CN113358627B - Method for rapidly determining quality components of tea trees in field based on Raman detection - Google Patents

Abstract

The invention discloses a method for rapidly determining tea tree quality components in a field based on Raman detection. The micro-fluidic chip taking the foam copper as the filter element is designed aiming at the pretreatment of the tea, so that the efficiency and the portability of the pretreatment of the tea are greatly improved, in addition, corresponding nano metal materials are provided aiming at different quality components in the tea, the detection accuracy and the high flux are realized, and meanwhile, the portability of the Raman detection device can ensure that the rapid quality analysis can be carried out on the tea trees in real time in the field, so that the development of the specific breeding work of the fruit trees is facilitated.

Description

A method for rapid field determination of tea tree quality components based on Raman detection

technical field

The invention relates to the technical field of tea tree component detection, in particular to a method for rapid field determination of tea tree quality components based on Raman detection.

Background technique

Raman spectroscopy is a kind of molecular vibrational spectroscopy, which is an analytical method for studying the molecules by analyzing the scattering spectra with different frequencies from the incident light to obtain spectral information at the molecular level. Raman spectroscopic detection technology has the advantages of small sample consumption, fast detection speed, and high detection accuracy. It is currently widely used in food safety, drug testing, jewelry identification and other fields. In recent years, with the development of technology, the traditional bulky Raman spectrometer can be hand-held. This hand-held Raman detector is small in size and convenient to use, and has great development space in the field of on-site instant detection.

In the detection of Raman spectroscopy, since the plasmon wave cannot propagate continuously on the surface of the metal nanostructure, the LSPR phenomenon will be generated, which will cause a strong induced electric field, which will significantly increase the Raman scattering signal of the molecules adsorbed on the surface of the metal nanostructure. In the actual detection process, metal ions with different nanostructures are added to enhance the Raman effect.

Microfluidic chip is the use of microelectromechanical processing technology to miniaturize the valves, flow pipes, mixing reactors, heaters, separation devices, detectors and other components involved in the sampling, pretreatment, derivatization, mixing and detection of chemical analysis. A microfluidic system integrated into the chip to realize the detection and analysis of liquid flow. Its advantages of high throughput, easy operation, and high integration make it develop rapidly and have broad application prospects in many fields such as biomedicine, health quarantine, and environmental testing.

Copper foam is a new type of multifunctional material with a large number of connected or disconnected pores evenly distributed in the copper matrix. Due to its unique structural characteristics and harmless characteristics to the human body, it is well used in the fields of medical filtration and water purification.

The invention combines a microfluidic chip, a foamed copper material and a portable Raman detection device, and proposes a detection method for quality components such as caffeine and theanine in tea leaves.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the present invention provides a Raman detection-based method for rapidly determining the quality components of tea trees in the field. The rapid identification of tea tree quality components has a simple method and convenient detection; at the same time, the nano-metal materials used for tea tree quality components have good adaptability, making the detection results accurate.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for quickly determining the quality components of tea trees in the field based on Raman detection, which uses a portable Raman spectrum detection device, a filter chip and a detection chip to cooperate to detect the quality components of a tea sample;

Wherein, the method includes the following steps:

S1, add distilled water after the tea leaves collected are pulverized to obtain tea samples;

S2, take the tea samples obtained in step S1, and inject them into the filter chip through the liquid inlet;

S3, connecting the filter chip in step S2 with the detection chip;

S4, tear off the sealing film at the outlet channel of the filter chip, and the tea sample flows into the detection area of the detection chip through the filter material;

S5. After the filtration, separate the filter chip from the detection chip, and at the same time treat the filter chip for reuse;

S6, put the detection chip into the portable Raman spectrum detection device for sample detection;

S7, the detection result is processed to obtain the component content.

Preferably, the filter chip includes a base, and the base is provided with a liquid inlet, a liquid storage tank, a filter part, and a sealing film in sequence from top to bottom; wherein, the liquid inlet is arranged perpendicular to the base, and the liquid inlet The side wall is provided with a channel that communicates with the liquid storage tank, the upper part of the liquid storage tank is provided with an exhaust hole, the lower part of the liquid storage tank is connected with the filter part, and the filter part is opened at one end away from the liquid storage tank There is an outlet channel, the sealing film is arranged at the lowermost part of the outlet channel, and the bottom of one end of the base close to the outlet channel is arranged with not less than 2 fitting posts.

