Sampling device for content of growth regulator in fruits and synchronous sampling detection method

Abstract

The invention discloses a sampling device for the content of a growth regulator in fruits and a synchronous sampling detection method, and aims to establish a rapid, simple, safe, reliable and high-specificity sampling detection method for multi-component PGRs in plant-derived food, improve the detection efficiency and reduce the detection cost, and by establishing a QuEChERS sample pretreatment method and combining an HPLC-MS detection technology, the content of a growth regulator in the fruits can be detected, and the content of the growth regulator in the fruits can be detected. According to the present invention, the combination of MgSO4, PSA, C18 and other purification materials is optimized, the PGRs residue rapid detection is performed in the fruit agricultural product matrix, the reference basis is provided for the related food quality safety supervision work such as multi-component PGRs residue detection, risk evaluation, standard formulation and the like, the sampling device can achieve the multi-point rapid equivalent sampling when the fruit is sampled, and the sampling efficiency is improved. Errors caused by manual sampling can be avoided, so that the detection result is more objective and accurate, and the operation is simple and convenient.

Description

Technical Field

[0001] This invention discloses a sampling device and a simultaneous sampling and detection method for the content of growth regulators in fruits, belonging to the field of agricultural product testing technology. Background Technology

[0002] Plant growth hormones and regulators (PGRs) are diverse, with low residue levels and complex matrices, making detection challenging. Commonly used detection methods include gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), HPLC-tandem mass spectrometry (HPLC-MS / MS), and ion chromatography. Among these, HPLC-MS / MS offers advantages such as low detection limits, minimal matrix interference, speed, and accuracy, making it the most widely used method in national standards. Currently, four common PGRs are gibberellic acid, 6-benzylaminopurine, chlorpyrifos, and thiamethoxam. While all four PGR standards can be detected using HPLC-MS / MS, their different standards, requiring varying pretreatment methods and detection conditions, present significant inconveniences for multi-component PGR detection in the same sample. Furthermore, manual sampling of fruit pulp is necessary, and repeated sampling makes it difficult to ensure equal sample volumes, potentially affecting the accuracy of the results. Summary of the Invention

[0003] The purpose of this invention is to solve the problems in the prior art by providing a sampling device and a simultaneous sampling and detection method for the content of growth regulators in fruits.

[0004] The present invention achieves the above-mentioned objective through the following technical solution: a sampling device for the content of growth regulators in fruit, comprising a base, a fixed seat, a sampling mechanism, and a stoppered centrifuge tube. The fixed seat is located at the center of the base, and an insertion rod for fixing the fruit is provided at the center of the fixed seat. The sampling mechanism is provided in four sets, and the sampling mechanism includes a rotating platform, a mounting base, a sampling component, and a driving component. The mounting base is fixed on the rotating platform, and the sampling component is slidably disposed with respect to the mounting base. The driving component is disposed on the mounting base and is used to drive the sampling component to slide. The four rotating platforms are symmetrically distributed around the fixed seat, and a support base is provided between two adjacent rotating platforms. A power component for driving the rotating platform to rotate 90° is provided on the support base. The stoppered centrifuge tube is mounted on the base, and the stoppered centrifuge tube is located directly below the sampling tube in a vertical state.

[0005] Preferably, the sampling assembly includes a sliding tube, a sampling tube, a limiting bolt, a first spring, and a pushing member. One end of the sampling tube is embedded in the sliding tube, and a first protrusion is provided on the outer side of the sampling tube. Two second protrusions are provided on the end of the sliding tube near the sampling tube. One end of the limiting bolt passes through the second protrusions and is fixedly connected to the first protrusion. The first spring is sleeved on the outer side of the limiting bolt, and the first spring applies a force to the sampling tube away from the sliding tube. The pushing member is installed inside the sampling tube and the sliding tube and is used to push the sampled fruit sample out of the sampling tube. A limiting seat corresponding to the position of the sampling tube is provided on the fixing seat. An oblong hole is provided on the limiting seat, and an adjusting bolt is provided in the oblong hole. The adjusting bolt is threadedly connected to the fixing seat.

