Abstract: Discuss liquid chromatography related techniques and their applications in residue analysis. The characteristics of solid phase extraction (SPE), liquid chromatography ( HPLC ) and liquid chromatography-mass spectrometry (LC/MS) for sample preparation are introduced, as well as veterinary drugs, pesticides and toxins in food and agricultural products. Application in the analysis of toxic and hazardous substances residues.
Key words: HPLC; SPE; liquid-mass spectrometry; veterinary drug residue; pesticide residue middle circle classification number 0657.63
The AppUcations of W aters SPE. HPLC and LC/MS Technology
On Residue Analysis in Food and Agro-preducts
Almract: The advantages of Waters products aRE introduced and the APPLicATION Waters SPE, HPLC and LC/MS technologes on residue analysis aIe described. The methods reviewed include extraction and analysis 0f veterinary drugs,pesticides,toxins and the other harmful residues in a variety 0f sample matrixes. The multiresidue technique is also discussed.
Key words: HPLC; SPE; LV/MS; rescues veterinary drugs; rescues pesticides.
1 Introduction Residue monitoring, as an important issue in food safety, requires the use of multiple sample preparation methods and analytical testing methods. The continuous development of high performance liquid chromatography and liquid chromatography- mass spectrometry has made it more and more widely used in the detection and analysis of toxic and hazardous substances of different types of veterinary drugs, pesticides and toxins. Unlike other liquid chromatography applications, residue analysis for food and agricultural products places high demands on sensitivity, reproducibility, and selectivity, often requiring the detection of trace amounts of residual material at ppb or lower levels in complex matrices. . If you want to achieve the above goals, you may not only need good sample preparation methods to purify complex food and agricultural products, concentrate target components, but also need to select high-performance, high-sensitivity HPLC or LC/MS systems for detection and analysis.
This paper will discuss the analysis of pesticides, veterinary drug residues, biotoxins and other toxic and harmful residues in food, feed and agricultural products from the aspects of solid phase extraction technology, HPLC and LC/MS technology.
2 Solid phase extraction technology for sample preparation High-efficiency extraction and purification of food and agricultural product samples to improve detection selectivity and sensitivity. Samples must be pre-treated regardless of LC, GC , LC/MS and slave instruments. Among many methods, solid phase extraction technology is one of the technologies that have developed zui in recent years and has become more and more widely used. Solid phase extraction (SPE) is a sample preparation technique based on the principle of liquid chromatography, using solid chromatography cartridges to purify the sample background or extract the target components in the solution. Compared with liquid-liquid extraction technology, SPE technology is easy to operate, high in extraction efficiency, low in solvent consumption, easy to automate, and easier to obtain high recovery results.
In 1978, Waters first commercialized SPE technology. The trademark of solid phase extraction product named sep-Pak was registered. Since then, Sep-Pak solid phase extraction technology has been widely used.
SPE technology solid phase extraction fillers are reversed, normal phase, ion exchange and other types, including Cl8, C8, C2, -NH2, -Diol, -CN, Silica, Flofisil, alumina, polymer matrix, anion / cation Exchange and a variety of adsorbents such as DNPH. In 1996, a new universal filler Oasis HLB and a dual-mechanical filler with high selectivity (such as OasisMCX/MAX- with both ion exchange and reversed-phase mechanisms) were introduced, which can be used for acidic, basic and neutral organic compounds. Extraction, as well as high selectivity of acidic or basic compounds, are separately extracted. The introduction of the new Oasis filler further expands the application of SPE technology and establishes new standards for SPE technology recovery, reproducibility and versatility.
In the detection of food and agricultural products and feed residues, SPE is used several times to achieve sample purification and target component enrichment. Antibiotics in meat (such as tetracyclines, chloramphenicol, etc.), sulfa drugs, quinolones, hormones (such as diethylstilbestrol), clenbuterol, furazolidone, nitrofurazone and other veterinary drugs; carbamate, organic phosphorus and other pesticides Aflatoxin, patulin and other toxins can be extracted by SPE means multi-residue analysis or matrix pre-dispersion extraction (MatrkSolid Phase Dispersion Extraction) and gel permeation chromatography (GPc) for sample preparation .
