CN105784570B - Particle online detection device and detection method based on microfluidic chip - Google Patents

Abstract

The invention discloses a particle online detection device based on a microfluidic chip and a detection method thereof, wherein the device comprises the microfluidic chip, a first impedance analyzer and a second impedance analyzer; the microfluidic chip comprises a substrate part and a chip main body arranged on the substrate part; the chip main body includes: the first liquid inlet hole, the second liquid inlet hole, the first liquid outlet hole and the second liquid outlet hole are arranged on the substrate component; the particle separation region is used for separating ferromagnetic particles and non-ferromagnetic particles in the oil liquid under the action of a magnetic field; a magnetic member mounting region disposed on the substrate member and located at one side of the first microchannel; a magnetic member disposed on the magnetic member mounting region for providing a magnetic field; a particle detection region; the invention can realize the distinguishing and on-line continuous counting of ferromagnetic particles and non-ferromagnetic particles in oil, and is suitable for on-line detection and analysis of oil, in particular to the detection and analysis of oil on sailing ships.

Description

Particle online detection device and detection method based on microfluidic chip

technical field

The invention belongs to the technical field of oil detection, and specifically relates to a microfluidic chip-based particle on-line detection device and a detection method thereof.

Background technique

Oil monitoring technology is a way to obtain the lubrication information and wear status of the machine by analyzing the performance changes of the lubricant being used and the wear particles carried by the monitored machine, as well as to evaluate the machine condition and predict the failure, and determine The cause of the failure, the type of failure and the technology of the failed part. Machine status detection based on oil monitoring technology is one of the essential methods in modern industrial maintenance activities, and has considerable economic benefits. The detection technology for metal abrasive particles in oil has become the main content of oil monitoring technology.

According to the different working principles of the sensors selected in the oil on-line detection system, the oil on-line detection technologies in the prior art can be divided into the following categories:

1. Physical and chemical analysis technology: refers to the technology that uses instruments to detect and analyze the physical and chemical indicators of oil samples such as viscosity, flash point, moisture, acid value and metal abrasive particles in the laboratory. The physical and chemical analysis technology has high detection accuracy, can detect various performance indicators of lubricating oil, make a comprehensive analysis, and effectively extend the replacement period of lubricating oil. Commonly used oil physical and chemical analysis instruments include viscometers, titrators and infrared spectrometers. However, the physical and chemical analysis technology also has the defects of long detection time, high cost, complicated operation process, can only be used for laboratory measurement, and is not suitable for rapid online detection of oil.

2. Ferrography technology: It is an oil detection technology that uses magnetic gradient and gravity gradient to separate metal abrasive particles from lubricating oil and arrange them according to size. Ferrography can determine the size and nature of wear particles in oil. Commonly used ferrography instruments are online ferrography. However, ferrography technology has the disadvantages of inaccuracy in quantitative ferrography, wear particle analysis mainly depends on the knowledge level and practical experience of the operator, sampling is not representative, it takes a long time to make ferrography, and the analysis speed is not high.

3. Spectral analysis technology: including atomic emission spectrometry, atomic absorption spectrometry, infrared spectroscopic analysis and ray fluorescence spectrometry. Spectral analysis technology has a strong ability to identify particles and a high degree of equipment integration. However, spectroscopic analysis technology has the disadvantages that spectroscopic instruments are generally expensive, installation conditions are strict, and experimental costs are high.

4. Electrical monitoring technology: The commonly used technology is resistive online monitoring technology, which mainly uses different resistivity of different abrasive particles. When oil passes through the resistance sensor, different resistance values reflect the concentration and particle size distribution of abrasive particles. However, the resistive online monitoring technology has the disadvantage of low sensitivity and cannot detect tiny particles.

It can be seen from the above that the online oil detection technology in the prior art has certain limitations, and cannot be well adapted to the requirements of high sensitivity and online oil detection.

Contents of the invention

In view of the above problems, the present invention develops a microfluidic chip-based particle on-line detection device and a detection method thereof.