[0006] Preferably, the pushing component includes a sliding rod and a second spring. The sliding rod has a stepped shaft structure, with one end of its smaller diameter embedded in the sampling tube and the other end located inside the sliding tube. The second spring is sleeved on the outside of the sliding rod and applies a force to the sliding rod against the sliding tube. The end of the sliding rod away from the sampling tube is connected to an air supply assembly. The air supply assembly includes an air guide tube, a solenoid valve, and an air pump. The solenoid valve is connected to the air guide tube and the air pump and is used to control the inflation and deflation of the sliding tube.

[0007] Preferably, the drive assembly includes a first motor and a drive gear. The first motor is mounted on the mounting base, and the drive gear is fixed on the output shaft of the first motor. The sliding tube has a limiting part that slides with the mounting base, and the sliding tube is also provided with a plurality of toothed grooves that mesh with the drive gear.

[0008] Preferably, the sampling tube has multiple protruding ridges on the inner side of the end away from the sliding tube, and a channel for fruit samples to pass through is provided between two adjacent protruding ridges. The sampling tube has a sliding groove at the end inside the sliding tube, and the sliding groove includes a horizontal section and an arc-shaped section. A pin is provided between two second protrusions of the sliding rod, and one end of the pin is located in the sliding groove. An arc groove for avoiding the limiting bolt is provided on the second protrusion.

[0009] Preferably, the power assembly includes a second motor, a driving bevel gear, and a driven bevel gear. Multiple driven bevel gears are provided and fixed on both sides of the rotating platform via a rotating shaft. The driven bevel gears on two adjacent rotating platforms mesh and drive each other. The second motor is mounted on a support base. The driving bevel gear is fixed on the output shaft of the second motor and meshes with one of the driven bevel gears.

[0010] A method for simultaneous sampling and detection of plant growth regulator content in fruits, comprising the following steps: Preparation of S1 standard working solution: Prepare 1.0 mg / L standard working solutions of the four PGRs standards with methanol solution for the optimization of mass spectrometry working conditions; Preparation of S2 mixed standard solution: Prepare a series of mixed standard solutions with methanol at concentrations of 5, 10, 25, 50 and 100 ug / L for use in the instrument. S3 Fresh Fruit Sampling: Using a sampling device, multiple equal-volume samples of fresh fruit that do not contain the four PGRs standards are taken, and the sampled fresh fruit samples are placed in stoppered centrifuge tubes for later use. S4 Sample Extraction: Add 10.0 mL of 1% acetic acid-acetonitrile solution to a stoppered centrifuge tube containing fresh fruit samples, then add 2.0 g of NaCl and place in a circular shaker to homogenize at 1800 r / min for 2 min. Then centrifuge at 4500 r / min for 3 min to obtain a blank fruit matrix solution. S5 Sample Purification: Four PGRs standards were prepared into a series of mixed standard solutions with mass concentrations of 0, 5, 10, 25, 50 and 100 ug / L using blank fruit matrix solution. 1.5 mL of the supernatant was transferred into a 2 mL QuEChERS dispersion purification reagent tube, vortexed for 1 min, centrifuged at 12000 r / min for 3 min, and then the supernatant was drawn up with a disposable syringe and filtered through a 0.22 μm organic filter membrane. The filtrate was measured according to the instrument optimization conditions. S6 instrument operating condition optimization: Based on the polarity of the four PGRs, first utilize C 18 If the retention is poor, the component with higher polarity will be selected as the evaluation index to examine its separation effect in other chromatographic columns. For the selection of mobile phase, acetonitrile-water, methanol-water, and methanol-formic acid-water are compared. The mobile phase is determined based on the retention peak shape and response value of the target analyte for subsequent experiments. S7 Matrix Effect Evaluation: Using the blank matrix solution of the tested fruit and a series of standard solutions diluted with methanol, the slope ratio of the matrix standard curve to the methanol standard curve was calculated. The matrix effect ME was evaluated by the ratio, where ME (%) = 100 * (k matrix -k solvent ) / k solvent In the formula, k matrix k is the slope of the standard curve of the matrix. solvent denoted as the slope of the methanol solvent standard curve; when ME > 0, it indicates that the matrix has a matrix-enhancing effect on the analyte; when ME < 0, it indicates that the matrix has a matrix-inhibiting effect on the analyte; when |ME| ≤ 20%, it indicates a weak matrix effect; when 20% < |ME| ≤ 50%, it indicates a moderate matrix effect; when |ME| > 50%, it indicates a strong matrix effect.

