阅读说明：本技术 一种原位被动监测养殖水体中抗生素含量的方法 (Method for passively monitoring antibiotic content in aquaculture water in situ ) 是由 李娟英 文聚 陈以芹 郑儒懿 盛博维 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种原位被动监测养殖水体中抗生素含量的方法,采用XDA-1树脂作为吸附膜材料、以琼脂糖凝胶作为扩散膜材料,将制得的吸附膜、扩散膜和聚醚砜圆状过滤膜组装成DGT装置,通过该装置实现对养殖水体中抗生素的吸附并监测其浓度。XDA-1树脂材料结构稳定、孔隙度高、比表面积大、吸附容量大,对养殖水体中抗生素吸附效果佳,所需时间短,监测结果准确,弥补了瞬时主动采样法浓度监测的不连续性以及误差较大的不足,适用于现场实际环境温度为15-25℃的养殖水体低浓度抗生素监测,且可大范围推广,解决了养殖水体中抗生素浓度传统监测方法中耗时长、流程复杂和成本高等难题。(The invention discloses a method for passively monitoring the content of antibiotics in a culture water body in situ, which adopts XDA-1 resin as an adsorption membrane material and agarose gel as a diffusion membrane material, assembles the prepared adsorption membrane, diffusion membrane and polyether sulfone circular filter membrane into a DGT device, and realizes the adsorption of the antibiotics in the culture water body and monitors the concentration of the antibiotics by the DGT device. The XDA-1 resin material has a stable structure, high porosity, a large specific surface area, a large adsorption capacity, a good antibiotic adsorption effect on the aquaculture water, short required time and accurate monitoring result, overcomes the defects of discontinuity and large error of concentration monitoring by an instantaneous active sampling method, is suitable for monitoring the low-concentration antibiotic of the aquaculture water with the field actual environment temperature of 15-25 ℃, can be popularized in a large range, and solves the problems of long time consumption, complex flow, high cost and the like in the traditional monitoring method for the concentration of the antibiotic in the aquaculture water.)

1. A DGT device that is arranged in normal position to monitor antibiotic content in aquaculture water passively characterized in that includes: the DGT shell is positioned on two sides of the DGT shell, and the composite die interlayer sequentially comprises an adsorption film, a diffusion film and a filtering film, wherein the adsorption film, the diffusion film and the filtering film are in a wafer shape, the inner diameters of the adsorption film, the diffusion film and the filtering film are the same, and the thickness ratio of the adsorption film to the diffusion film to the filtering film is 0.28:1.6: 1; wherein:

the filter membrane is a polyether sulfone circular filter membrane;

the diffusion membrane is obtained by the following preparation method: mixing agarose and ultrapure water in proportion, heating at a speed of 40 ℃/min to 400 ℃, keeping the temperature until the solution is transparent to obtain a hot agarose solution with the concentration of 1.5 percent, quickly pouring the hot agarose solution into a glass mold, cooling to room temperature, cutting into a plurality of wafers, and storing in a culture dish containing ultrapure water at 4 ℃;

the adsorption film is prepared by the following preparation method: the XDA-1 resin is washed by ultrapure water and methanol, washed by ultrapure water and dried by dust-free paper in sequence, ground and sieved by a 200-mesh sieve, then uniformly mixed with the obtained 1.5% hot agarose solution according to the mass-to-volume ratio of 1:10, quickly poured into a glass mold, cooled to room temperature, cut into a plurality of wafers, and stored in a culture dish filled with ultrapure water at 4 ℃.

2. The DGT device of claim 1, wherein the filtration membrane is a polyethersulfone circular filter having a diameter of 25mm, a thickness of 0.14mm and a pore size of 0.45 um.

3. The DGT apparatus of claim 1, wherein the diffusion membrane has an inner diameter of 25mm, a thickness of 0.8mm and a mass of 0.377-0.383 g.

4. The DGT apparatus of claim 1, wherein the adsorption film has an inner diameter of 25mm, a thickness of 0.5mm and a mass of 0.249-0.251 g.

5. The DGT device of claim 1, wherein the DGT housing is methanol rinsed and soaked in pure water, the pure water being blotted dry with a non-dusting paper in use.