Technical means of the present invention is as follows:

A particle on-line detection device based on a microfluidic chip, comprising a microfluidic chip, a first impedance analyzer, and a second impedance analyzer; the microfluidic chip includes a substrate component and a chip body disposed on the substrate component; The chip body includes:

a first liquid inlet hole, a second liquid inlet hole, a first liquid outlet hole and a second liquid outlet hole arranged on the substrate component;

A particle separation area for separating ferromagnetic particles and non-ferromagnetic particles in the oil under the action of a magnetic field; the particle separation area includes first microchannels and second microchannels distributed on the substrate part; The oil liquid containing particles enters the first microchannel through the first liquid inlet hole; the oil liquid containing particles enters the second microchannel through the second liquid inlet hole; a first opening is opened in the middle of the first microchannel, and the first microchannel The middle part of the second microchannel is provided with a second opening that communicates with the first opening; the ferromagnetic particles obtained after the separation process enter the particle detection area through the first microchannel, and the non-ferromagnetic particles obtained after the separation process pass through the second microchannel. The second microchannel enters the particle detection area;

A magnetic component placement area disposed on the substrate component and located on one side of the first microchannel;

A magnetic component placed on the magnetic component placement area for providing a magnetic field;

Particle detection area; the particle detection area includes a third microchannel, a fourth microchannel, a first detection electrode and a second detection electrode arranged on the substrate part and respectively located on both sides of the third microchannel, and a second detection electrode arranged on the substrate part The third detection electrode and the fourth detection electrode on both sides of the fourth microchannel; the beginning of the third microchannel communicates with the end of the first microchannel, and the end of the third microchannel communicates with the first liquid outlet connected; the beginning of the fourth microchannel communicates with the second microchannel, and the end of the fourth microchannel communicates with the second liquid outlet;

When the third microchannel passes through ferromagnetic particles, the capacitance value between the first detection electrode and the second detection electrode changes; the first impedance analyzer and the first detection electrode, the second detection electrode The electrodes are connected to obtain the change of the capacitance value between the first detection electrode and the second detection electrode; according to the change of the capacitance value between the first detection electrode and the second detection electrode, the temperature of the ferromagnetic particles passing through the third microchannel is obtained. quantity;

When the fourth microchannel passes through non-ferromagnetic particles, the capacitance value between the third detection electrode and the fourth detection electrode changes; the second impedance analyzer and the third detection electrode, the fourth detection electrode The detection electrodes are connected to obtain the change of the capacitance value between the third detection electrode and the fourth detection electrode; according to the change of the capacitance value between the third detection electrode and the fourth detection electrode, the non-ferromagnetic the number of particles;

In addition, the particle separation area also includes:

A first partition member and a second partition member arranged between the first microchannel and the second microchannel; one end of the first partition is located at the beginning of the particle separation region, and the other end has a slope; the One end of the second partition member is located at the end of the particle separation area, and the other end has an inclined surface; the inclined direction of the inclined surface of the first partition member is symmetrical to the inclined direction of the inclined surface of the second partition member; Through the setting of the first partition member and the second partition member, the first opening of the first microchannel is larger than the second opening of the second microchannel;

In addition, the device also includes a display device connected to the first impedance analyzer and the second impedance analyzer, and the display device is used to display the known quantity of ferromagnetic particles and non-ferromagnetic particles;

Further, the inclination angle of the slope of the first partition member and the slope of the slope of the second partition member are both 45 degrees;

Further, the substrate part is made of PMMA material; the chip body is made of PDMS material;

Further, according to the capacitance value change situation between the first detection electrode and the second detection electrode, the particle size state of the ferromagnetic particles passing through the third microchannel is known; according to the capacitance value between the third detection electrode and the fourth detection electrode The state of the particle size of the non-ferromagnetic particles passing through the fourth microchannel can be obtained from the changes.

An on-line particle detection method based on a microfluidic chip, the detection method is realized by the above-mentioned particle on-line detection device based on a microfluidic chip, and includes the following steps:

Step 1: Transport the oil without particles to the first microchannel through the first liquid inlet hole, and transport the oil containing particles to the second microchannel through the second liquid inlet;

Step 2: Under the action of the magnetic field, the ferromagnetic particles entering the particle separation area enter the first microchannel from the second microchannel through the area where the first microchannel communicates with the second microchannel, and move along the first microchannel Transported to the third microchannel, the non-ferromagnetic particles entering the particle separation region continue to flow along the second microchannel and enter the fourth microchannel;