[0011] Compared with the prior art, the beneficial effects of the present invention are: 1. By setting up a sampling mechanism, a drive component, and a power component, the insertion rod is inserted into the fruit, and the drive component drives the sampling tube to move horizontally until the sampling tube is inserted into the fruit. The insertion depth of multiple sampling tubes into the fruit is consistent, which can make the quality of the sampled fruit basically the same, thereby simplifying the tedious steps of manual sampling, making the operation simple and convenient, and ensuring that it will not affect the subsequent test results.

[0012] 2. The detection method of this invention optimizes the pretreatment and purification conditions, instrument operation, and detection conditions based on the detection object and target. The linear range, limit of detection, limit of quantitation, and recovery rate of the detection method are verified. Finally, multi-component PGRs are simultaneously determined on actual fruit and agricultural product samples, and the results are analyzed. Optimization of MgSO4, PSA, and C is also performed. 18 By determining the optimal ratio of purification materials, the pretreatment scheme for QuEChERS samples was established. Actual fruit and agricultural product samples were used for pretreatment, and the residual amounts of four PGRs, including gibberellic acid, were simultaneously determined by HPLC-MS. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of a sampling device for measuring the content of growth regulators in fruits according to the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a sampling device for measuring the content of growth regulators in fruits according to the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the sampling mechanism in this invention; Figure 4 This is a schematic diagram of the internal structure of the sampling component in this invention; Figure 5 This is a schematic diagram of the sampling tube in this invention; Figure 6 This is a partial structural schematic diagram of the power component in this invention; Figure 7 This is a schematic diagram illustrating the principle of a simultaneous sampling and detection method for the content of growth regulators in fruits according to the present invention. Reference numerals: 1. Base; 2. Sampling mechanism; 3. Support seat; 4. Plug-filled centrifuge tube; 5. Rotating stage; 6. Sampling tube; 7. Sliding tube; 8. Fixed seat; 9. Power assembly; 10. Mounting seat; 11. Limiting part; 12. Limiting seat; 13. First spring; 14. Limiting bolt; 15. Driving gear; 16. First motor; 17. Toothed groove; 18. Air guide tube; 19. Arc groove; 20. Pin; 21. Second boss; 22. First boss; 23. Second spring; 24. Sliding rod; 25. Protruding ridge; 26. Channel; 27. Horizontal section; 28. Arc section; 29. ​​Second motor; 30. Driving bevel gear; 31. Driven bevel gear; 32. Rotating shaft; 33. Adjusting bolt. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] like Figures 1-6 As shown, a sampling device for the content of growth regulators in fruit includes a base 1, a fixed seat 8, a sampling mechanism 2, and a stoppered centrifuge tube 4. The fixed seat 8 is located at the center of the base 1, and an insertion rod for fixing the fruit is provided at the center of the fixed seat 8. The sampling mechanism 2 is provided in four sets, and the sampling mechanism 2 includes a rotating table 5, a mounting base 10, a sampling component, and a driving component. The mounting base 10 is fixed on the rotating table 5, and the sampling component is slidably disposed with respect to the mounting base 10. The driving component is disposed on the mounting base 10 and is used to drive the sampling component to slide. The four rotating tables 5 are symmetrically distributed around the fixed seat 8, and a support base 3 is provided between two adjacent rotating tables 5. A power component 9 for driving the rotating table 5 to rotate 90° is provided on the support base 3. The stoppered centrifuge tube 4 is installed on the base 1, and the stoppered centrifuge tube 4 is located directly below the sampling tube 6 in a vertical state.