6. A method for passively monitoring antibiotic content in aquaculture water in situ, which is carried out by the DGT device of any one of claims 1-5, and comprises the following steps:

placing a plurality of DGT devices in a plurality of culture water containers with antibiotic concentration of 0.27 ng/mL-0.33 ng/mL and pH value of 7.0-8.5, sealing and packaging the culture water containers with tinfoil, placing the culture water containers in a 25 ℃ constant temperature shaking table with the rotating speed of 120-140 r/min, taking out a certain DGT device in each container for 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h and 6h respectively, and taking out an adsorption film;

(ii) placing the taken adsorption membrane in an elution test tube filled with methanol solution for ultrasonic treatment for 15-20 min, removing the adsorption membrane, and blowing and concentrating elution liquid nitrogen to 50ul (V)_e) Determining the concentration value (C) of the antibiotic in the eluate_e)；

(iii) firstly, calculating the cumulant M on the adsorption film by the formula (1), obtaining a linear relation according to the change of the cumulant M of the antibiotic on the adsorption film along with time, obtaining a slope alpha by linear fitting, and then calculating the diffusion coefficient (D) of the DGT device in the aquaculture water body according to the formula (2), and representing the flux of the antibiotic in the aquaculture water body passing through the diffusion film in unit time; wherein:

elution efficiency of formula (1)In the formula:

ce is the concentration of the antibiotic detected after the concentration of the eluent;

ve is 50 ul;

diffusion coefficient of formula (2)

α is the linear regression slope of the amount of antibiotic (ng) accumulated in the adsorption membrane over time(s);

△ g is the thickness (cm) of the diffusion membrane;

a is the area (cm) of the diffusion film²)；

C is the concentration of the antibiotic in water (ng/mL).

Technical Field

The invention belongs to the technical field of aquaculture water body monitoring, and particularly relates to a method for passively monitoring the content of antibiotics in an aquaculture water body in situ.

Background

When the antibiotics are used for the aquaculture water body, only a small part of the antibiotics can be absorbed and utilized by aquatic organisms, a large amount of residual antibiotics are remained in the aquaculture environment in the form of original forms or metabolites or enter the natural water body environment along with the discharge of aquaculture wastewater, and long-term existing antibiotic residues can induce microorganisms and bacteria to generate drug resistance and bring threats to the health of aquatic plants and even human bodies. At present, most of traditional antibiotic monitoring modes are that instantaneous water samples are actively collected and are subjected to solid-phase extraction and then are measured on a computer, the method is used for actively sampling, the sample concentration is instantaneous, the measurement result cannot reflect the change of the actual concentration of the antibiotic in the aquaculture water body, the measurement process is time-consuming and labor-consuming, the measurement result is discontinuous, and the repeatability is poor.

According to Fick's first diffusion law, the DGT device is placed in the aquaculture water body, and the concentration value of certain ion is obtained by quantitative measurement of certain ion of antibiotic passing through the diffusion membrane with specific thickness in specific time and research and calculation of the buffer dynamic process. At present, DGT is applied to the monitoring of antibiotics in rivers, seawater and sewage plants, the diffusion coefficient D of DGT applied to the actual environment represents the flux of the antibiotics in the environment in unit time through a DGT diffusion membrane, and the diffusion coefficient D in the aquaculture water body is not represented yet.

There are two main techniques for monitoring antibiotics by DGT: (1) one is to use XDA-18 resin as an adsorption film material, but has the defects of small adsorption capacity and the like; (2) another method is an adsorption film made of PCM (material extracted from MOF porous carbon) as a material. Although the adsorption capacity of the adsorption film is large, the adsorption rate is slow, and the adsorption film is used for outdoor actual monitoring for a long time which needs to be placed for about 7 days.

Therefore, the novel technology for sampling and monitoring the antibiotics in the aquaculture water body, which can overcome the defects, is very important, and simultaneously, the characteristic that the DGT is applied to the diffusion coefficient in the aquaculture water body and can also be used for calculating the concentration of the antibiotics in the actual aquaculture water body has important significance.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention discloses a method for passively monitoring the content of antibiotics in a culture water body in situ, which adopts XDA-1 resin as an adsorption membrane material and agarose gel as a diffusion membrane material, assembles the prepared adsorption membrane, diffusion membrane and polyether sulfone circular filter membrane into a DGT device, and realizes the function of monitoring the concentration of antibiotics by adsorbing the antibiotics in the culture water body. The XDA-1 resin material has a stable structure, high porosity, a large specific surface area and a large adsorption capacity, has a good antibiotic adsorption effect in the aquaculture water body, needs short time, has an accurate monitoring result, makes up the defects of discontinuity and large error of concentration monitoring by an instantaneous active sampling method, is suitable for detecting low-concentration antibiotics in the aquaculture water body with the field actual environment temperature of 15-25 ℃, and solves the problems of long time consumption, complex flow, high cost and the like in the traditional monitoring method for the concentration of antibiotics in the aquaculture water body.