3 Liquid Chromatography: An important tool for residue detection HPLC can be used for the analysis of difficult to volatile, more polar substances. It is estimated that the GC method can only solve about 20% of organic matter analysis, and about 80% of organic matter can be analyzed by HPLC method. The characteristics of veterinary drugs make it generally suitable for HPLC analysis; many methods of pesticide residue analysis also use HPLC method. Unlike other conventional HPLC applications, residue analysis requires high sensitivity and reproducibility. High sensitivity can achieve good results for trace target components in complex matrices; high reproducibility is the basic guarantee for high confidence levels. To achieve the above objectives, an HPLC system needs to be optimized.
3.1 Sensitivity: Necessary conditions for residue analysis The sensitivity of chromatographic results is usually measured by the ratio of signal to noise (ie, signal-to-noise ratio). Therefore, the sensitivity can be improved by increasing the response value of the detection signal or reducing the noise. For HPLC systems, the increase in signal strength is primarily due to the performance of the detector.
The UV absorption characteristics of most substances make the UV detector a universal HPLC detector commonly used in multi-residue analysis. It is often used to quickly screen a variety of veterinary drugs or pesticide residues. Such as sulfa drug residues, tetracycline residues, furazolidone, chloramphenicol, tetracycline and so on. The dual-channel UV detector with patented trapezoidal slit cell design fully absorbs the energy of the xenon lamp and achieves highly sensitive detection results.
Fluorescence detectors with high sensitivity and selectivity are effective tools for residue analysis. * A carbamate AOAC method for multi-residue analysis uses an analytical method for post-column derivatization. Zui newly developed multi-wavelength fluorescence detector, unique axial illumination flow cell design, zui greatly reduced light scattering, effectively lengthening the length of the cell; the new xenon lamp used in the detector can also emit higher light energy The above optimized design provides unmatched high sensitivity fluorescence detection for low concentration samples.
Since most compounds do not have a natural fluorescence response, many methods using fluorescence detectors require post-column derivatization to produce or enhance the fluorescence response characteristics of the target component for high sensitivity detection. Using a HPLC system optimized for carbamate analysis, 11 carbamates and their metabolites can be analyzed simultaneously. The system can be used not only for high-sensitivity detection of carbamate residue residues, but also for a variety of residue analyses that require post-column derivatization-fluorescence detection or without the need to derivatize natural fluorescent materials. Woell et al. used post-column derivatization of this system. Fluorescence detection methods successfully analyzed some residues of glyphosate and its metabolites in vegetables, fruits, grains and water.
Trace analysis of aflatoxin in cereals, peanuts and other matrices can also be performed using the above system. Detector-optimized systems can easily reach the ppt level of detection.
3.2 Multi-residue analysis and compound confirmation: Making full use of the spectral function of the photodiode matrix detector Photodiode matrix detector (PDA) as one of the UV detectors can not only obtain the chromatographic information, but also obtain the real-time spectral information of the compound. The spectral function of the PDA detector makes it ideal for multi-residue analysis and compound validation. The new PDA detector achieves high sensitivity detection at high resolutions of 1.2 nm for high quality spectral information. These features not only make it useful for high sensitivity detection, but can also be used for spectral confirmation of compounds. In addition, multi-channel 2D chromatograms can be collected, which is extremely convenient for optimizing the detection wavelength of many different residual substances.
Researchers in Japan, Taiwan, and the United States use PDA detectors for multi-residue analysis or compound confirmation. The PDA detector not only obtains the ultraviolet spectrum of each tested substance, but also uses this spectrum to perform spectral comparison to confirm the target component, eliminate the false positive result, and optimize the ultraviolet detection wavelength of different residual substances. The residual substances detected include sulfa drugs, quinolones, nitrofurans, nicarbazin, clopyloprol, olaquindox, etc. in animal tissues, meat, aquatic products, eggs, and the like.
