mixed and vortexed for 30 seconds, and allowed to stand at room temperature for 30 min.

In order to examine the performance of the suction head type extraction device, the analytes of the standard analyte solution are respectively examined through extraction by the extraction device (example 1), blank derivative extraction (comparative example 1) and extraction without the extraction device (comparative example 2), and as shown in fig. 1, fig. 1 is a feasibility analysis HPLC-UV chromatogram of example 1 and comparative examples 1-2. The result shows that the detection method can detect all target analytes, the blank control does not have peaks interfering with the analytes, three groups of parallel experiments are carried out to investigate repeatability, and RSD is within 10 percent, so that the extraction device provided by the research can be effectively used for sample pretreatment.

Example 2

This example differs from example 1 in that: the extraction solvents ethyl acetate in step (1.2) were adjusted to toluene (EB), dichloromethane (MB), and chloroform (TCM), respectively, and the rest of the procedure was the same as in example 1.

The detection result is shown in fig. 2, the effect of extracting 5-HMF from ethyl acetate and toluene is equivalent, and the effect of extracting F and MF from toluene is the best, probably because ethyl acetate has weak polarity, and the nonpolar nature of derivatized F and MF is greater than that of 5-HMF, so that the solubility of F and MF in nonpolar toluene is high, and the effect of extracting with toluene is better.

According to the results, the extraction solvent ethyl acetate was adjusted to a mixed solvent of ethyl acetate and toluene, wherein the volume ratio of ethyl acetate to toluene was 75:25, 50:50, 20:80, respectively. The rest of the procedure was the same as in example 1.

The detection result is shown in fig. 3, and the result shows that the extraction effect is improved to a certain extent by using the mixed solvent of ethyl acetate and toluene as the extraction solvent compared with the effect of using a single extraction solvent.

Example 3

The present example differs from example 1 in that: the procedure of example 1 was repeated except that the amounts of kapok fibers used in step (1.1) of example 1 were adjusted to 1mg, 2mg, 2.5mg, 4mg and 5mg, respectively, the addition amount of the derivatization reagent was 12.5. mu.L, and the volume of the standard solution was 1mL, and the procedure was the same as in example 1.

As shown in FIG. 4, when the addition amount of the derivatization reagent is 12.5. mu.L and the standard solution is 1mL, the dosage of the kapok fiber is more than 2mg, which is helpful to increase the recovery rate of the analyte.

Example 4

This example differs from example 1 in that: the amounts of the derivatizing agents used in step (2) of example 1 were adjusted to 5. mu.L, 7.5. mu.L, 10. mu.L, 15. mu.L, 20. mu.L and 25. mu.L, respectively, and the rest was the same as in example 1.

As shown in FIG. 5, the recovery rate of the 5-HMF derivatized product increased gradually as the amount of the derivatization reagent increased. The extraction efficiency was highest when the amount of derivatizing agent was 15 μ L, however, the extraction recovery decreased sharply when the amount of derivatizing agent continued to increase. It is likely that, because the amount of kapok fiber is constant, as the amount of derivatizing reagent increases, excess derivatizing reagent may fall off the kapok fiber during the pipetting derivatization/extraction process, resulting in poor extraction.

Example 5

The present example differs from example 1 in that: the volume contents of formic acid in the standard solution of the analyte in the step (1.1) of example 1 were adjusted to 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, respectively, and the rest was the same as in example 1.

The detection result is shown in fig. 6, when the content of formic acid is increased to 1%, the peak area of the generated derivative product reaches the maximum value, and the extraction recovery rate is highest. The reason is that the hydrazone compound generated by the reaction of the aldehyde compound and DNPH is carried out under a slightly acidic condition, and has certain requirements on an acidic environment, and experimental results show that when the pH of the reaction system is adjusted by formic acid, the extraction process is most favorably carried out when the addition amount is 1%.

Example 6

Optimization of desorption solvent type and dosage

This example differs from example 1 in that: the desorption solution in example 1 was adjusted to methanol (MeOH), ethanol (EtOH), Acetonitrile (ACN), and Acetone (AC).