Preferably, the detection chip includes a fitting hole, a filtrate storage tank and a detection area, the fitting hole is fitted with the fitting column and the number of the two is the same, and is used for the filter chip when the filter chip and the detection chip are vertically connected fixed; the filtrate reservoir is used to store excess filtrate.

Preferably, the wavelength of the laser used for detection by the portable Raman spectrum detection device is 500-800 nm, the laser power is 50-200 mW, and the signal collection time is 1-20 s.

Preferably, a filter material is installed in the filter part for filtering the tea samples.

As a further preferred technical solution of the present invention, the filter material is preferably foamed copper.

Preferably, the detection area in the detection chip is embedded with a silicon wafer attached with a nano metal material, and the nano metal material is used for enhancing Raman spectroscopy.

As a further preferred technical solution of the present invention, the size of the silicon wafer is preferably 5mm*5mm.

Preferably, after the filter chip is separated from the detection chip, it is injected into distilled water for washing 3-5 times, dried at 60°C, and then packaged with a sealing film after drying, and the packaged detection chip can be reused.

Preferably, the quality components include caffeine and L-theanine.

Preferably, the nano-metal material is one or more of flower-shaped nano-silver material or GO/Ag composite nano-material.

Preferably, the material of the detection chip is PMMA.

Preferably, the portable Raman spectrum detection device includes a mechanical adjustment device, a hand-held Raman detector, a detection end, and a data transmission end.

Preferably, the mechanical adjustment device includes a motor, an output end of the motor is connected to a hand-held Raman detector, and the motor is used to control the hand-held Raman detector to move horizontally to different detection cells of the detection chip Perform multi-point detection.

Preferably, the hand-held Raman detector is equipped with an on-board laser, a USB laser, a serial port laser and a hand-held laser, with a maximum power of 500mW and a maximum integration time of 65535ms.

Preferably, a fixing device is connected to the detection end, the fixing device is used to fix the detection chip, and the detection end is located 3.5 mm below the hand-held Raman detector.

Preferably, the data transmission end is connected to the hand-held Raman detector through a USB cable, and the collected data can be processed and converted into the specific content of each quality component.

Preferably, a rectangular opening is opened on the outer wall of the hand-held Raman detector on three sides of the closed outer wall, and a sealing plate is clamped to the inner wall of the rectangular opening, and the sealing plate is opened when the detection chip is put into the detection end, Turn off when testing, so that testing is in a dark room environment.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention proposes for the first time that the microfluidic chip is combined with the SERS detection technology for the rapid identification of the quality components of tea trees in the field, which greatly improves the detection efficiency.

2. The present invention uses PMMA material as the detection chip. The material itself is cheap, which greatly reduces the cost. At the same time, the chip has the advantages of high throughput, less sampling, and fast detection.

3. Due to the reusability of foamed copper, the filter chip used in the present invention can be recycled and reused by washing with distilled water, which greatly reduces the cost.

4. The present invention realizes the automatic pretreatment and filtration of tea leaves through the combination of the filter chip and the detection chip, and this combination enables the tea samples to be filtered without external force, making the operation simpler and faster.

5. The substrates used in the present invention are all adapted to different quality components of the tea tree to achieve the highest spectral intensity so as to make the detection results more accurate, such as the flower-shaped nano-silver used for the detection of caffeine and the GO used for the detection of L-theanine. /Ag composite nanomaterials, achieving highly sensitive response for low-content component detection.

6. The detection chip in the present invention can simultaneously receive multiple groups of processed tea samples and detect various tea quality components, with high detection efficiency and suitable for rapid and batch detection in the field.

7. The detection data obtained by the present invention does not need an external computer, and the data transmission terminal can directly send the detection results to the cloud, and can be viewed in the mobile phone, which greatly enhances the convenience of detection.

8. The Raman spectroscopic method for determining the quality components of tea trees provided by the present invention is suitable for field operations, and the rapid determination of the quality components is beneficial to the rapid directional breeding of specific tea varieties in the field, and has potential application value.