3.3 HPLC Reproducibility: Reliability of Residue Analysis The reproducibility of residue analysis requires long-term stable performance of the I-IPLC system. The innovative design of the HPLC system has a high flow rate accuracy of Zui, which gives us good retention time and peak area reproducibility. Accurate and accurate solvent mixing and overall optimization, Zui greatly reduces the variability of the HPLC process and distinguishes between subtle differences between samples.
3.4 Application of HPLC in residue detection â— Residues of nitrofurans in veterinary drug residues in animal foods (furazolidone, nitrofurazone, nitrofurantoin, furazolidone), sulfonamide residues (sulfonamide p-methoxypyrimidine, sulfamethazine) , sulfaquinoxaline), quinolones (chokequinoic acid, nalidixic acid) chlorohydroxypyridine, monensin and salinomycin, ethoxylated benzyl ester, chloramphenicol, ivermectin, clent Luo, nicarbazin, oxytetracycline, tetracycline, chlortetracycline (GB/T14931.1), amoxicillin, penicillin and olaquindox.
â— Pesticide residues, carbamate pesticides, organophosphorus pesticides, paraquat, herbicide, glyphosate and aminophosphonic acid, benzoxazole fungicides, 1 inuron, mosoon and enemies Diuron, triazine pesticides; rapid screening of 110 pesticides.
The multi-residue analysis of benzoxazole fungicide residues can also be carried out by HPLC. Some have used UV and fluorescence detection methods to analyze fungicides in grapes, beans, lettuce, strawberries and tomatoes, including thiabendazole (carbendazole), carbenclm~im, benomyl (benzamide), thiophanate-methyl. These compounds Uvzui absorb large amounts from 250 to 305 rim, of which thiabendazole (thiabendazole), carbendaz. Im, benomyl (benzaldehyde,) has natural fluorescence and can be analyzed by fluorescence detection.
Most organic phosphorus multi-residue analysis methods can use Gc as an analytical method, but Bmyan et al. used Uv detection technology to analyze a variety of pesticide residues in rice: including carbaryl (carbaryl), fenitrothion. The organophosphorus pesticides such as pirimiphos-methyl, chlorphfifos-methly, and methacrifos etrimfos can be extracted and purified using Sep-Pak Florisil cartridges. The method for rapid screening of pesticide residues is also detected by HPLC.
The pesticide method in the feed can also be analyzed by HPLC. Alan and Bushway developed a method for rapid analysis of multiple pesticides (rotenone rotenone, warfarin, carbaryl carbaryl, strychnine, or saponin) using a Waters instrument. Other pesticides in the feed may also be subjected to HPLC methods such as Thiamphenicol thiamphenicol, tetracycline and the like. Although this application is not included in the residual analysis, the corresponding method ideas can be used for reference.
HPLC chromatography is also suitable for residue analysis of the following types of samples, such as:
â— Biotoxins and other toxic and harmful residual substances - Toxins: aflatoxin, patulin;
â—Exogenous endocrine disrupting substances - hormones (diethylstilbestrol), polycyclic aromatic hydrocarbons, pentachlorophenol;
â— Analysis of transition metals (milk) and alkaline earth metals.
4 Liquid Chromatography and Mass Spectrometry : The Preferred Tool for Multi-Residue Analysis and Rapid Screening Methods Mass spectrometry detectors can detect a wide range of samples with high sensitivity and a wide range of structural information with a wide range of conventional HPLC detectors. However, although mass spectrometry often provides information on molecular ions and fragments of a compound, mass spectrometric analysis of mixtures is often difficult to achieve. Liquid chromatography coupled with mass spectrometry can first separate the mixture into a single component and then use a mass spectrometer for detection. Such a process can not only obtain more meaningful mass spectrometry data, but also can eliminate matrix interference to some extent, overcome ion suppression phenomena, and optimize mass spectrometry detection signals. The separation ability of HPLC and the rich information and high sensitivity of the mass spectrometer make the liquid chromatography-mass spectrometry using the mass spectrometer as the HPLC detection method become one of the rapid analysis methods of the current development.