[0016] The sampling assembly includes a sliding tube 7, a sampling tube 6, a limiting bolt 14, a first spring 13, and a pushing member. One end of the sampling tube 6 is embedded in the sliding tube 7, and a first protrusion 22 is provided on the outer side of the sampling tube 6. Two second protrusions 21 are provided on the end of the sliding tube 7 near the sampling tube 6. One end of the limiting bolt 14 passes through the second protrusions 21 and is fixedly connected to the first protrusions 22. The first spring 13 is sleeved on the outer side of the limiting bolt 14, and the first spring 13 applies a force to the sampling tube 6 away from the sliding tube 7. The pushing member is installed inside the sampling tube 6 and the sliding tube 7 and is used to push the sampled fruit sample out of the sampling tube 6. A limiting seat 12 corresponding to the position of the sampling tube 6 is provided on the fixing seat 8, and a waist is provided on the limiting seat 12. An adjusting bolt 33 is installed inside the oblong hole. The adjusting bolt 33 is threadedly connected to the fixed seat 8. When the sampling tube 6 is in a horizontal state, the driving component drives the sliding rod 24 to slide horizontally, and the sliding tube 7 drives the sampling tube 6 to move synchronously, so that one end of the sampling tube 6 is inserted into the fruit. The fruit sample continues to enter the sampling tube 6. When the first protrusion 22 on the sampling tube 6 abuts against the limiting seat 12, the sampling tube 6 can no longer move. Thus, the sampling tube 6 completes the sampling of the fruit sample. By controlling the sliding distance of the sliding tube 7 and the relative distance between the first protrusion 22 and the limiting seat 12, the sampling amount of the fruit sample by the sampling tube 6 can be controlled. The position of the limiting seat 12 on the fixed seat 8 is controlled by the limiting bolt 14.

[0017] The pushing component includes a sliding rod 24 and a second spring 23. The sliding rod 24 has a stepped shaft structure, with its smaller diameter end embedded in the sampling tube 6 and the other end located inside the sliding tube 7. The second spring 23 is sleeved on the outside of the sliding rod 24 and applies a force to the sliding rod 24 against the sliding tube 7. The end of the sliding rod 24 away from the sampling tube 6 is connected to an air supply assembly, which includes an air guide tube 18, a solenoid valve, and an air pump. The solenoid valve is connected to the air guide tube 18 and the air pump and is used to control the inflation and deflation of the sliding tube 7. After the sampling tube 6 completes the sampling of the fruit, the sampled fruit... The sample is located inside the sampling tube 6. After the power component 9 drives the sampling tube 6 to rotate 90°, the sampling tube 6 is kept in a vertical position. Then, the air pump and solenoid valve control the air guide tube 18 to fill the sliding tube 7 with air. The gas pressure pushes the sliding rod 24 to compress the second spring 23. In this way, the sliding rod 24 can push the sampled fruit out of the sampling tube 6, so that the fruit sample falls into the stoppered centrifuge tube 4 for subsequent testing. After the solenoid valve vents the gas in the sliding tube 7, the second spring 23 drives the sliding rod 24 to reset, so that the sampling tube 6 can smoothly carry out the next fruit sampling.

