CN-121978250-A - Method for analyzing chlorinated paraffin in environment or food sample

CN121978250ACN 121978250 ACN121978250 ACN 121978250ACN-121978250-A

Abstract

The invention discloses a method for analyzing chlorinated paraffin in an environment or food sample. And analyzing the environment or the short-chain chlorinated paraffin and the medium-chain chlorinated paraffin in the food sample by adopting a comprehensive two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry. The technology can effectively distinguish co-outflow components in complex matrixes through orthogonal separation under a unit mass resolution mode, and can rapidly and accurately acquire characteristic ion response information of a target chlorinated paraffin homolog group (C10-C17). The method has the detection limit reaching the level of nano gram/gram (ng/g), has higher sensitivity, accuracy and precision, can fully cover and accurately quantify the conventional C10-C17 chlorinated paraffin in the environment or food samples, and effectively meets the actual requirements of fully analyzing the short-chain and medium-chain chlorinated paraffin in the current environment and food monitoring.

Inventors

GAO LIRONG
WANG YUQI
ZHENG MINGHUI
WENG JIYUAN
LI CHANGLIANG

Assignees

中国科学院生态环境研究中心

Dates

Publication Date: 20260505
Application Date: 20260313

Claims (10)

1. A method for analyzing chlorinated paraffin in an environment or a food sample by using a comprehensive two-dimensional gas chromatography-electron capture negative chemical ion source-quadrupole mass spectrometry technology, which comprises the following steps: 1) Enriching and extracting chlorinated paraffin components in an environment or food sample, and further purifying to obtain a sample to be detected; 2) Detecting chlorinated paraffin in the sample to be detected by adopting full two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry; 3) Obtaining response information of each component in the chlorinated paraffin by adopting characteristic ion extraction and retention time; 4) The components in the chlorinated paraffin were quantitatively analyzed by a standard curve method based on chlorine content correction.
2. The method according to claim 1, wherein the operation of enriching, extracting and further purifying chlorinated paraffin components in the environmental or food sample to obtain a sample to be tested comprises: Drying the environment or food sample to constant weight and grinding to obtain sample powder; Extracting chlorinated paraffin components in the sample powder by adopting an accelerated extraction method to obtain an extract; Concentrating, purifying, re-concentrating and fixing the volume of the extract to obtain a sample to be detected.
3. The method of claim 1, wherein detecting chlorinated paraffin in the sample to be measured using full two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry comprises: injecting the sample to be detected into a full two-dimensional gas chromatograph-electron capture negative chemical ion source quadrupole mass spectrometer; The components of chlorinated paraffin in a sample to be detected are subjected to orthogonal separation through two chromatographic columns with different polarities of full two-dimensional gas chromatography and a thermal modulator, then enter an electron capture negative chemical ion source for ionization, and are detected through quadrupole mass spectrometry, so that a mass spectrum is obtained.
4. The method of claim 1, wherein the act of obtaining response information for each component of the chlorinated paraffin using characteristic ion extraction and two-dimensional retention time comprises: carrying out qualitative analysis on the mass spectrogram by using data processing software special for full two-dimensional chromatography-quadrupole mass spectrometry, and extracting characteristic [ M-Cl ] - ions of each component in the chlorinated paraffin as qualitative ions and quantitative ions in a preset characteristic mass number (M/z) window; and obtaining the response area of each component of the chlorinated paraffin in the sample to be detected according to the retention time of each homolog group in the standard solution in the two-dimensional chromatographic space.