Description of drawings

Fig. 1 is the average Raman spectrum of the caffeine solution that the embodiment of the present invention 2 detects gained different concentration gradients, and the concentration of caffeine solution in the figure is: a, ^10-4 ; b, ^10-5 ; c, ^10-6 ; d, 10 ^-7 ; e, 10 ^-8 ; f, 10 ^-9 ;

Fig. 2 is the average Raman spectrum of the L-theanine solution of the embodiment of the present invention 3 detection gained different concentration gradients, and the concentration of L-theanine solution in the figure is: a, ^10-4 ; b, ^10-5 ; c, ^10-6 ; d, ^10-7 ; e, ^10-8 ; f, ^10-9 ;

Fig. 3 is the design schematic diagram of the filter chip in the embodiment 1 of the present invention;

Fig. 4 is the design schematic diagram of the detection chip in the embodiment 1 of the present invention;

Fig. 5 is the flow chart that the patent of the present invention detects tea quality components;

FIG. 6 is a schematic diagram of the Raman spectrum detection device of the present invention.

Among them, in the figure: 1. Liquid inlet; 2. Exhaust hole; 3. Liquid storage tank; 4. Filtration part; 5. Sealing film; 6. Fitting column; 7. Fitting hole; Pool; 9. Detection area; 10. Hand-held Raman detector; 11. Detection end; 12. Data transmission end.

Detailed ways

In order to make the invention purpose, technical solutions and invention advantages of the present invention more clearly described, the present invention will be further explained in detail below with reference to the accompanying drawings.

It should be noted that, unless otherwise specified, the reagents or substances involved in the present invention, such as copper foam, are purchased through commercial channels.

Example 1

A device for detecting the quality components of tea samples is composed of a portable Raman spectrum detection device, a filter chip and a detection chip, wherein the portable Raman spectrum detection device detects the tea samples in the detection chip.

Referring to FIG. 3 , in this embodiment, the filter chip includes a base, and the base is provided with a liquid inlet 1, a liquid storage tank 3, a filter part 4, and a sealing film 5 in sequence from top to bottom; wherein, the liquid inlet 1. The vertical base is arranged, the side wall of the liquid inlet 1 is provided with a channel that communicates with the liquid storage tank 3, the upper part of the liquid storage tank 3 is provided with an exhaust hole 2, and the lower part of the liquid storage tank 3 is connected with a In the filter part 4, the end of the filter part 4 away from the liquid storage tank 3 is provided with an outlet channel, the bottom of the outlet channel is provided with the sealing film 5, and the bottom of the base close to one end of the outlet channel is provided with 2. A fitting column 6. Among them, the exhaust hole is used to connect with the outside atmosphere; the outlet of the liquid storage tank is sealed with a sealing film before the filter chip and the detection chip are not connected to prevent the liquid to be tested from flowing out during sample addition.

In this embodiment, there are no special requirements for the materials of the base, the liquid inlet 1, the liquid storage tank 3, the filter part 4, and the sealing film 5, which can be stainless steel or common materials such as glass; for the liquid inlet 1, The installation form inside the liquid storage tank 3 , the filter part 4 , the sealing film 5 and the connection form of the above components and the base are also not specifically limited in this embodiment, as long as the normal connection is satisfied.

Further referring to FIG. 4 , the detection chip includes a fitting hole 7 , a filtrate storage tank 8 and a detection area 9 , and the number of the fitting hole 7 is 2, which are correspondingly fitted with the two fitting columns 6 in the filter chip, It is used to fix the filter chip when the filter chip is vertically connected with the detection chip; the filtrate storage tank 8 is used to store excess filtrate. When the filter chip is combined with the detection chip, the sealing film is torn off, and under the action of gravity, the liquid to be tested enters the filtrate storage tank of the detection chip through the filter part, and contacts the silicon wafer in the detection area.

In this embodiment, the detection area is inlaid with a silicon wafer, and a nano metal material is attached to the silicon wafer for enhancing Raman spectroscopy.

As a preferred implementation in this embodiment, the size of the silicon wafer is 5mm*5mm.

In this embodiment, a filter material is installed in the filter part, which is used for filtering the tea samples.

As a preferred implementation in this embodiment, the filter material is preferably foamed copper.

As a further improvement to this embodiment, the material of the detection chip is PMMA.

Referring to FIG. 6 , the portable Raman spectrum detection device includes a mechanical adjustment device (not shown in the figure), a hand-held Raman detector 10 , a detection end 11 , and a data transmission end 12 .

In this embodiment, the mechanical adjustment device includes a motor, the output end of the motor is connected to the hand-held Raman detector, and the motor is used to control the horizontal movement of the hand-held Raman detector to change the detection chip. The detection cell performs multi-point detection.

In this embodiment, the handheld Raman detector is equipped with an onboard laser, a USB laser, a serial port laser, and a handheld laser.