[0018] The drive assembly includes a first motor 16 and a drive gear 15. The first motor 16 is mounted on the mounting base 10, and the drive gear 15 is fixed on the output shaft of the first motor 16. The sliding tube 7 has a limiting part 11 that slides on the mounting base 10, and the sliding tube 7 is also provided with a plurality of toothed grooves 17 that mesh with the drive gear 15. When the first motor 16 drives the drive gear 15 to rotate, the drive gear 15 can drive the sliding tube 7 to slide along the axis of the sliding tube 7 on the mounting base 10 by meshing with the toothed grooves 17. This allows the sampling tube 6 to approach or move away from the fruit, thereby ensuring that the fruit sampling operation can be carried out smoothly.

[0019] The sampling tube 6 has multiple protrusions 25 on its inner side at the end away from the sliding tube 7. A channel 26 for fruit samples to pass through is provided between two adjacent protrusions 25. The end of the sampling tube 6 inside the sliding tube 7 has a groove, which includes a horizontal section 27 and an arc-shaped section 28. A pin 20 is provided between two second protrusions 21 on the sliding rod 24, with one end of the pin 20 located inside the groove. An arc-shaped groove 19 for avoiding the limiting bolt 14 is provided on the second protrusion 21. During fruit sampling, when the first protrusion 22 on the sampling tube 6 abuts against the mounting base 10, the sampling tube 6 cannot move further, while the driving assembly can drive the sliding tube 7 to continue sliding, allowing the sampling tube 6 and the sliding tube 7 to move together. The relative sliding between them causes the sliding tube 7 to drive the pin 20 to move synchronously. In this way, one end of the pin 20 slides in the groove. When the pin 20 slides from the horizontal section 27 to the arc section 28, the pin 20 causes the sampling tube 6 to rotate relative to the sliding tube 7 by a certain angle. The limiting bolt 14 rotates in the arc groove 19. In this way, the sampling tube 6 can drive the convex rib 25 to rotate synchronously. The convex rib 25 first divides the sampled fruit sample into equal parts. Then, when the sampling tube 6 rotates, the convex rib 25 separates the sampled fruit sample from the fruit body. This ensures that when the driving component drives the sampling tube 6 away from the fruit body, the sampled fruit sample will not detach from the sampling tube 6.

[0020] The power assembly 9 includes a second motor 29, a driving bevel gear 30, and a driven bevel gear 31. Multiple driven bevel gears 31 are provided and fixed to both sides of the rotating table 5 via a rotating shaft 32. The driven bevel gears 31 on two adjacent rotating tables 5 mesh and drive each other. The second motor 29 is mounted on the support base 3. The driving bevel gear 30 is fixed on the output shaft of the second motor 29 and meshes with one of the driven bevel gears 31. When the second motor 29 drives the driving bevel gear 30 to rotate, the driving bevel gear 30 drives one of the driven bevel gears 31 to rotate. By relying on the meshing of two adjacent driven bevel gears 31, the four rotating tables 5 can be driven to rotate synchronously, thereby changing the position of the sampling tube 6 so that the sampling tube 6 can be kept in a horizontal or vertical state. In this way, the fruit pulp can be sampled from the surface of the fruit in equal amounts and the pulp can be smoothly placed into the stoppered centrifuge tube 4.