The target analyte is polar and is derivatized to be hydrophobic, so the desorption solvent must satisfy good solubility of the target analyte-derivatized product. As shown in fig. 7, the extraction recovery rate was better when acetonitrile and acetone were used as the desorption solvent.

Example 7

This example differs from example 1 in that: the amounts of methanol used in step (2) of example 1 were adjusted to 100. mu.L, 150. mu.L, 250. mu.L and 300. mu.L, respectively, and the rest was the same as in example 1.

The results are shown in FIG. 8, where the amount of 5-HMF derived product gradually increased as the amount of desorption solution was increased, the recovery rate was also gradually increased, and the extraction efficiency was substantially constant as the amount of desorption solution was 200. mu.L. The dosage of the desorption solution is too small, the target analyte is not completely desorbed, and the extraction efficiency is lower. The consumption of the desorption solution meets the requirement that a larger enrichment factor can be realized by using a smaller amount of desorption solution in the micro-extraction to realize the maximum extraction.

Example 8

This example differs from example 1 in that: the number of pipetting operations for loading in step (2) of example 1 was adjusted to 5, 10, 15 and 30, respectively, and the rest of the procedure was the same as in example 1.

As shown in fig. 9, the recovery rate of extraction gradually increased when the number of times of sample loading and pipetting increased, and reached the highest recovery rate and the extraction efficiency reached almost constant when the sample loading and pipetting reached 20 times. When the pipetting coefficient is low, the derivatization reagent and the extraction reagent cannot be fully contacted with the analyte, so that the target analyte is incompletely derivatized and extracted, and the extraction recovery rate is low.

Example 9

This example differs from example 1 in that: the number of desorption/adsorption times in the step (2) of example 1 was adjusted to 5 times, 10 times, 15 times and 30 times, respectively, and the rest of the procedure was the same as in example 1.

The detection result is shown in FIG. 10, the extraction recovery rate is continuously increased with the increase of the desorption and adsorption times and the increase of the amount of the derivative product, but the increase trend is not obvious, and when the desorption and adsorption times are increased for 15 times, the analyte is basically and completely desorbed.

Experimental example 1

1.1 Linear relationship and detection Limit of the detection method of the invention

5-HMF with water was prepared as a series of solutions of 0.5. mu.g/mL, 1. mu.g/mL, 2. mu.g/mL, 5. mu.g/mL, 10. mu.g/mL, 20. mu.g/mL, F with water was prepared as a series of solutions of 0.1. mu.g/mL, 0.2. mu.g/mL, 1. mu.g/mL, 2. mu.g/mL, 5. mu.g/mL, 10. mu.g/mL, 20. mu.g/mL, MF with water was prepared as a series of solutions of 1. mu.g/mL, 2. mu.g/mL, 5. mu.g/mL, 10. mu.g/mL, 20. mu.g/mL, and analyzed according to the methods of step (2) and step (3) in example 1, the peak areas were recorded (3 sets of each concentration were averaged last averaged), and finally the analyte concentrations were linearly regressed with the average peak areas, and the SNR of 3:1 and 10: 1 respectively calculating a detection Limit (LOD) and a quantification Limit (LOQ), as shown in Table 1, the results show that 5-HMF, F and MF respectively have good linear relations in the concentration ranges of 0.5-20 mu g/mL, 0.1-20 mu g/mL and 1-20 mu g/mL, and R is ² Respectively 0.990, 0.996 and 0.993.

TABLE 1

1.2 precision and accuracy of the detection method of the invention

5-HMF, F and MF are prepared into three mass concentrations of 1 mu g/mL, 5 mu g/mL and 10 mu g/mL respectively by water, the mass concentrations of the three components are analyzed according to the methods of the step (2) and the step (3) in the example 1 (each concentration is 3 groups in parallel), the peak areas are recorded, the precision is calculated according to the peak areas, the peak areas are brought into respective standard curves for calculation accuracy, as shown in the table 4, the results show that the accuracy ranges from 84% to 116% respectively, and the RSD ranges from 10% respectively.

TABLE 2

Experimental example 2

The detection method of the furfural compounds in the injection and the oral liquid comprises the following steps: 1mL of the actual injection or oral liquid sample is taken, 1 μ L of formic acid is added, and the mixture is mixed uniformly to obtain 1mL of sample solution containing 0.1% formic acid, and then the sample solution is treated and detected according to the steps (2) and (3) in the example 1, wherein the detection schematic diagram is shown in FIG. 11.