Step 3: When the third microchannel passes through the ferromagnetic particles, the first impedance analyzer obtains the change of the capacitance value between the first detection electrode and the second detection electrode; according to the first detection electrode, the second detection electrode The amount of the ferromagnetic particles passing through the third microchannel is obtained by the change of the capacitance value between the electrodes; when the fourth microchannel passes through the non-ferromagnetic particles, the second impedance analyzer obtains the third detection electrode, the fourth Detecting changes in the capacitance value between the electrodes; knowing the quantity of non-ferromagnetic particles passing through the fourth microchannel according to the changes in the capacitance value between the third detection electrode and the fourth detection electrode;

In addition, the detection method also includes the following steps:

According to the change of the capacitance value between the first detection electrode and the second detection electrode, the particle size state of the ferromagnetic particles passing through the third microchannel is known; according to the change of the capacitance value between the third detection electrode and the fourth detection electrode, it is known Particle size state of non-ferromagnetic particles passing through the fourth microchannel.

Due to the adoption of the above technical solution, the microfluidic chip-based particle on-line detection device and its detection method provided by the present invention can realize the distinction between ferromagnetic particles and non-ferromagnetic particles in oil based on the principle of capacitance detection in electrical monitoring technology And online continuous counting, suitable for online detection and analysis of oil, especially for oil detection and analysis on sailing ships.

Description of drawings

Fig. 1 is the structural representation of device described in the present invention;

Fig. 2 is a schematic structural view of the chip main body and substrate components of the present invention;

Fig. 3 is a flowchart of the method of the present invention;

In the figure: 1. Substrate component, 2. Chip body, 3. First liquid inlet hole, 4. Second liquid inlet hole, 5. First liquid outlet hole, 6. Second liquid outlet hole, 7. Particle separation area , 8, the magnetic component placement area, 10, the magnetic component, 71, the first microchannel, 72, the second microchannel, 73, the first opening, 74, the second opening, 75, the first separation component, 76, the second Separator, 77, slope, 91, third microchannel, 92, fourth microchannel, 93, first detection electrode, 94, second detection electrode, 95, third detection electrode, 96, fourth detection electrode.

Detailed ways

As shown in Figure 1 and Figure 2, a particle on-line detection device based on a microfluidic chip includes a microfluidic chip, a first impedance analyzer and a second impedance analyzer; the microfluidic chip includes a substrate part 1 And the chip main body 2 arranged on the substrate part 1; the chip main body 2 includes: the first liquid inlet hole 3, the second liquid inlet hole 4, the first liquid outlet hole 5 and the second liquid outlet hole arranged on the substrate part 1 Liquid hole 6; particle separation area 7 for separating ferromagnetic particles and non-ferromagnetic particles in the oil under the action of a magnetic field; said particle separation area 7 includes first microchannels distributed on the substrate part 1 71 and the second microchannel 72; the oil that does not contain particles enters the first microchannel 71 through the first liquid inlet 3; the oil containing particles enters the second microchannel 72 through the second liquid inlet 4; the first A first opening 73 is provided in the middle part of a microchannel 71, and a second opening 74 communicating with the first opening 73 is provided in the middle part of the second microchannel 72; the ferromagnetic particles obtained after the separation process pass through the first microchannel The channel 71 enters the particle detection area, and the non-ferromagnetic particles obtained after the separation process enter the particle detection area through the second microchannel 72; the magnetic component placement area arranged on the substrate component 1 and on the side of the first microchannel 71 8; Placed on the magnetic component placement area 8, the magnetic component 10 for providing a magnetic field; the particle detection area; the particle detection area includes a third microchannel 91, a fourth microchannel 92, and is arranged on the substrate component 1 And the first detection electrode 93 and the second detection electrode 94 respectively located on both sides of the third microchannel 91, and the third detection electrode 95 and the fourth detection electrode 95 and the fourth detection electrode which are arranged on the substrate member 1 and respectively located on both sides of the fourth microchannel 92 Electrode 96; The beginning of the third microchannel 91 is connected with the end of the first microchannel 71, and the end of the third microchannel 91 is connected with the first outlet hole 5; The beginning of the fourth microchannel 92 is connected with the second end of the microchannel. The microchannel 72 is connected, and the end of the fourth microchannel 92 is connected with the second liquid outlet hole 6; when the third microchannel 91 passes through the ferromagnetic particle, the first detection electrode 93, the second detection electrode The capacitance value between 94 changes; the first impedance analyzer is connected with the first detection electrode 93 and the second detection electrode 94 to obtain the capacitance value between the first detection electrode 93 and the second detection electrode 94 Change situation; According to the capacitance value change situation between the first detection electrode 93 and the second detection electrode 94, the quantity of ferromagnetic particles passing through the third microchannel 91 is known; when the fourth microchannel 92 passes through non-ferromagnetic particles , the capacitance value between the third detection electrode 95 and the fourth detection electrode 96 changes; the second impedance analyzer is connected to the third detection electrode 95 and the fourth detection electrode 96 to obtain the third detection The capacitance value change situation between electrode 95, the 4th detection electrode 96; According to the capacitance value change situation between the 3rd detection electrode 95, the 4th detection electrode 96, know the quantity of the non-ferromagnetic particles through the 4th microchannel 92; In addition, the particle separation area 7 also includes: The first partition member 75 and the second partition member 76 between the first microchannel 71 and the second microchannel 72; one end of the first partition member 75 is positioned at the beginning of the particle separation region 7, and the other end has Inclined surface 77; one end of the second partition member 76 is located at the end of the particle separation area 7, and the other end has an inclined surface 77; the inclined direction of the inclined surface 77 that the first partition member 75 has is the same as that of the second partition The inclination direction of the inclined plane 77 that part 76 has is symmetrical to each other; By the setting of first partition part 75 and second partition part 76, the first opening 73 of the first microchannel 71 is larger than the second opening of the second microchannel 72 74; In addition, the device also includes a display device connected to the first impedance analyzer and the second impedance analyzer, and the display device is used to display the number of known ferromagnetic particles and non-ferromagnetic particles; Further, the inclination angle of the inclined surface 77 of the first partition member 75 and the inclination angle of the inclined surface 77 of the second partition member 76 are both 45 degrees; further, the substrate member 1 is made of PMMA material The chip main body 2 is made of PDMS material; further, according to the change of the capacitance value between the first detection electrode 93 and the second detection electrode 94, the particle size state of the ferromagnetic particles passing through the third microchannel 91 is known; The particle size state of the non-ferromagnetic particles passing through the fourth microchannel 92 can be obtained according to the capacitance value change between the third detection electrode 95 and the fourth detection electrode 96 .