5. The method according to claim 1, wherein the operation of quantitatively analyzing each component in the chlorinated paraffin by a standard curve method based on chlorine content correction comprises: Preparing chlorinated paraffin standard solutions with different chlorine contents, and adding an equivalent amount of recovered internal standard and sample injection internal standard into the chlorinated paraffin standard solutions; analyzing the standard solution containing the internal standard by adopting the comprehensive two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry technology; Adopting characteristic [ M-Cl ] - ion extraction and retention time to obtain the relative peak area and actually measured chlorine content between chlorinated paraffin components and an internal standard substance in the standard solution, combining the content of the chlorinated paraffin standard solution to obtain a relative response factor, and drawing a standard curve; According to the response area and the actually measured chlorine content of each component of the chlorinated paraffin in the sample to be detected, combining the linear equation of the standard curve to obtain the response factor of the chlorinated paraffin in the sample to be detected; And calculating the total content of the chlorinated paraffin and the content of each component of the chlorinated paraffin in the sample to be detected according to the response factor of the chlorinated paraffin in the sample to be detected.
6. The method of claim 2, wherein the step of determining the position of the substrate comprises, The environmental or food sample comprises a food sample and an air sampling filter membrane; The filler of the extraction tank in the accelerated extraction method is diatomite, trans-chlordane used as an internal standard is added in the extraction tank, and the extraction solvent comprises a mixture of dichloromethane and n-hexane; the extraction temperature of the accelerated extraction method is 100+/-5 ℃, the pressure is 10342+/-100 KPa ℃, the heating time is 5+/-1 min, the static time is 10+/-2 min, the flushing volume is 60%, and the purging time is 60+/-5 s.
7. The method of claim 2, wherein concentrating, purifying, re-concentrating and sizing the extract comprises: Concentrating the extract by using a rotary evaporator, and transferring the extract to a chromatographic column for purification; Then the solution after purification is concentrated again by using a rotary evaporator and a nitrogen blowing instrument; And adding hexachlorocyclohexane serving as a sample injection internal standard into the re-concentrated solution, and fixing the volume by using cyclohexane to obtain the sample to be detected.
8. The method of claim 3, wherein the conditions of the all two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry technique comprise: The chromatographic column system comprises a first dimension chromatographic column which is a nonpolar DB-5MS column, and a second dimension chromatographic column which is a medium polarity BPX-50 column; Column temperature program, initial temperature 100 ℃ is kept at 1 min ℃, temperature is increased to 140 ℃ at the speed of 10 ℃ per min, and then temperature is increased to 310 ℃ at the speed of 1.5 ℃ per min and kept at 5 min; the sample injection condition is that the sample injection mode is no-split sample injection, the sample injection volume is 1.0 mu L, and the sample injection port temperature is 280 ℃; The carrier gas is high-purity helium with purity more than or equal to 99.999 percent and constant flow rate of 0.8 mL/min; the modulation condition is that the modulator adopts a thermal modulation mode, and the modulation period is 7 s; The mass spectrum condition is that the ion source is an Electron Capturing Negative Ionization (ECNI) source, the temperature of the ion source is 200 ℃, the temperature of a transmission line is 280 ℃, the reaction gas is methane, the mass acquisition range is 50-1200 m/z, the scanning mode is full scanning or selective ion monitoring, and the mass resolution is unit mass resolution.
9. The method of claim 5, wherein the relative peak areas and measured chlorine content of each component in the chlorinated paraffin standard solution are calculated according to the following strategy: firstly, dividing chlorinated paraffin homologues with the same two-dimensional retention time characteristics in a mass spectrogram into a plurality of homologue groups, and calculating peak areas of the groups; Chlorinated paraffin homolog group relative response value = chlorinated paraffin homolog group peak area +.r.recovery internal standard peak area; Chlorinated paraffin sample measured chlorine content = Σ (peak area of each homolog group x theoretical chlorine content of the group)/(Σ peak area of each homolog group); summing the relative response values of all homolog groups of the chlorinated paraffin to obtain a total relative response value, and calculating the total response factor of the standard solution according to the following formula: Chlorinated paraffin total response factor = chlorinated paraffin total relative response value +.chlorinated paraffin standard solution total concentration; And performing linear fitting by taking the chlorinated paraffin total response factor as an ordinate and the chlorinated paraffin actual measurement chlorine content as an abscissa to obtain the chlorine content correction standard curve.
10. The method of claim 1, wherein, The components of the chlorinated paraffin comprise C n H 2n+2-m Cl m ; wherein n represents the number of carbon atoms and is an integer of 10 to 17; m represents the number of chlorine atoms and is an integer 5~n.

