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CN-122016995-A - Nanometer micro-plastic rapid screening method based on MALDI-TOF mass spectrum

CN122016995ACN 122016995 ACN122016995 ACN 122016995ACN-122016995-A

Abstract

The invention relates to a nano micro-plastic rapid screening method based on MALDI-TOF mass spectrum, which comprises the steps of preprocessing solid samples such as garbage, soil and the like and liquid samples such as percolate, underground water and the like, enriching nano-level micro-plastic solid particles, adding an organic solvent into the solid particles for dissolving to obtain a micro-plastic sample solution, respectively dissolving an imaging matrix and a cationizing agent into the organic solvent to form a matrix solution and a cationizing agent solution, mixing the three according to the mass ratio of (9-11) to 1, sampling the mixed solution on a target plate for natural crystallization, and collecting a spectrum and analyzing characteristic signals through a MALDI-TOF mass spectrometer. The method breaks through the limitation that the prior art can only detect the microplastic with large particle size, realizes the accurate identification of the nano-grade microplastic with particle size smaller than 1 micron, widens the range of screening media, greatly shortens the analysis period, and meets the requirements of rapid and accurate screening of new pollutant risk prevention and control.

Inventors

  • ZHOU LEI
  • HU YIXIN
  • Feng Qijia
  • ZHANG YUQUAN
  • DUN JUNLING
  • Sui qian
  • YU XIA
  • PENG CHENG

Assignees

  • 华东理工大学
  • 岛津企业管理（中国）有限公司

Dates

Publication Date
20260512
Application Date
20260120

Claims (10)

  1. 1. The nano-micro plastic rapid screening method based on MALDI-TOF mass spectrum is characterized by comprising the following steps of: S1, preprocessing a solid sample and a liquid sample of a history irregular landfill to obtain solid particles enriched with nano-grade micro plastics, wherein the solid sample is a garbage sample or a soil sample, and the liquid sample is a percolate sample or a groundwater sample; S2, taking the solid particles, and adding an organic solvent for dissolution to obtain a micro-plastic sample solution; S3, dissolving an imaging matrix in the organic solvent to form a matrix solution, dissolving a cationizing agent in the organic solvent to form a cationizing agent solution, and mixing the matrix solution, namely a micro plastic sample solution, namely a cationizing agent solution= (9-11): (9-11): 1 in a mass ratio to obtain a mixed solution; s4, taking the mixed solution to sample on a target plate, and naturally crystallizing under the environmental condition; S5, placing the crystallized target plate into a MALDI-TOF mass spectrometer for spectrum acquisition, and judging whether nano-grade microplastic exists in the sample by analyzing the mass spectrum characteristic signals.
  2. 2. The rapid screening method of the nanometer micro-plastic according to claim 1, wherein in the step S1, the pretreatment of the solid sample comprises the steps of distributing sampling points through plane distribution points and/or vertical distribution points, collecting the sample through a section method or a drilling method, subjecting the collected sample to a shrinkage process, drying the shrinkage sample to constant weight at normal temperature to 60 ℃, screening the dried sample through a 5-20 mesh screen, and collecting undersize solid particles.
  3. 3. The rapid screening method for the nanometer microplastic according to claim 2 is characterized in that the plane distribution point adopts a grid method or a partition method, the vertical distribution point collects surface layer samples, middle layer samples and deep layer samples according to different depths, the collection depth of the surface layer samples is 0-0.8 m, the collection depth of the middle layer samples is 0.5-6 m, and the collection depth of the deep layer samples is more than 6 m.
  4. 4. The rapid screening method of nano-micro plastics according to claim 2, wherein the division is a quartering method.
  5. 5. The rapid screening method for the nano-micro plastic according to claim 1, wherein in the step S1, the pretreatment of the liquid sample comprises the steps of arranging sampling points through a collecting system sampling point, a processing facility sampling point or an environment monitoring point, collecting the liquid sample, screening the liquid sample through a 500-700-mesh screen to intercept solid particles, flushing the screen through a saturated sodium chloride solution, collecting a mixture of the flushed solid particles and flushing liquid, separating the solid particles in the mixture from the liquid, and drying the mixture to constant weight to obtain the solid particles.
  6. 6. The rapid screening method of nanomicroplastics according to claim 5, wherein the collection system sampling points comprise observation wells and outlets of an equalizing basin, a collection well or a drainage blind ditch, the treatment facility sampling points comprise inlets and outlets of a leachate treatment facility, and the environmental monitoring points comprise groundwater monitoring wells or surface water drains.
  7. 7. The rapid screening method of nano-microplastic according to claim 1, wherein the organic solvent is tetrahydrofuran, and the concentration of the microplastic sample solution is 3-8mg/mL.
  8. 8. The rapid screening method of nano-micro plastic according to claim 1, wherein the imaging matrix is DCTB, and the concentration of the matrix solution is 15-25mg/mL.
  9. 9. The rapid screening method of nano-micro plastics according to claim 1, wherein the cationizing agent is silver trifluoroacetate, and the concentration of the cationizing agent solution is 3-8mg/mL.
  10. 10. The rapid screening method of nano-microplastic according to claim 1, wherein the mass ratio of the matrix solution, the microplastic sample solution and the cationizing agent solution is 10:10:1, and the nano-grade microplastic is plastic particles with the particle size smaller than 1 micrometer.