[0021] like Figure 1 and Figure 7 As shown, a method for simultaneous sampling and detection of plant growth regulator content in fruits includes the following steps: Preparation of S1 standard working solution: Prepare 1.0 mg / L standard working solutions of the four PGRs standards with methanol solution for the optimization of mass spectrometry working conditions; Preparation of S2 mixed standard solution: Prepare a series of mixed standard solutions with methanol at concentrations of 5, 10, 25, 50 and 100 ug / L for use in the instrument. S3 Fresh Fruit Sampling: Using a sampling device, multiple equal-volume samples of fresh fruit that do not contain the four PGRs standards are taken. The sampled fresh fruit samples are placed in stoppered centrifuge tubes 4 for later use. S4 Sample Extraction: Add 10.0 mL of 1% acetic acid-acetonitrile solution to the stoppered centrifuge tube 4 containing the fresh fruit sample, then add 2.0 g of NaCl and place it in a circular shaker. Shake at 1800 r / min for 2 min to homogenize. Then centrifuge at 4500 r / min for 3 min to obtain a blank fruit matrix solution. S5 Sample Purification: Four PGRs standards were prepared into a series of mixed standard solutions with mass concentrations of 0, 5, 10, 25, 50 and 100 ug / L using blank fruit matrix solution. 1.5 mL of the supernatant was transferred into a 2 mL QuEChERS dispersion purification reagent tube, vortexed for 1 min, centrifuged at 12000 r / min for 3 min, and then the supernatant was drawn up with a disposable syringe and filtered through a 0.22 μm organic filter membrane. The filtrate was measured according to the instrument optimization conditions. S6 instrument operating condition optimization: Based on the polarity of the four PGRs, first utilize C 18 If the retention is poor, a highly polar component will be selected as the evaluation index to examine its separation effect in other chromatographic columns. For the selection of mobile phase, acetonitrile-water, methanol-water, and methanol-formic acid water will be compared. It should be noted that the formic acid water contains 0.1% formic acid by volume. The mobile phase will be determined for subsequent experiments based on the retention peak shape and response value of the target analyte. S7 Matrix Effect Evaluation: Using the blank matrix solution of the tested fruit and a series of standard solutions diluted with methanol, the slope ratio of the matrix standard curve to the methanol standard curve was calculated. The matrix effect ME was evaluated by the ratio, where ME (%) = 100 * (k matrix -k solvent ) / k solvent In the formula, k matrix k is the slope of the standard curve of the matrix. solventdenoted as the slope of the methanol solvent standard curve; when ME > 0, it indicates that the matrix has a matrix-enhancing effect on the analyte; when ME < 0, it indicates that the matrix has a matrix-inhibiting effect on the analyte; when |ME| ≤ 20%, it indicates a weak matrix effect; when 20% < |ME| ≤ 50%, it indicates a moderate matrix effect; when |ME| > 50%, it indicates a strong matrix effect.

[0022] In this embodiment, in step S5, when the supernatant is added to the QuEChERS dispersion purification reagent tube, the QuEChERS dispersion purification reagent tube contains an optimized and determined combination of purification materials, the specific composition of which is shown in Table 1.

[0023] Table 1 Purification Material Combination Scheme

[0024] In the table, MgSO4 represents magnesium sulfate, PSA represents ethylenediamine-N-propylsilane, and C 18 It is octadecylsilane-bonded silica gel, and GCB is graphitized carbon black.

[0025] HPLC-MS operating conditions optimization: The instrument response values ​​of four PGR single standard solutions were optimized to determine the retention time, precursor ion and corresponding sheath lens voltage, and parameters such as spray voltage, sheath gas pressure and auxiliary gas pressure were optimized to determine qualitative and quantitative ion pairs.

[0026] Investigation of chromatographic column conditions: via C 18 The retention of hormones with relatively poor retention was selected as the evaluation index for the chromatographic column. Chromatographic columns of different polarities from companies such as Thermo Fisher Scientific and Agilent Technologies were screened, and the best separation column was finally selected based on the retention time.

[0027] Investigation of mobile phase: Using the target index as the analyte, different mobile phases were designed. In this embodiment, three were selected, including acetonitrile-water, methanol-water, and methanol-formic acid water. The subsequent mobile phase was finally determined based on the retained peak shape and response value of the target analyte.

[0028] Optimization of pretreatment methods: This invention simultaneously detects and applies the QuEChERS method, designs treatment combinations with different contents of MgSO4, PSA and GCB, adds them to matrix standard mixtures of PGRs with different mass concentrations, investigates the effect of different purification material combinations on the recovery rate of the PGRs compounds to be tested, and finally determines the purification scheme for the test samples.