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

in a first aspect of the invention, a DGT device for passive in situ monitoring of antibiotic content in an aquaculture water comprises: the DGT shell is positioned on two sides of the DGT shell, and the composite die interlayer sequentially comprises an adsorption film, a diffusion film and a filtering film, wherein the adsorption film, the diffusion film and the filtering film are in a wafer shape, the inner diameters of the adsorption film, the diffusion film and the filtering film are the same, and the thickness ratio of the adsorption film to the diffusion film to the filtering film is 0.28:1.6: 1; wherein:

the filter membrane is a polyether sulfone circular filter membrane;

the diffusion membrane is obtained by the following preparation method: mixing agarose and ultrapure water in proportion, heating at a speed of 40 ℃/min to 400 ℃, keeping the temperature until the solution is transparent to obtain a hot agarose solution with the concentration of 1.5 percent, quickly pouring the hot agarose solution into a glass mold, cooling to room temperature, cutting into a plurality of wafers, and storing in a culture dish containing ultrapure water at 4 ℃;

the adsorption film is prepared by the following preparation method: the XDA-1 resin is washed by ultrapure water and methanol, washed by ultrapure water and dried by dust-free paper in sequence, ground and sieved by a 200-mesh sieve, then uniformly mixed with the obtained 1.5% hot agarose solution according to the mass-to-volume ratio of 1:10, quickly poured into a glass mold, cooled to room temperature, cut into a plurality of wafers, and stored in a culture dish filled with ultrapure water at 4 ℃.

Further, the filtering membrane is a polyethersulfone circular filtering membrane with the diameter of 25mm, the thickness of 0.14mm and the pore diameter of 0.45 um.

Furthermore, the inner diameter of the diffusion film is 25mm, the thickness of the diffusion film is 0.8mm, and the mass of the diffusion film is 0.377-0.383 g.

Further, the adsorption film has an inner diameter of 25mm, a thickness of 0.5mm and a mass of 0.249-0.251 g.

Further, the DGT shell is washed by methanol and soaked in pure water, and the DGT shell is obtained by sucking the pure water with dust-free paper in use.

In a second aspect of the present invention, a method for passively monitoring antibiotic content in aquaculture water in situ by using the DGT device comprises the following steps:

placing a plurality of DGT devices in a plurality of culture water containers with antibiotic concentration of 0.27 ng/mL-0.33 ng/mL and pH value of 7.0-8.5, sealing and packaging the culture water containers with tinfoil, placing the culture water containers in a 25 ℃ constant temperature shaking table with the rotating speed of 120-140 r/min, taking out a certain DGT device in each container for 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h and 6h respectively, and taking out an adsorption film;

(ii) placing the taken adsorption membrane in an elution test tube filled with methanol solution for ultrasonic treatment for 15-20 min, removing the adsorption membrane, and blowing and concentrating elution liquid nitrogen to 50ul (V)_e) Determining the concentration value (C) of the antibiotic in the eluate_e)；

(iii) firstly, calculating the cumulant M on the adsorption film by the formula (1), obtaining a linear relation according to the change of the cumulant M of the antibiotic on the adsorption film along with time, obtaining a slope alpha by linear fitting, and then calculating the diffusion coefficient (D) of the DGT device in the aquaculture water body according to the formula (2), and representing the flux of the antibiotic in the aquaculture water body passing through the diffusion film in unit time; wherein:

elution efficiency of formula (1)

In the formula:

ce is the concentration of the antibiotic detected after the concentration of the eluent;

ve is 50 ul;

diffusion coefficient of formula (2)

In the formula:

α is the linear regression slope of the amount of antibiotic (ng) accumulated in the adsorption membrane over time(s);

△ g is the thickness (cm) of the diffusion membrane;

a is the area (cm) of the diffusion film²)；

C is the concentration of the antibiotic in water (ng/mL).

The diffusion coefficient D of the DGT in the aquaculture water body obtained by the method represents the flux of the antibiotics in the aquaculture water body passing through the diffusion membrane in unit time, and the result of measuring 1L of the antibiotic aqueous solution with the concentration of 0.3ng/mL by a solid phase extraction column is the concentration before adsorption (C)_SOLN)。

The antibiotic is quinolone antibiotic and sulfonamide antibiotic, including sulfamonomethoxine, ofloxacin, sulfamethoxazole, sulfamethazine, fleroxacin, trimethoprim, sulfamethazine, sulfadoxine, sulfapyridine, sulfadimethoxine and sulfachlorpyridazine.

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

(1) the DGT device is assembled by using XDA-1 resin as an adsorption membrane material and agarose gel as a diffusion membrane material and the prepared adsorption membrane, diffusion membrane and polyether sulfone circular filter membrane. The XDA-1 resin has the remarkable characteristics of stable structure, high porosity, large specific surface area, large adsorption capacity and the like, and has good adsorption effect when used for adsorbing antibiotics in the aquaculture water body.