As shown in Figure 3, a particle on-line detection method based on a microfluidic chip, the detection method is implemented using the above-mentioned particle on-line detection device based on a microfluidic chip, and includes the following steps:

Step 1: Transport the oil without particles to the first microchannel 71 through the first liquid inlet 3, and transport the oil containing particles to the second microchannel 72 through the second liquid inlet 4;

Step 2: The ferromagnetic particles entering the particle separation region 7 enter the first microchannel 71 by the second microchannel 72 through the area where the first microchannel 71 communicates with the second microchannel 72 under the action of a magnetic field, and Transported to the third microchannel 91 along the first microchannel 71, the non-ferromagnetic particles entering the particle separation region 7 continue to flow along the second microchannel 72 and enter the fourth microchannel 92;

Step 3: When the third microchannel 91 passes through the ferromagnetic particles, the first impedance analyzer obtains the change of the capacitance value between the first detection electrode 93 and the second detection electrode 94; according to the first detection electrode 93 1. The capacitance value change situation between the second detection electrodes 94 obtains the quantity of the ferromagnetic particles passing through the third microchannel 91; when the fourth microchannel 92 passes through the non-ferromagnetic particles, the second impedance analyzer obtains The capacitance value variation situation between the 3rd detection electrode 95, the 4th detection electrode 96; According to the capacitance value variation situation between the 3rd detection electrode 95, the 4th detection electrode 96, know the non-ferromagnetic particles through the 4th microchannel 92 quantity;

In addition, the detection method also includes the following steps:

According to the capacitance value change situation between the first detection electrode 93, the second detection electrode 94, the particle size state of the ferromagnetic particles passing through the third microchannel 91 is obtained; according to the capacitance between the third detection electrode 95 and the fourth detection electrode 96 The state of the particle size of the non-ferromagnetic particles passing through the fourth microchannel 92 can be obtained from the change of the capacitance value.