[0029] Linear range, limit of detection and limit of quantitation, and recovery test of the method: Under optimized pretreatment and detection conditions, a mixed standard working solution was prepared from the purified solution of blank fruit samples and the linear range and correlation coefficient were obtained. The limits of detection and limits of quantitation of four PGRs were further determined. Quantification was performed using matrix-matched standards combined with external standard method. The average recovery rate and RSD were calculated to examine the accuracy and precision of the method.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for sampling the content of growth regulators in fruit, comprising a base (1), a fixing seat (8), a sampling mechanism (2) and a centrifuge tube with plug (4), characterized in that, The fixed seat (8) is located at the center of the base (1), and the center of the fixed seat (8) is provided with an insertion rod for fixing fruits, the sampling mechanism (2) is provided with four groups, and the sampling mechanism (2) comprises a rotating table (5), a mounting seat (10), a sampling assembly and a driving assembly, the mounting seat (10) is fixed on the rotating table (5), the sampling assembly is slidably arranged with the mounting seat (10), the driving assembly is arranged on the mounting seat (10) and is used for driving the sampling assembly to slide, four rotating tables (5) are symmetrically distributed with the fixed seat (8) as the center, and a supporting seat (3) is arranged between adjacent two rotating tables (5), the supporting seat (3) is provided with a power assembly (9) for driving the rotating table (5) to rotate 90°, the plug centrifugal tube (4) is installed on the base (1), and the plug centrifugal tube (4) is located directly below the sampling tube (6) in the vertical state.

2. A device for sampling the content of a growth regulator in a fruit according to claim 1, characterized in that The sampling assembly comprises a sliding tube (7), a sampling tube (6), a limiting bolt (14), a first spring (13) and a pushing piece, one end of the sampling tube (6) is embedded into the sliding tube (7), and the outer side of the sampling tube (6) is provided with a first boss (22), the end of the sliding tube (7) close to the sampling tube (6) is provided with two second bosses (21), one end of the limiting bolt (14) passes through the second boss (21) and is fixedly connected with the first boss (22), the first spring (13) is sleeved on the outer side of the limiting bolt (14), and the first spring (13) applies a force away from the sliding tube (7) to the sampling tube (6), the pushing piece is installed in the sampling tube (6) and the sliding tube (7), and is used for pushing the fruit sample after sampling out of the sampling tube (6), the fixed seat (8) is provided with a limiting seat (12) corresponding to the position of the sampling tube (6), the limiting seat (12) is provided with a waist-shaped hole, the waist-shaped hole is provided with an adjusting bolt (33), and the adjusting bolt (33) is in threaded connection with the fixed seat (8).

3. A device for sampling the content of a growth regulator in a fruit according to claim 2, characterized in that The pushing piece comprises a sliding rod (24) and a second spring (23), the sliding rod (24) is in a stepped shaft structure, one end of the sliding rod (24) with a small diameter is embedded into the sampling tube (6), and the other end is located in the sliding tube (7), the second spring (23) is sleeved on the outer side of the sliding rod (24), and the second spring (23) applies a force to the sliding rod (24) to resist the sliding tube (7), one end of the sliding rod (24) away from the sampling tube (6) is connected with a gas supply assembly, the gas supply assembly comprises a gas guide pipe (18), an electromagnetic valve and a gas pump, the electromagnetic valve is connected with the gas guide pipe (18) and the gas pump, and the electromagnetic valve is used for controlling the inflation and exhaust of the sliding tube (7).

4. A device for sampling the content of a growth regulator in a fruit according to claim 3, characterized in that The driving assembly comprises a first motor (16) and a driving gear (15), the first motor (16) is arranged on the mounting base (10), the driving gear (15) is fixed on the output shaft of the first motor (16), the sliding pipe (7) has a limiting part (11) arranged in sliding mode with the mounting base (10), and a plurality of tooth-shaped grooves (17) engaged with the driving gear (15) are further arranged on the sliding pipe (7).

