阅读说明：本技术 一种嗅味水样预处理的装置及其运行工艺 (Device for pretreating smelly water sample and operation process thereof ) 是由 郭庆园 丁成 李朝霞 杨百忍 闵敏 远野 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种嗅味水样预处理的装置及其运行工艺,该装置包括通过管道依次相连的高纯氮气瓶、水样罐、一级吸收罐和二级吸收罐,其中,所述水样罐、一级吸收罐和二级吸收罐的底部均设有微孔曝气装置,所述一级吸收罐和二级吸收罐内装有吸收试剂。本发明的装置可以实现对嗅味水样中致嗅化合物的有效萃取和收集,有效解决了异味物质气相色谱-质谱分析时背景物质干扰大的难题。该装置操作简单,成本较低,效率较高,普遍适用于异味水环境中相关化合物的预处理分析。(The invention discloses a device for pretreating a smelly water sample and an operation process thereof. The device provided by the invention can realize effective extraction and collection of the odor-causing compounds in the odor water sample, and effectively solves the problem of large interference of background substances during gas chromatography-mass spectrometry of the odor substances. The device is simple to operate, low in cost and high in efficiency, and is generally suitable for pretreatment analysis of related compounds in the odorous water environment.)

1. The utility model provides a smell taste water sample preprocessing's device, its characterized in that includes high-purity nitrogen cylinder, water sample jar, one-level absorption tank and the second grade absorption tank that links to each other in proper order through the pipeline, wherein, the bottom of water sample jar, one-level absorption tank and second grade absorption tank all is equipped with micropore aeration equipment, be equipped with absorbent in one-level absorption tank and the second grade absorption tank.

2. The device for pretreating smelly water sample according to claim 1, wherein the absorption reagents in the primary absorption tank and the secondary absorption tank are absorption reagents with the same or different polarities.

3. The device for pretreating smelly water samples according to claim 2, wherein when the absorption reagents in the primary absorption tank and the secondary absorption tank are absorption reagents with different polarities, the absorption reagent in the primary absorption tank is a weak polarity reagent, and the absorption reagent in the secondary absorption tank is a strong polarity reagent.

4. The device for pretreating smelling water sample according to claim 1, wherein the pipeline is a polytetrafluoroethylene gas transmission pipe.

5. The operation process of the device for pretreating the smelly water sample according to claim 1, wherein the smelly water sample is placed into a water sample tank, the opening degree of a high-purity nitrogen bottle is adjusted until the liquid surface in the water sample tank shakes slightly, the high-nitrogen gas with the smelly substances is sequentially introduced into a primary absorption tank and a secondary absorption tank filled with absorption reagents through a microporous aeration device, the smelly compounds are desorbed and adsorbed for 1h through aeration, the absorption reagents are dehydrated, and finally the sample is transferred out of the device for storage.

Technical Field

The invention belongs to the technical field of environmental protection, and particularly relates to a device for pretreating a smelly water sample and an operation process thereof.

Background

The smell threshold of smelly substances generating smell in drinking water is lower and is often lower than the detection limit of related instruments, but human body smell sense organs are very sensitive and can sense the smell of water. Therefore, the selection of a proper pretreatment concentration method is very important for the identification, analysis and determination of the odor substances in the water body. The common pretreatment concentration method for drinking water at present mainly comprises a solid phase extraction method, a solid phase microextraction method, a stirring rod adsorption extraction method, a simultaneous distillation extraction method, a liquid-liquid extraction method and the like.

1. Solid phase micro-extraction: the solid phase micro extraction technology is a sample pretreatment and enrichment technology which is started in the 90 s of the 20 th century, the device is similar to a micro sample injection needle of gas chromatography, the extraction head is that a quartz fiber is coated with a corresponding coating, a thin stainless steel pipe is sleeved outside to protect the quartz fiber from being broken, the fiber head can extend and retract in the steel pipe, when in use, the fiber coating is directly immersed in water or organic matters in a headspace extraction water sample, after balance, the needle head is taken out, and is injected into a GC sample injection port to enable the fiber coating to rapidly analyze the adsorbed smelly substances at high temperature. However, due to the characteristics of less water sample, no concentration and the like, the fiber coatings with different polarities need to be selected according to the polarity of the object to be detected, namely the polar coating extracts polar compounds and the nonpolar coating extracts nonpolar compounds, so that the fiber adsorption capacity is limited indirectly, the extraction fibers need to be replaced when the total substance analysis is carried out, and the defects of time and labor waste and the like are caused.

2. And (3) stirring rod adsorption extraction: the principle of the stirring rod adsorption extraction is basically consistent with that of solid-phase microextraction, the main component is a magnetic stirrer wrapped by glass, the surface of the glass is coated with a polydimethylsiloxane layer with the thickness of about 0.5mm, the stirrer is placed in a sample during analysis and stirred for a certain time, the coating is allowed to adsorb organic components, then the stirrer is placed in a thermal analysis device, and gas chromatography-mass spectrometry analysis and detection are carried out after analysis. However, the currently applied stirring rod adsorption extraction coating is only made of nonpolar PDMS material, is only suitable for semi-volatile organic compounds, and has limited adsorption capacity.

3. Distillation and extraction: the simultaneous distillation and extraction is a combination of distillation and liquid-liquid extraction, and water sample and extraction solvent are respectively placed in different flasks to be heated, and organic matter in the water sample is extracted by using solvent steam. The general procedure is to distill and extract 3L of water sample with 50mL of dichloromethane for 2h, then concentrate to several hundred microliters for analysis using a K-D concentrator. However, the extraction capacity is limited, the detection limit is high, and the conversion of the smelly compounds can be caused in the high-temperature distillation process, so that the target smelly compounds are lost.