As shown in Table 3, 5-HMF was detected in each of the 5% glucose injection, qingkailing injection, shuanghuanglian injection and zinc gluconate oral liquid, while the other two furfural (F and MF) were not detected.

TABLE 3

Sample (I)	5-HMF(μg/mL)	F(μg/mL)	MF(μg/mL)
				5% glucose injection	0.33	N.D.	N.D.
Qingkailing injection	0.01	N.D.	N.D.
				Shuanghuanglian injection	9.21	N.D.	N.D.
Zinc gluconate oral solution	3.77	N.D.	N.D.

In some application scenes, the detection method can also be used for detecting furfural substances in food, such as apple juice, mixed fruit and vegetable beverage and honey.

Wherein the preparation process of the sample is as follows:

apple juice: accurately weighing 500 mu L of apple juice sample, adding 1 mu L of formic acid, and uniformly mixing to obtain 1mL of sample solution containing 0.1% of formic acid.

50% of mixed fruits and vegetables: mu.L of apple juice sample is added with 1 mu.L of formic acid and mixed evenly to obtain 1mL of sample solution containing 0.1% of formic acid.

Honey sample: accurately weighing 0.1g (accurate to 0.01g) of honey sample, sucking ultrapure water by a pipette to dilute the honey to 1mL, adding 1 μ L formic acid, and uniformly mixing to obtain 1mL sample solution containing 0.1% formic acid.

The detection process was as described in example 1, step (2) and step (3).

As shown in Table 4, 5-HMF was detected in honey at a level of 0.86. mu.g/mL, which corresponds to 0.43mg/kg, calculated at a concentration of 200. mu.g/mL based on honey sample preparation, and did not exceed the maximum limit of 5-HMF in international standard honey of 40 mg/kg. F is detected in both apple juice and honey, which indicates that the method can be used for measuring the content of 5-HMF and F in the actual sugar-containing solution sample.

TABLE 4

Sample (I)	5-HMF(μg/mL)	F(μg/mL)	MF(μg/mL)
				Apple juice	N.D.	0.97	N.D.
50% mixed fruit and vegetable beverage	N.D.	N.D.	N.D.
				Honey	0.86	0.99	N.D.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.

Claims

1. A method for detecting furfural compounds in suction head type micro-extraction injection and oral liquid is characterized by comprising the following steps:

(1) loading an internal fiber filler into a suction head type extraction device, and then loading an oily extraction solvent dissolved with a derivatization reagent on the internal filler;

(3) and (3) detecting and analyzing the desorption solution containing the analyte derivative obtained in the step (2) to obtain the content of the analyte.

2. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 1, wherein the injection is a Chinese medicinal injection or an injection containing sugar, and the oral liquid is an oral liquid containing sugar.

3. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 1, wherein the internal fiber filler is kapok fiber, and the adding ratio of the kapok fiber to the injection or oral liquid is 1-5 mg: 1 mL.

4. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 1, wherein the derivatization reagent in step (1) is 2, 4-dinitrophenylhydrazine or pyrenebutyrylhydrazine, and the oily extraction solvent is one or more selected from ethyl acetate, toluene, dichloromethane and trichloromethane.

5. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 4, wherein the volume ratio of ethyl acetate to toluene is 0.25-3: 1.

6. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 4, wherein the addition ratio of the derivatization reagent to the oily extraction solvent is 0.1-10 mg: 1 mL.

7. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 4, wherein the loading process in the step (2) is to suck the injection or oral liquid on the internal fiber filler for multiple times;

the process of adding the desorption solvent is to suck the desorption solvent on the internal fiber filler for a plurality of times.

8. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 1, wherein the desorption solvent in the step (3) is one of methanol, acetonitrile, ethanol and acetone.

9. The method for detecting furfural compounds in tip type micro-extraction injection and oral liquid according to claim 1, wherein the furfural compounds are one or more of 5-hydroxymethylfurfural, 5-methyl-2-furfural or furfural.