Description

Nanometer micro-plastic rapid screening method based on MALDI-TOF mass spectrum Technical Field The invention relates to microplastic detection in environmental monitoring, in particular to a nano-microplastic rapid screening method based on MALDI-TOF mass spectrum. Background Microplastic (microplastics, MPs) has become one of the core tasks in the new pollutant remediation field as a new class of pollutant of great interest, its emissions source identification and risk management. Historically irregular landfills have resulted from the accumulation of large amounts of plastic waste and the general lack of an effective impermeable system, which leads to the gradual degradation of plastics under the action of long-term environment to form microplastic, and continuously migrate into soil-groundwater environment along with percolate, resulting in multi-medium combined pollution, which becomes a main contribution source for soil-groundwater microplastic pollution. According to statistics, by 2020, the number of the historical irregular landfill sites in China reaches 2.4 ten thousand, the garbage storage amount is about 80 hundred million tons, which is equivalent to 30 times of the daily garbage cleaning and transporting amount in China, and the landfill sites have wide distribution range, unclear pollution base and extremely large treatment difficulty. However, the current micro-plastic pollution research on the history irregular landfill site still has obvious short plates that the formation mechanism of nano-scale micro-plastic in a garbage-leachate-soil-groundwater multi-medium system is not clear, the migration and transformation rule lacks system cognition, and the environmental health risk assessment technology is also in need of improvement. Therefore, the development of the micro-plastic rapid screening technology suitable for the complex multi-medium system has important practical significance and scientific value for revealing the occurrence characteristics of the micro-plastic, defining the pollution migration path and evaluating the environmental health risk. The rapid and accurate quantitative analysis method is established as a basis for realizing effective identification of the microplastic in the multi-medium system. In the development process of the micro-plastic detection technology, the traditional method mostly adopts pretreatment means such as density separation, digestion and the like, and then the sampling detection is carried out through visual observation or infrared spectrum, but the method has high misjudgment rate, and especially in complex environment samples, the micro-plastic and other impurities are difficult to effectively distinguish, so that accurate identification is limited. In order to solve the problem, related research teams at home and abroad develop qualitative and quantitative methods such as thermal cracking-gas mass spectrometry technology, spectral image recognition and the like, the technology makes progress in improving the analysis accuracy of specific types of microplastic such as polystyrene, polyvinyl chloride and the like, and provides a new thought for the recognition of the microplastic in complex environment samples. The improved technology has the obvious defects that firstly, the analysis period is overlong, wherein the single sample analysis period of the thermal cracking-gas mass spectrometry technology is as long as 3-5 hours, the single sample analysis period of the spectral image identification is 1-2 hours, the requirement of rapid screening of a large number of samples is difficult to meet, secondly, the application range is narrow, the spectral image identification can only detect micro plastics with the size of more than 50 mu m, the micro plastics with the size of less than 50 mu m and nano-grade micro plastics can not be effectively identified, thirdly, the detection error is still higher, the error rate of the spectral image identification is about 10% -15%, and the requirement of accurate pollution assessment is difficult to meet. Disclosure of Invention The invention aims to solve the problems that the analysis period is long, the application range is narrow and the nano-grade micro-plastic cannot be accurately screened in the prior art, and provides a nano-grade micro-plastic rapid screening method based on MALDI-TOF mass spectrum. The rapid screening method for the nano-microplastic based on the MALDI-TOF mass spectrum comprises the following steps of S1, preprocessing a solid sample and a liquid sample of a history irregular landfill to obtain solid particles enriched with nano-microplastic, wherein the solid sample is a garbage sample or a soil sample, the liquid sample is a percolate sample or a groundwater sample, S2, taking the solid particles, adding an organic solvent to dissolve the solid particles to obtain a microplastic sample solution, S3, dissolving an imaging matrix in the organic solvent to form a matrix solution, dissol