4. Liquid-liquid extraction: liquid-liquid extraction (LLE) is a method for extracting organic matters in a water sample by using an organic solvent, the method adopts multiple times of extraction, an extracting agent is selected according to different target matters, common extracting agents are normal hexane and dichloromethane, and an extraction liquid containing the target organic matters is concentrated by adopting a rotary evaporation and nitrogen blowing mode. Most organic substances in a water sample, including volatile, semi-volatile and nonvolatile organic substances, can be extracted simultaneously by liquid-liquid extraction, a large number of compounds can be detected during gas chromatography-mass spectrometry, several specific volatile smelly substances are often required to be found out from thousands of chromatographic peaks, and great difficulty is brought to screening, identification, detection and analysis of target smelly compounds.

The odor substance in the water environment is generally volatile micromolecular organic matter, the odor threshold concentration is low, and the odor compound concentration in the water body is at the level of ng/L-mug/L, so that the obvious odor is caused. In order to effectively identify, analyze and detect the smelly compounds in water, the smelly water sample must be subjected to a concentration pretreatment prior to instrumental analysis. In the process of pretreating and concentrating the smelly water sample, a large amount of other background substances without peculiar smell are extracted while trace smelly substances are extracted, and the heating ring section of certain pretreatment and concentration technologies can cause the denaturation and transformation of smelly compounds, thereby bringing great difficulty to the identification, analysis and detection of the smelly substances in the smelly water sample, and the pretreatment technologies have low recovery rate and are time-consuming and labor-consuming.

Disclosure of Invention

The invention provides a device for pretreating an smelly water sample and an operation process thereof, aiming at the problems of large interference of background substances, low recovery rate, time and labor waste and the like in the prior smelly water sample pretreatment technology.

The invention is realized by the following technical scheme:

the utility model provides a smell device of taste water sample preliminary treatment, includes high-purity nitrogen cylinder, water sample jar, one-level absorption tank and the second grade absorption tank that links to each other in proper order through the pipeline, wherein, the bottom of water sample jar, one-level absorption tank and second grade absorption tank all is equipped with micropore aeration equipment, be equipped with absorbent in one-level absorption tank and the second grade absorption tank.

Preferably, the absorption reagents in the primary absorption tank and the secondary absorption tank are absorption reagents with the same or different polarities.

Preferably, when the absorption reagents in the primary absorption tank and the secondary absorption tank are absorption reagents with different polarities, the absorption reagent in the primary absorption tank is a weak-polarity reagent, and the absorption reagent in the secondary absorption tank is a strong-polarity reagent.

Preferably, the pipeline is a polytetrafluoroethylene gas transmission pipe.

An operation process of a device for pretreating smelly water samples comprises the following steps: putting a smelly water sample into a water sample tank, adjusting the opening of a high-purity nitrogen bottle until the liquid surface in the water sample tank slightly shakes, sequentially feeding the high-nitrogen gas wrapped with smelly substances into a primary absorption tank and a secondary absorption tank filled with absorption reagents through a microporous aeration device, carrying out aeration desorption-adsorption on the smelly compounds for 1h, carrying out dehydration treatment on the absorption reagents, and finally transferring the sample out of the device for storage.

The invention has the following beneficial effects:

the process of human body perceiving the water environment peculiar smell is that the smelly compound in the water body penetrates through a gas-liquid interface to the air and then diffuses to the olfactory organ of the human body, so that the human body perceives various types and strength of smelly smell. The invention provides a pretreatment device capable of effectively extracting smelly compounds in smelly water samples, which directly adopts a technology of high-purity nitrogen stripping-organic reagent absorption of volatile smelly compounds, and compared with the traditional liquid-liquid extraction, co-distillation extraction and the like, the pretreatment device can be used for simultaneously extracting all organic compounds in water samples, and the technical scheme only absorbs the volatile (smelly) compounds blown out by the high-purity nitrogen stripping, so that the problems of difficult identification, analysis and detection of the smelly compounds caused by large background matrix interference during gas chromatography-mass spectrometry in the traditional pretreatment technology are solved. The device provided by the invention is provided with a two-stage absorption tank structure, and can effectively absorb the volatile (smelly) compounds blown off. In example 2, the technical scheme of the invention is successfully applied to the identification and analysis of the smelly compounds of a certain fishy smell and earthy mildew taste drinking water source, 6 smelly peaks of aroma, fishy smell, cucumber smell, aroma, earthy mildew taste and aroma are successfully detected, and 6 corresponding smelly substances of butyl butyrate, 2-nonenal, 2, 6-nonadienal, undecylenic aldehyde, geosmin and ionone are identified and confirmed. Compared with the traditional liquid-liquid extraction pretreatment technology, the sensory gas chromatography-mass spectrometry analysis of the sample treated by the technical scheme detects 4 more smelly (compounds), the background base line of the chromatogram is lower, the difference between the detected substance chromatographic peak and the background base line is obvious, and the impurity substances of the sample injection matrix after pretreatment and concentration are fewer. The pretreatment device effectively solves the problem of large interference of background substances during gas chromatography-mass spectrometry of the peculiar smell substances. The method is simple to operate, low in cost, high in efficiency and generally suitable for pretreatment analysis of related compounds in the odorous water environment.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus of the present invention;

in fig. 1: 1. a high-purity nitrogen cylinder; 2. a pipeline; 3. a water sample tank; 4. a primary absorption tank; 5. a secondary absorption tank; 6. a microporous aeration device;

FIG. 2 is a diagram showing the results of the identification and analysis of the odorant after concentration by the aeration desorption-absorption pretreatment of example 2;

FIG. 3 is a graph showing the results of the identification and analysis of the odorant after concentration by pretreatment in comparative example 1.

Detailed Description

The invention is described in further detail below with reference to specific embodiments and with reference to the following drawings.