In the present invention, the first detection electrode 93 and the second detection electrode 94 are respectively located on both sides of the third microchannel 91. When the third microchannel 91 does not pass through ferromagnetic particles, The capacitance value is a certain reference capacitance value. The capacitance between the first detection electrode 93 and the second detection electrode 94 corresponding to ferromagnetic particles of different sizes is different. After ferromagnetic particles of different sizes pass through the third microchannel 91, Correspondingly, the capacitance between the first detection electrode 93 and the second detection electrode 94 changes, and the first impedance analyzer can generate a corresponding pulse signal, the amplitude of the pulse signal generated by the first impedance analyzer corresponds to the capacitance change value, where the capacitance change value refers to the first detection electrode 93, the second detection electrode 93, the second microchannel 91 when the third microchannel 91 passes through the ferromagnetic particles. The capacitance value between the detection electrodes 94, the difference of the capacitance value between the first detection electrode 93 and the second detection electrode 94 when the third microchannel 91 does not pass through the ferromagnetic particles; The number of ferromagnetic particles passing through the third microchannel 91 can be obtained by making statistics on the pulse signal, and then the number of ferromagnetic particles can be displayed intuitively by using the display device; the change value of capacitance can also reflect the ferromagnetic particles The particle size state can be obtained according to the amplitude of the pulse signal generated by the first impedance analyzer. The higher the amplitude of the pulse signal, the larger the particle size of the ferromagnetic particles, and the lower the amplitude of the pulse signal, then It shows that the smaller the particle size of the ferromagnetic particles, that is, there is a linear correspondence between the amplitude of the pulse signal and the particle size of the ferromagnetic particles.

In the present invention, the third detection electrode 95 and the fourth detection electrode 96 are respectively located on both sides of the fourth microchannel 92. The capacitance value is a certain reference capacitance value, the capacitance between the third detection electrode 95 and the fourth detection electrode 96 corresponding to the non-ferromagnetic particles of different sizes is different, and the non-ferromagnetic particles of different sizes pass through the fourth microchannel After 92, correspondingly, the capacitance between the third detection electrode 95 and the fourth detection electrode 96 changes, and the second impedance analyzer can change according to the capacitance value between the third detection electrode 95 and the fourth detection electrode 96 A corresponding pulse signal is generated, and the amplitude of the pulse signal generated by the second impedance analyzer corresponds to the capacitance change value, where the capacitance change value refers to the third detection electrode when the fourth microchannel 92 passes through the non-ferromagnetic particle 95, the capacitance value between the fourth detection electrodes 96, the difference between the capacitance value between the third detection electrode 95 and the fourth detection electrode 96 when the fourth microchannel 92 does not pass through the non-ferromagnetic particles; The pulse signal generated by the two impedance analyzers is counted, and the number of non-ferromagnetic particles passing through the fourth microchannel 92 can be known, and then the number of non-ferromagnetic particles can be intuitively displayed by the display device; the size of the capacitance change value It can also reflect the particle size state of non-ferromagnetic particles, which can be obtained according to the amplitude of the pulse signal generated by the second impedance analyzer. The higher the amplitude of the pulse signal, the larger the particle size of the non-ferromagnetic particles. The lower the amplitude of the pulse signal, the smaller the particle size of the non-ferromagnetic particles, that is, there is a linear correspondence between the amplitude of the pulse signal and the particle size of the non-ferromagnetic particles.

The specific capacitance detection principles of the first detection electrode 93 and the second detection electrode 94, and the third detection electrode 95 and the fourth detection electrode 96 of the present invention are similar to parallel plate capacitors. We know that the capacitance calculation formula of parallel plate capacitors is: Among them, ε is the dielectric constant of the medium between the metal plates, S is the area of the metal plates, and d is the distance between the two metal plates. It can be seen that when the dielectric constant ε between the metal plates changes , the corresponding capacitance value C will also change; similarly, when the ferromagnetic particles pass through the third microchannel 91 or the non-ferromagnetic particles pass through the fourth microchannel 92, the oil of the corresponding particle volume will be squeezed out, resulting in the first The dielectric constant between the first detection electrode 93 and the second detection electrode 94 or between the third detection electrode 95 and the fourth detection electrode 96 changes, thereby causing a change in the capacitance value.

Impedance analyzer is currently the instrument commonly used to measure capacitance. It can obtain the corresponding parallel equivalent capacitance value according to the measured impedance value, and then obtain the actual capacitance value. It can also be intuitively read by the Labview programming carried by the impedance analyzer itself. actual capacitance value.