Description

Method for analyzing chlorinated paraffin in environment or food sample Technical Field The invention belongs to the technical field of analysis and test, and particularly relates to a method for analyzing chlorinated paraffin in an environment or a food sample, in particular to a method for analyzing chlorinated paraffin in an environment or a food sample by adopting a full two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry combined technology. Background Chlorinated paraffin (Chlorinated Paraffins, CPs for short) is a kind of artificially synthesized linear alkane chloro derivative, which is used as an important industrial raw material and widely applied to the production of products such as flame retardants, plasticizers, lubricating oil, metal cutting fluids and the like. Chlorinated paraffins can be classified into short chain (SCCPs, C 10-C13), medium chain (MCCPs, C 14-C17) and long chain (LCCPs, C18 and above) according to the carbon chain length. Among them, SCCPs and MCCPs have been listed as persistent organic pollutants by the Stockholm convention and are severely restricted worldwide due to their persistence, bioaccumulation, toxicity and long distance migration potential. Despite the huge cumulative yields of chlorinated paraffins, due to the numerous specifications of industrial products, the varying distribution of chlorine content, and the lack of effective recovery process supervision, a large number of CPs enter the environmental medium, which constitutes a potential threat to the ecosystem and human health. Accurate detection and quantification of Chlorinated Paraffins (CPs) in food products has been a serious challenge in analytical chemistry, CPs are complex mixtures of thousands of homologs and isomers, each component being extremely similar in physicochemical properties, resulting in difficulty in achieving efficient separation by conventional one-dimensional chromatography, often causing severe peak overlapping and co-outflow phenomena, and difficulty in distinguishing the co-outflow different components even in conjunction with mass spectrometry, in conventional mass spectrometry, although the Electron Capture Negative Ionization (ECNI) mode has high selectivity, it is faced with other organic chlorides such as toxaphene, polychlorinated biphenyl, etc. present in complex matrices of food products (such as fats, grains, meats, condiments, etc.), and lipids, substances, and methods of use thereof, The method is characterized in that the method comprises the steps of mixing a plurality of standard substances with a standard substance, mixing the standard substance with an ionization source, and mixing the standard substance with the ionization source to obtain a mixture, wherein the mixture is mixed with a plurality of standard substances, and the mixture is mixed with a plurality of ionization sources to obtain a mixture, wherein the mixture is mixed with the mixture, and the mixture is mixed with the mixture to obtain a mixture, wherein the mixture is mixed with the mixture to obtain a mixture, and the mixture is mixed with the mixture to obtain the mixture The interference of protein and other halogenated organic matters and other matrixes is more complex than that of environmental samples, the pretreatment purification difficulty is further increased, the detection sensitivity and the stability of the result are seriously affected, for example, a large amount of lipid in high-oil food is easy to co-extract with CPs, and trace pigments and plant macromolecules in low-fat food (vegetables and grains) can inhibit detection signals. Therefore, development of a method combining a full two-dimensional chromatography technology with strong separation capability and a targeted quantitative correction strategy is needed to realize accurate analysis of chlorinated paraffin in food on a conventional mass spectrum platform, and provide technical support for CPs pollution risk assessment and food safety management in food. Disclosure of Invention In view of the above, the present invention provides a method for analyzing chlorinated paraffin in an environment or a food sample by full two-dimensional gas chromatography-electron capturing negative chemical ion source quadrupole mass spectrometry, so as to at least partially solve the above technical problems. In order to solve the technical problems, the technical scheme provided by the invention is as follows: A method for analyzing chlorinated paraffin in an environment or a food sample by full two-dimensional gas chromatography-electron capture negative chemical ion source quadrupole mass spectrometry, comprising the following steps: 1) Enriching and extracting chlorinated paraffin components in an environment or food sample, and further purifying to obtain a sample to be detected; 2) Detecting chlorinated paraffin in the sample to be detected by adopting full two-dimensiona