5. A device for sampling the content of a growth regulator in a fruit according to claim 4, characterized in that A plurality of convex edges (25) are arranged on the inner side of the end of the sampling pipe (6) away from the sliding pipe (7), a passage (26) for the fruit sample to pass through is arranged between two adjacent convex edges (25), the end of the sampling pipe (6) in the sliding pipe (7) has a sliding groove, the sliding groove comprises a horizontal section (27) and an arc section (28), the sliding rod (24) is provided with a latch (20) between the two second convex platforms (21), one end of the latch (20) is located in the sliding groove, and the second convex platform (21) is provided with an arc-shaped groove (19) avoiding the limiting bolt (14).

6. A device for sampling the content of a growth regulator in a fruit according to claim 5, characterized in that The power assembly (9) comprises a second motor (29), a driving bevel gear (30) and a driven bevel gear (31), a plurality of driven bevel gears (31) are arranged on both sides of the rotating table (5) through a rotating shaft (32), the driven bevel gears (31) on the adjacent two rotating tables (5) are engaged and driven, the second motor (29) is installed on the supporting base (3), the driving bevel gear (30) is fixed on the output shaft of the second motor (29), and the driving bevel gear (30) is engaged with one of the driven bevel gears (31).

7. A method for the simultaneous sampling and detection of the content of growth regulators in fruits, using the sampling device according to claim 6, characterized in that, The method comprises the following steps: S1: Preparation of standard working solution: 4 PGRs standard samples are respectively prepared into 1.0 mg / L standard working solution with methanol solution, which is used for optimization of mass spectrometry working condition; S2: Preparation of mixed standard solution: 4 PGRs standard samples are prepared into 5, 10, 25, 50 and 100 ug / L series of mixed standard solutions with methanol; S3: Fresh fruit sampling: using a sampling device, a fresh fruit sample without 4 PGRs standard samples is sampled at multiple points and in equal amounts, and the sampled fresh fruit sample is placed in a centrifuge tube (4) with a plug for standby; S4: Sample extraction: 10.0 mL of 1% acetic acid-acetonitrile solution is added to the centrifuge tube (4) with a plug containing the fresh fruit sample, 2.0 g of NaCl is added, and the mixture is uniformly oscillated in a circular oscillator at 1800 r / min for 2 min, then centrifuged at 4500 r / min for 3 min to obtain a blank fruit matrix solution; S5: Sample purification: 4 PGRs standard samples are respectively prepared into 0, 5, 10, 25, 50 and 100 ug / L series of mixed standard solutions with the blank fruit matrix solution, 1.5 mL of supernatant is taken and placed in a 2 mL QuEChERS dispersion purification reagent tube, then vortexed for 1 min, centrifuged at 12000 r / min for 3 min, then the supernatant is taken with a disposable syringe, filtered with a 0.22 um organic filter membrane, and the filtrate is determined according to the optimized conditions of the instrument; S6 Instrument working condition optimization: according to the polarity of four PGRs, first use C 18 chromatographic column for detection, if the retention is poor, select the more polar component as the index to investigate its separation effect in other chromatographic column; mobile phase selection, compare acetonitrile-water; methanol-water; Methanol-formic acid water, according to the target to be measured object retention peak shape and response value, determine the mobile phase for subsequent test; S7 Matrix effect evaluation: a series of concentrations of standard solution is diluted with the measured fruit blank matrix solution and methanol, respectively, and the slope ratio of the matrix standard curve and the methanol standard curve is calculated to evaluate the matrix effect ME by the ratio, wherein ME (%) = 100*(k matrix -k solvent ) / k solvent , wherein k matrix is the slope of the standard curve of the matrix, and k solvent is the slope of the standard curve of the methanol solvent; when ME>0, it indicates that the matrix has a matrix enhancement effect on the analyte; when ME<0, it indicates that the matrix has a matrix inhibition effect on the analyte; when |ME|≤20%, it indicates that the matrix effect is weak; when 20%<|ME|≤50%, it indicates that the matrix effect is moderate; and when |ME|>50%, it indicates that the matrix effect is strong.

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