In this embodiment, a fixing device is connected to the detection end, the fixing device is used to fix the detection chip, and the detection end is located 3.5 mm below the hand-held Raman detector.

In this embodiment, the data transmission end is connected to the hand-held Raman detector through a USB cable, and the collected data can be processed and converted into the specific content of each quality component.

In this embodiment, a rectangular opening is opened on the outer wall of the three sides of the hand-held Raman detector, which is sealed on one side, and a sealing plate (not shown in the figure) is clamped to the inner wall of the rectangular opening. When the chip is put into the detection end, it is turned on, and it is closed when the detection is performed, so that the detection is in a dark room environment.

In this embodiment, the mentioned mechanical adjustment device, the fixing device on the detection end, the sealing plate and the on-board laser, USB laser, serial port laser and hand-held laser are all in the prior art. Therefore, the present invention does not specifically limit the specific structure or model.

Continue to refer to Fig. 5, utilize the above-mentioned portable Raman spectrum detection device, filter chip and detection chip to cooperate to detect the quality components of tea samples, including the following steps:

S1, add distilled water after the tea leaves collected are pulverized to obtain tea samples;

S2, take the tea samples obtained in step S1, and inject them into the filter chip through the liquid inlet;

S3, connecting the filter chip in step S2 with the detection chip;

S4, tear off the sealing film at the outlet channel of the filter chip, and the tea sample flows into the detection area of the detection chip through the filter material;

S5. After the filtration, separate the filter chip from the detection chip, and at the same time treat the filter chip for reuse;

S6, put the detection chip into the portable Raman spectrum detection device for sample detection;

S7, the detection result is processed to obtain the component content.

In this embodiment, the wavelength of the laser used for detection by the portable Raman spectrum detection device is 500-800 nm, the laser power range is 50-200 mW, and the signal collection time range is 1-20 s.

In this embodiment, the filter chip and the detection chip are separated and then injected into distilled water for washing 3-5 times, dried at 60°C, and packaged with a sealing film after drying. The packaged detection chip can be reused, and repeated use can be extremely Greatly reduce costs.

Example 2

This example provides a device described in Example 1 for the rapid determination of caffeine content in tea trees in the field, wherein the nano-metal material uses flower-shaped silver nano-materials.

In this embodiment, the preparation method of flower-like silver nanomaterials is as follows: add 10 mL of deionized water, 2 mL of PVP (polyvinylpyrrolidone) solution (1%) and 0.2 mL of AgNO ₃ solution (1 mol/L) into a clean beaker, and mix The solution was stirred on a constant temperature magnetic stirrer at room temperature, and after stirring evenly, 1 ml of ascorbic acid solution (0.1 mol/L) was quickly added to the mixed solution and stirred for 15 min. Finally, the reaction product was centrifuged by a high-speed centrifuge for 10 min (5000 r/min) to separate from the solvent, and redispersed in 10 mL of deionized water by ultrasonic vibration. Repeat the centrifugation-dispersion step 3 times to remove impurities.

Referring to Fig. 5, the specific method of the determination is as follows: use a pipette to inject 1-2 ml of caffeine solutions with different concentration gradients into the filter chip, fit the filter chip and the caffeine detection chip, tear off the sealing film and filter, after filtering Separate the filter chip and the caffeine detection chip, put the caffeine detection chip into the detection end of the Raman spectrum detection device, start the hand-held Raman detector to perform Raman spectrum detection, the laser wavelength used for detection is 500-800nm, and the laser power is 500-800nm. For each concentration gradient, 8 to 12 different sites will be randomly selected for detection and the data will be transmitted to the cloud to calculate the average Raman spectrum.

The detected average Raman spectra of caffeine solutions with different concentration gradients are shown in Figure 1.

Example 3

This example provides a device described in Example 1 for the rapid determination of L-theanine content in tea trees in the field, wherein the nano-metal material uses GO/Ag composite nano-materials.

In this example, the preparation method of the GO/Ag composite nanomaterial is as follows: 20 mL of GO dispersion (1 mg/mL) and 4 mL of AgNO ₃ solution (0.2 mol/L) are sequentially added to a beaker. After magnetic stirring for 3 hours, 2 mL of ascorbic acid solution (0.5 mol/L) was quickly added to the beaker and stirring was continued for 1 hour. After stirring, the reaction product was separated from the solvent by centrifugation and washed several times with deionized water.