The LC/MS system is the ideal detection method for residue analysis. For multi-residue rapid screening work requiring high sensitivity, wide application range and complex matrix, LC/MS is undoubtedly the preferred method for detection. To analyze the development of modern LC/MS technology, especially the development of conventional bench-top LC/MS systems, the mass spectrometer detector has played an increasingly important role in routine analysis as a high-sensitivity universal detector for HPLC.
The ZQ LC/MS system is a liquid-mass spectrometry system for atmospheric piezoelectric ionization (API). The system is equipped with the patented Zspmy connection 121, which has strong anti-pollution ability and high sensitivity (1.0 Pg reserpine signal-to-noise ratio 70:1), and the mass range can reach 40 (}0tm'lu. Easy to use The system and friendly interface make the system ideal for rapid screening, validation and quantitative analysis of residual materials. zQ LC/MS technology not only achieves extremely high sensitivity but also unique selectivity, and is suitable for many different sources and different Analysis of type samples. The design of the new ESCi source combines the characteristics of electrospray (EsI) and atmospheric pressure chemistry (APcI) sources. The mass spectrometry information of ESI+, ESI-, APCI+, and APCI- can be obtained simultaneously in one injection. It provides great convenience for rapid screening of a variety of residual substances.
Japan's Waters LC/MS laboratory has studied the rapid screening and confirmation analysis of various synthetic antibacterial agents in animal tissues, analysis of various pesticides in rice and grapefruit, trace analysis of carbamate pesticides and estrogens, etc.; Beijing laboratory has studied 22 kinds of veterinary drugs such as tetracycline, ampicillin and sulfonamide; the US LC/MS has also studied the analysis of veterinary drug residues such as clenbuterol, and cooperated with the US Environmental Protection Agency (EPA). LC/MS rapid screening analysis method for carbamate pesticides and their metabolites.
Key words: HPLC; SPE; liquid-mass spectrometry; veterinary drug residue; pesticide residue middle circle classification number 0657.63
The AppUcations of W aters SPE. HPLC and LC/MS Technology
On Residue Analysis in Food and Agro-preducts
Almract: The advantages of Waters products aRE introduced and the APPLicATION Waters SPE, HPLC and LC/MS technologes on residue analysis aIe described. The methods reviewed include extraction and analysis 0f veterinary drugs,pesticides,toxins and the other harmful residues in a variety 0f sample matrixes. The multiresidue technique is also discussed.
Key words: HPLC; SPE; LV/MS; rescues veterinary drugs; rescues pesticides.
1 Introduction Residue monitoring, as an important issue in food safety, requires the use of multiple sample preparation methods and analytical testing methods. The continuous development of high performance liquid chromatography and liquid chromatography- mass spectrometry has made it more and more widely used in the detection and analysis of toxic and hazardous substances of different types of veterinary drugs, pesticides and toxins. Unlike other liquid chromatography applications, residue analysis for food and agricultural products places high demands on sensitivity, reproducibility, and selectivity, often requiring the detection of trace amounts of residual material at ppb or lower levels in complex matrices. . If you want to achieve the above goals, you may not only need good sample preparation methods to purify complex food and agricultural products, concentrate target components, but also need to select high-performance, high-sensitivity HPLC or LC/MS systems for detection and analysis.
This paper will discuss the analysis of pesticides, veterinary drug residues, biotoxins and other toxic and harmful residues in food, feed and agricultural products from the aspects of solid phase extraction technology, HPLC and LC/MS technology.