The first detection electrode 93, the second detection electrode 94, the third detection electrode 95 and the fourth detection electrode 96 of the present invention can use copper electrodes; the substrate part 1 is made of PMMA (polymethyl methacrylate) material , that is, plexiglass, the material has excellent transparency, good insulation and mechanical strength, the specific gravity is less than half of ordinary glass, and the anti-fragmentation ability is several times higher than ordinary glass; the chip main body 2 adopts PDMS (polydimethyl Silicone) material, PDMS material and PMMA material have good adhesion and good chemical inertness; in general, PDMS thick film with a thickness of hundreds of microns can not only meet the strength requirements, but also can Produce greater deformation; in addition, the PDMS material has good extensibility; the slope 77 that the first partition member 75 has and the slope 77 that the second partition member 76 has help prevent non-ferromagnetic particles from entering the first microsphere. In the channel 71, the oil without particles enters the first microchannel 71 from the first liquid inlet hole 3 through the microinjection pump, and the oil containing particles enters the second microchannel 72 from the second liquid inlet hole 4 through the microinjection pump The display device adopts a display; the magnetic component 10 adopts a permanent magnet, the shape is relatively regular, and it is easy to cooperate with the chip main body 2; the device of the present invention also includes a first liquid inlet 3 and a second liquid inlet 4 , and the oil delivery area between the particle separation area 7; the oil delivery area includes a microchannel communicating with the first liquid inlet hole 3 and the beginning of the first microchannel 71, and communicating with the second liquid inlet hole 4 and the second The microchannel at the beginning of the microchannel 72; when the oil reaches the particle separation area 7, the ferromagnetic particles in the oil are attracted by the magnetic field and pass through the first microchannel 71 and the second microchannel 72 by the second microchannel 72 The connected area enters the first microchannel 71, and is transported to the third microchannel 91 along the first microchannel 71, and the non-ferromagnetic particles entering the particle separation area 7 continue to flow due to their own inertia and fluid viscosity. Flowing along the second microchannel 72, coupled with the slope design of the first partition member 75 and the second partition member 76, makes the first microchannel 71 have a downward impact on the second microchannel 72, preventing the non-ferromagnetic The particles flow into the first microchannel 71; thus separated ferromagnetic particles and non-ferromagnetic particles enter the third microchannel 91 and the fourth microchannel 92, respectively. When the present invention is used, the microfluidic chip can be placed horizontally.

The invention is based on the capacitance detection principle in the electrical monitoring technology, can realize the distinction and online continuous counting of ferromagnetic particles and non-ferromagnetic particles in oil, and is suitable for online detection and analysis of oil, especially for detection and analysis of oil on sailing ships; The invention can realize the real-time measurement of the metal particles in the oil, can respectively obtain the quantity of the ferromagnetic particles and the non-ferromagnetic particles, is suitable for the online detection of the oil, and completes the more detailed detection and distinction of the particles in the oil.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (8)