(2) In the invention, the high stability of the in-situ adsorption effect is less influenced by conditions such as environmental pH, ionic strength and the like, the accuracy of a monitoring result is ensured, the detection of low-concentration antibiotics can be realized through the high capacity of the adsorption film, the XDA-1 resin serving as an adsorption material has no harm to the environment, the raw materials are easy to obtain, the preparation is simple, and the method is suitable for popularization and application.

(3) The method not only fills the blank of in-situ passive monitoring of the low-concentration antibiotic content in the aquaculture water body, but also can achieve the monitoring effect in a short time, and the measured diffusion coefficient can be calibrated by using a formula and is suitable for the actual aquaculture water body at the temperature of 15-40 ℃.

Drawings

FIG. 1 shows the concentration (C) detected in the DGT device_DGT) Detecting the concentration (C) by the conventional method_SOLN) (initial concentration of aqueous solution 0.3 ng/mL; t ═ 6 h).

Fig. 2 is a schematic diagram of the structure of a DGT device.

Detailed Description

The present invention is described in detail below with reference to examples, which will assist those skilled in the art in further understanding the present invention, but are not intended to limit the present invention in any way. It should be noted that it would be apparent to those skilled in the art that several modifications and improvements can be made without departing from the inventive concept. All falling within the scope of the present invention.

A DGT device for normal position passive monitoring antibiotic content in aquaculture water body includes: the DGT shell is positioned on two sides of the composite mold interlayer, the composite mold interlayer sequentially comprises an adsorption film, a diffusion film and a polyether sulfone circular filter film, the adsorption film, the diffusion film and the filter film are in a circular shape, the inner diameters of the adsorption film, the diffusion film and the filter film are the same, and the thickness ratio of the adsorption film to the diffusion film to the filter film is 0.28:1.6: 1. A filter membrane (polyethersulfone round filter membrane with diameter of 25mm, thickness of 0.14mm and aperture of 0.45um) and a DGT shell. Both the polyethersulfone circular filter membrane and the DGT shell are commercial products, and both XDA-1 resin and agarose are common commercial products.

The diffusion film is prepared by the following preparation method: 0.60g of agarose was weighed into a 100mL beaker, 40mL of ultrapure water was added, and then it was heated at a rate of 40 ℃/min to 400 ℃ until the whole solution was transparent, to prepare a 1.5% hot agarose solution, which was then immediately poured into a glass mold having a spacing of 0.8 mm. The mold selects two white glass sheets with the specification of 15cm long and 8cm wide, the middle of the white glass sheets is separated by a polytetrafluoroethylene thin plate which is cut into a concave shape in advance so as to control the thickness of the film to be 0.8mm, three sides of the mold are clamped by clamps, and one side of the mold is reserved for filling. And (3) pouring the hot agarose solution, cooling to room temperature, removing glass, cutting the cooled diffusion membrane into a circular shape by using a stainless steel circular knife with the inner diameter of 25mm, storing the membrane in a culture dish containing ultrapure water, and storing in a refrigerator at 4 ℃, wherein the mass of each diffusion membrane is controlled to be 0.38 +/-0.003 g.

The adsorption film is prepared by the following preparation method: the adsorption membrane material XDA-1 resin is fully washed by ultrapure water before use, then soaked for 10-20 minutes by using a small amount of methanol, washed by the ultrapure water after being repeated for 1-2 times, dried by dust-free paper, ground, sieved by a 200-mesh sieve and stored in a 100mL beaker. 1g of XDA-1 resin was uniformly mixed with 10mL of the hot agarose solution (1.5%) prepared in S1, and immediately poured into a glass mold while it was hot to prepare an adsorption membrane (except that the thickness of the membrane was 0.5mm, the thickness of the membrane was the same for all molds and methods). Selecting a stainless steel circular knife with the inner diameter of 25mm to cut the adsorption film into a circular shape, storing the film in a culture dish filled with ultrapure water, and storing the film in a refrigerator at 4 ℃, wherein the mass of each adsorption film is controlled to be 0.25 +/-0.01 g.

Prior to assembly, the DGT housing was rinsed with methanol and then soaked in pure water. When in use, the DGT shell is sucked dry by using dust-free paper. The DGT base is placed on a table board, the adsorption film, the diffusion film and the filtration film are sequentially stacked on the base by using plastic tweezers, and then the shell cover is covered. Pressing with palm strength or pressing with two thumbs on both sides to obtain the DGT device. After the preparation, the mixture is put into a beaker filled with ultrapure water and is stored in a refrigerator at 4 ℃.