2 Solid phase extraction technology for sample preparation High-efficiency extraction and purification of food and agricultural product samples to improve detection selectivity and sensitivity. Samples must be pre-treated regardless of LC, GC , LC/MS and slave instruments. Among many methods, solid phase extraction technology is one of the technologies that have developed zui in recent years and has become more and more widely used. Solid phase extraction (SPE) is a sample preparation technique based on the principle of liquid chromatography, using solid chromatography cartridges to purify the sample background or extract the target components in the solution. Compared with liquid-liquid extraction technology, SPE technology is easy to operate, high in extraction efficiency, low in solvent consumption, easy to automate, and easier to obtain high recovery results.
In 1978, Waters first commercialized SPE technology. The trademark of solid phase extraction product named sep-Pak was registered. Since then, Sep-Pak solid phase extraction technology has been widely used.
SPE technology solid phase extraction fillers are reversed, normal phase, ion exchange and other types, including Cl8, C8, C2, -NH2, -Diol, -CN, Silica, Flofisil, alumina, polymer matrix, anion / cation Exchange and a variety of adsorbents such as DNPH. In 1996, a new universal filler Oasis HLB and a dual-mechanical filler with high selectivity (such as OasisMCX/MAX- with both ion exchange and reversed-phase mechanisms) were introduced, which can be used for acidic, basic and neutral organic compounds. Extraction, as well as high selectivity of acidic or basic compounds, are separately extracted. The introduction of the new Oasis filler further expands the application of SPE technology and establishes new standards for SPE technology recovery, reproducibility and versatility.
In the detection of food and agricultural products and feed residues, SPE is used several times to achieve sample purification and target component enrichment. Antibiotics in meat (such as tetracyclines, chloramphenicol, etc.), sulfa drugs, quinolones, hormones (such as diethylstilbestrol), clenbuterol, furazolidone, nitrofurazone and other veterinary drugs; carbamate, organic phosphorus and other pesticides Aflatoxin, patulin and other toxins can be extracted by SPE means multi-residue analysis or matrix pre-dispersion extraction (MatrkSolid Phase Dispersion Extraction) and gel permeation chromatography (GPc) for sample preparation .
3 Liquid Chromatography: An important tool for residue detection HPLC can be used for the analysis of difficult to volatile, more polar substances. It is estimated that the GC method can only solve about 20% of organic matter analysis, and about 80% of organic matter can be analyzed by HPLC method. The characteristics of veterinary drugs make it generally suitable for HPLC analysis; many methods of pesticide residue analysis also use HPLC method. Unlike other conventional HPLC applications, residue analysis requires high sensitivity and reproducibility. High sensitivity can achieve good results for trace target components in complex matrices; high reproducibility is the basic guarantee for high confidence levels. To achieve the above objectives, an HPLC system needs to be optimized.
3.1 Sensitivity: Necessary conditions for residue analysis The sensitivity of chromatographic results is usually measured by the ratio of signal to noise (ie, signal-to-noise ratio). Therefore, the sensitivity can be improved by increasing the response value of the detection signal or reducing the noise. For HPLC systems, the increase in signal strength is primarily due to the performance of the detector.
The UV absorption characteristics of most substances make the UV detector a universal HPLC detector commonly used in multi-residue analysis. It is often used to quickly screen a variety of veterinary drugs or pesticide residues. Such as sulfa drug residues, tetracycline residues, furazolidone, chloramphenicol, tetracycline and so on. The dual-channel UV detector with patented trapezoidal slit cell design fully absorbs the energy of the xenon lamp and achieves highly sensitive detection results.
Fluorescence detectors with high sensitivity and selectivity are effective tools for residue analysis. * A carbamate AOAC method for multi-residue analysis uses an analytical method for post-column derivatization. Zui newly developed multi-wavelength fluorescence detector, unique axial illumination flow cell design, zui greatly reduced light scattering, effectively lengthening the length of the cell; the new xenon lamp used in the detector can also emit higher light energy The above optimized design provides unmatched high sensitivity fluorescence detection for low concentration samples.