In this example, the preparation method of the GO dispersion is as follows: weigh 0.8g of graphite powder and add it to a beaker with a capacity of 250mL, slowly add 50mL of concentrated sulfuric acid to the beaker, then slowly add 4g of potassium permanganate, and then add 4g of potassium permanganate to the beaker. Place on a magnetic stirrer and stir (1500r/min) for 4h. After stirring, 4 mL of H ₂ O ₂ solution (30%) and 100 mL of deionized water were slowly added to the beaker in sequence, and then the beaker was placed in an ultrasonic shaker for ultrasonic vibration for 30 minutes. After the ultrasonic vibration is completed, the solution in the beaker is placed in a centrifuge for centrifugation, and the centrifuged solid products are washed with deionized water and dilute hydrochloric acid respectively. Repeat the centrifugation-washing step several times. Finally, the obtained GO was dispersed in 20 mL of deionized water by ultrasonic vibration to obtain a GO dispersion.

Referring to Fig. 5, the specific method for the determination is: inject 1-2 ml of L-theanine solutions with different concentration gradients into the filter chip with a pipette, and then tear off the filter chip and the L-theanine detection chip after fitting. The sealing film is filtered. After filtering, the filter chip and the L-theanine detection chip are separated. The L-theanine detection chip is put into the detection end of the Raman spectrum detection device, and the hand-held Raman detector is started for pulling. Mann spectrum detection, the laser wavelength used for detection is 500-800nm, the laser power is 50-150mW, the signal acquisition time is 1-6s, and each concentration gradient will randomly select 8-12 different sites for detection and transmit the data to The cloud calculates the average Raman spectrum.

The detected average Raman spectra of L-theanine solutions with different concentration gradients are shown in Figure 2.

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (3)

1. a method for rapidly measuring tea tree quality composition in the field based on Raman detection, is characterized in that, use portable Raman spectrum detection device, filter chip and detection chip to cooperate to detect the quality composition of tea sample; Wherein, the method includes the following steps: S1, add distilled water after the tea leaves collected are pulverized to obtain tea samples; S2, take the tea samples obtained in step S1, and inject them into the filter chip through the liquid inlet; S3, connecting the filter chip in step S2 with the detection chip; S4, tear off the sealing film at the outlet channel of the filter chip, and the tea sample flows into the detection area of the detection chip through the filter material; S5. After the filtration, separate the filter chip from the detection chip, and at the same time treat the filter chip for reuse; S6, put the detection chip into the portable Raman spectrum detection device for sample detection; S7, the detection result is processed, namely obtains the component content; Wherein, the filter chip includes a base, and the base is provided with a liquid inlet, a liquid storage tank, a filter part, and a sealing film in sequence from top to bottom; wherein, the liquid inlet is arranged perpendicular to the base, and the liquid inlet side The wall is provided with a channel communicating with the liquid storage tank, the upper part of the liquid storage tank is provided with an exhaust hole, the lower part of the liquid storage tank is connected with the filter part, and the end of the filter part away from the liquid storage tank is provided with an outlet channel, the sealing film is arranged at the lowermost part of the outlet channel, and the bottom of the base close to one end of the outlet channel is arranged with not less than 2 fitting posts; The detection chip includes a fitting hole, a filtrate storage tank and a detection area. The fitting hole is fitted with the fitting column and the number of the two is the same, which is used for the filter chip when the filter chip and the detection chip are vertically connected. Fixed; the filtrate storage tank is used to store excess filtrate; Among them, the filter part is equipped with filter material, which is used for the filtration of tea samples; Wherein, the filter material is copper foam; Wherein, the quality components include caffeine and L-theanine; Wherein, the detection area in the detection chip is embedded with a silicon wafer attached with nano metal material; the size of the silicon wafer is 5mm*5mm; Wherein, the nano metal material is one or more of flower-shaped nano silver material or GO/Ag composite nano material; Among them, flower-shaped nano-silver material was used to detect caffeine, and GO/Ag composite nano-material was used to detect L-theanine. 2 . The method for rapidly measuring the quality components of tea trees in the field based on Raman detection according to claim 1 , wherein the wavelength of the laser used in the detection of the portable Raman spectrum detection device is 500-800 nm, and the laser power is 50-200 mW , the signal acquisition time is 1 ~ 20s. 3. a kind of method for rapidly measuring tea tree quality components based on Raman detection according to any one of claims 1-2, it is characterized in that, after filter chip and detection chip are separated, inject distilled water to wash 3～5 times, It is dried at 60°C, and then packaged with a sealing film. The packaged detection chip can be reused.

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