1. A particle on-line detection device based on a microfluidic chip, characterized in that the device includes a microfluidic chip, a first impedance analyzer and a second impedance analyzer; the microfluidic chip includes a substrate part and an arrangement A chip body on a substrate part; said chip body comprising: a first liquid inlet hole, a second liquid inlet hole, a first liquid outlet hole and a second liquid outlet hole arranged on the substrate component; A particle separation area for separating ferromagnetic particles and non-ferromagnetic particles in the oil under the action of a magnetic field; the particle separation area includes first microchannels and second microchannels distributed on the substrate part; The oil liquid containing particles enters the first microchannel through the first liquid inlet hole; the oil liquid containing particles enters the second microchannel through the second liquid inlet hole; a first opening is opened in the middle of the first microchannel, and the first microchannel The middle part of the second microchannel is provided with a second opening that communicates with the first opening; the ferromagnetic particles obtained after the separation process enter the particle detection area through the first microchannel, and the non-ferromagnetic particles obtained after the separation process pass through the second microchannel. The second microchannel enters the particle detection area; A magnetic component placement area disposed on the substrate component and located on one side of the first microchannel; A magnetic component placed on the magnetic component placement area for providing a magnetic field; Particle detection area; the particle detection area includes a third microchannel, a fourth microchannel, a first detection electrode and a second detection electrode arranged on the substrate part and respectively located on both sides of the third microchannel, and a second detection electrode arranged on the substrate part The third detection electrode and the fourth detection electrode on both sides of the fourth microchannel; the beginning of the third microchannel communicates with the end of the first microchannel, and the end of the third microchannel communicates with the first liquid outlet connected; the beginning of the fourth microchannel communicates with the second microchannel, and the end of the fourth microchannel communicates with the second liquid outlet; When the third microchannel passes through ferromagnetic particles, the capacitance value between the first detection electrode and the second detection electrode changes; the first impedance analyzer and the first detection electrode, the second detection electrode The electrodes are connected to obtain the change of the capacitance value between the first detection electrode and the second detection electrode; according to the change of the capacitance value between the first detection electrode and the second detection electrode, the temperature of the ferromagnetic particles passing through the third microchannel is obtained. quantity; When the fourth microchannel passes through non-ferromagnetic particles, the capacitance value between the third detection electrode and the fourth detection electrode changes; the second impedance analyzer and the third detection electrode, the fourth detection electrode The detection electrodes are connected to obtain the change of the capacitance value between the third detection electrode and the fourth detection electrode; according to the change of the capacitance value between the third detection electrode and the fourth detection electrode, the non-ferromagnetic the number of particles. 2. The particle on-line detection device based on the microfluidic chip according to claim 1, wherein the particle separation area further comprises: A first partition member and a second partition member arranged between the first microchannel and the second microchannel; one end of the first partition is located at the beginning of the particle separation region, and the other end has a slope; the One end of the second partition member is located at the end of the particle separation area, and the other end has an inclined surface; the inclined direction of the inclined surface of the first partition member is symmetrical to the inclined direction of the inclined surface of the second partition member; Through the arrangement of the first partition member and the second partition member, the first opening of the first microchannel is larger than the second opening of the second microchannel. 3. The particle on-line detection device based on the microfluidic chip according to claim 1, wherein the device also includes a display device connected with the first impedance analyzer and the second impedance analyzer, and the display device uses It is used to display the number of known ferromagnetic particles and the number of non-ferromagnetic particles. 4. The particle on-line detection device based on a microfluidic chip according to claim 2, wherein the inclination angle of the slope that the first partition member has and the slope angle that the second partition member has are both 45 degree. 5. The particle on-line detection device based on a microfluidic chip according to claim 1, characterized in that the substrate part is made of PMMA material; the chip main body is made of PDMS material. 6. The particle on-line detection device based on the microfluidic chip according to claim 1, characterized in that the ferromagnetic particles passing through the third microchannel are known according to the capacitance value variation between the first detection electrode and the second detection electrode. The particle size state of the particle size; the particle size state of the non-ferromagnetic particles passing through the fourth microchannel is obtained according to the capacitance value change between the third detection electrode and the fourth detection electrode. 7. A particle on-line detection method based on a microfluidic chip, characterized in that the detection method is realized by the particle on-line detection device based on a microfluidic chip according to claim 2, and comprises the steps of: Step 1: Transport the oil without particles to the first microchannel through the first liquid inlet hole, and transport the oil containing particles to the second microchannel through the second liquid inlet; Step 2: Under the action of the magnetic field, the ferromagnetic particles entering the particle separation area enter the first microchannel from the second microchannel through the area where the first microchannel communicates with the second microchannel, and move along the first microchannel Transported to the third microchannel, the non-ferromagnetic particles entering the particle separation region continue to flow along the second microchannel and enter the fourth microchannel; Step 3: When the third microchannel passes through the ferromagnetic particles, the first impedance analyzer obtains the change of the capacitance value between the first detection electrode and the second detection electrode; according to the first detection electrode, the second detection electrode The amount of the ferromagnetic particles passing through the third microchannel is obtained by the change of the capacitance value between the electrodes; when the fourth microchannel passes through the non-ferromagnetic particles, the second impedance analyzer obtains the third detection electrode, the fourth Detecting the change of capacitance value between the electrodes; obtaining the quantity of non-ferromagnetic particles passing through the fourth microchannel according to the change of capacitance value between the third detection electrode and the fourth detection electrode. 8. The particle online detection method based on the microfluidic chip according to claim 7, characterized in that the detection method further comprises the steps: According to the change of the capacitance value between the first detection electrode and the second detection electrode, the particle size state of the ferromagnetic particles passing through the third microchannel is known; according to the change of the capacitance value between the third detection electrode and the fourth detection electrode, it is known Particle size state of non-ferromagnetic particles passing through the fourth microchannel.