Since most compounds do not have a natural fluorescence response, many methods using fluorescence detectors require post-column derivatization to produce or enhance the fluorescence response characteristics of the target component for high sensitivity detection. Using a HPLC system optimized for carbamate analysis, 11 carbamates and their metabolites can be analyzed simultaneously. The system can be used not only for high-sensitivity detection of carbamate residue residues, but also for a variety of residue analyses that require post-column derivatization-fluorescence detection or without the need to derivatize natural fluorescent materials. Woell et al. used post-column derivatization of this system. Fluorescence detection methods successfully analyzed some residues of glyphosate and its metabolites in vegetables, fruits, grains and water.
Trace analysis of aflatoxin in cereals, peanuts and other matrices can also be performed using the above system. Detector-optimized systems can easily reach the ppt level of detection.
3.2 Multi-residue analysis and compound confirmation: Making full use of the spectral function of the photodiode matrix detector Photodiode matrix detector (PDA) as one of the UV detectors can not only obtain the chromatographic information, but also obtain the real-time spectral information of the compound. The spectral function of the PDA detector makes it ideal for multi-residue analysis and compound validation. The new PDA detector achieves high sensitivity detection at high resolutions of 1.2 nm for high quality spectral information. These features not only make it useful for high sensitivity detection, but can also be used for spectral confirmation of compounds. In addition, multi-channel 2D chromatograms can be collected, which is extremely convenient for optimizing the detection wavelength of many different residual substances.
Researchers in Japan, Taiwan, and the United States use PDA detectors for multi-residue analysis or compound confirmation. The PDA detector not only obtains the ultraviolet spectrum of each tested substance, but also uses this spectrum to perform spectral comparison to confirm the target component, eliminate the false positive result, and optimize the ultraviolet detection wavelength of different residual substances. The residual substances detected include sulfa drugs, quinolones, nitrofurans, nicarbazin, clopyloprol, olaquindox, etc. in animal tissues, meat, aquatic products, eggs, and the like.
3.3 HPLC Reproducibility: Reliability of Residue Analysis The reproducibility of residue analysis requires long-term stable performance of the I-IPLC system. The innovative design of the HPLC system has a high flow rate accuracy of Zui, which gives us good retention time and peak area reproducibility. Accurate and accurate solvent mixing and overall optimization, Zui greatly reduces the variability of the HPLC process and distinguishes between subtle differences between samples.
3.4 Application of HPLC in residue detection â— Residues of nitrofurans in veterinary drug residues in animal foods (furazolidone, nitrofurazone, nitrofurantoin, furazolidone), sulfonamide residues (sulfonamide p-methoxypyrimidine, sulfamethazine) , sulfaquinoxaline), quinolones (chokequinoic acid, nalidixic acid) chlorohydroxypyridine, monensin and salinomycin, ethoxylated benzyl ester, chloramphenicol, ivermectin, clent Luo, nicarbazin, oxytetracycline, tetracycline, chlortetracycline (GB/T14931.1), amoxicillin, penicillin and olaquindox.
â— Pesticide residues, carbamate pesticides, organophosphorus pesticides, paraquat, herbicide, glyphosate and aminophosphonic acid, benzoxazole fungicides, 1 inuron, mosoon and enemies Diuron, triazine pesticides; rapid screening of 110 pesticides.
The multi-residue analysis of benzoxazole fungicide residues can also be carried out by HPLC. Some have used UV and fluorescence detection methods to analyze fungicides in grapes, beans, lettuce, strawberries and tomatoes, including thiabendazole (carbendazole), carbenclm~im, benomyl (benzamide), thiophanate-methyl. These compounds Uvzui absorb large amounts from 250 to 305 rim, of which thiabendazole (thiabendazole), carbendaz. Im, benomyl (benzaldehyde,) has natural fluorescence and can be analyzed by fluorescence detection.
Most organic phosphorus multi-residue analysis methods can use Gc as an analytical method, but Bmyan et al. used Uv detection technology to analyze a variety of pesticide residues in rice: including carbaryl (carbaryl), fenitrothion. The organophosphorus pesticides such as pirimiphos-methyl, chlorphfifos-methly, and methacrifos etrimfos can be extracted and purified using Sep-Pak Florisil cartridges. The method for rapid screening of pesticide residues is also detected by HPLC.
The pesticide method in the feed can also be analyzed by HPLC. Alan and Bushway developed a method for rapid analysis of multiple pesticides (rotenone rotenone, warfarin, carbaryl carbaryl, strychnine, or saponin) using a Waters instrument. Other pesticides in the feed may also be subjected to HPLC methods such as Thiamphenicol thiamphenicol, tetracycline and the like. Although this application is not included in the residual analysis, the corresponding method ideas can be used for reference.
HPLC chromatography is also suitable for residue analysis of the following types of samples, such as:
â— Biotoxins and other toxic and harmful residual substances - Toxins: aflatoxin, patulin;
â—Exogenous endocrine disrupting substances - hormones (diethylstilbestrol), polycyclic aromatic hydrocarbons, pentachlorophenol;
â— Analysis of transition metals (milk) and alkaline earth metals.
4 Liquid Chromatography and Mass Spectrometry : The Preferred Tool for Multi-Residue Analysis and Rapid Screening Methods Mass spectrometry detectors can detect a wide range of samples with high sensitivity and a wide range of structural information with a wide range of conventional HPLC detectors. However, although mass spectrometry often provides information on molecular ions and fragments of a compound, mass spectrometric analysis of mixtures is often difficult to achieve. Liquid chromatography coupled with mass spectrometry can first separate the mixture into a single component and then use a mass spectrometer for detection. Such a process can not only obtain more meaningful mass spectrometry data, but also can eliminate matrix interference to some extent, overcome ion suppression phenomena, and optimize mass spectrometry detection signals. The separation ability of HPLC and the rich information and high sensitivity of the mass spectrometer make the liquid chromatography-mass spectrometry using the mass spectrometer as the HPLC detection method become one of the rapid analysis methods of the current development.
The LC/MS system is the ideal detection method for residue analysis. For multi-residue rapid screening work requiring high sensitivity, wide application range and complex matrix, LC/MS is undoubtedly the preferred method for detection. To analyze the development of modern LC/MS technology, especially the development of conventional bench-top LC/MS systems, the mass spectrometer detector has played an increasingly important role in routine analysis as a high-sensitivity universal detector for HPLC.
The ZQ LC/MS system is a liquid-mass spectrometry system for atmospheric piezoelectric ionization (API). The system is equipped with the patented Zspmy connection 121, which has strong anti-pollution ability and high sensitivity (1.0 Pg reserpine signal-to-noise ratio 70:1), and the mass range can reach 40 (}0tm'lu. Easy to use The system and friendly interface make the system ideal for rapid screening, validation and quantitative analysis of residual materials. zQ LC/MS technology not only achieves extremely high sensitivity but also unique selectivity, and is suitable for many different sources and different Analysis of type samples. The design of the new ESCi source combines the characteristics of electrospray (EsI) and atmospheric pressure chemistry (APcI) sources. The mass spectrometry information of ESI+, ESI-, APCI+, and APCI- can be obtained simultaneously in one injection. It provides great convenience for rapid screening of a variety of residual substances.
Japan's Waters LC/MS laboratory has studied the rapid screening and confirmation analysis of various synthetic antibacterial agents in animal tissues, analysis of various pesticides in rice and grapefruit, trace analysis of carbamate pesticides and estrogens, etc.; Beijing laboratory has studied 22 kinds of veterinary drugs such as tetracycline, ampicillin and sulfonamide; the US LC/MS has also studied the analysis of veterinary drug residues such as clenbuterol, and cooperated with the US Environmental Protection Agency (EPA). LC/MS rapid screening analysis method for carbamate pesticides and their metabolites.
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