And its application in the analysis of toxic and hazardous substances residues in veterinary drugs, pesticides and toxins in food and agricultural products.
1. Introduction Abstract: Discuss liquid chromatography related technologies and their applications in residue analysis. A solid phase extraction technique for sample preparation (SPE liquid chromatography (HPLC LC/MS) (LCMS features) was introduced.
A variety of pre-sample disposal methods and analytical testing methods are required. From time to time, high performance liquid chromatography and LC/MS technology, residue monitoring is an important issue in food safety. It is more and more widely used in the detection and analysis of toxic and harmful substances of different types of veterinary drugs, pesticides and toxins. Residue analysis of foods and agricultural products that differ from other liquid chromatography applications requires very high sensitivity, reproducibility, and selectivity, often requiring the detection of trace amounts of residual material at ppb levels or even lower levels in complex matrices. If you want to achieve the above goals, you may not only need good pre-sample disposal methods to purify complex food and agricultural products, concentrate target components, but also need high-performance, high-sensitivity HPLC or LCMS systems for detection and analysis.
In this paper, the analysis of pesticides, veterinary drug residues, biotoxins and other toxic and harmful residues in food, feed and agricultural products will be discussed from the aspects of sample pretreatment solid phase extraction technology, high performance liquid chromatography and LCMS technology.
2. Solid phase extraction technology for sample pretreatment
Improve detection selectivity and sensitivity Efficient extraction and purification of food and agricultural product samples using LCGCLCMS and from instrumental methods. Samples must be pretreated. Among the 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 technology (SPE based on the principle of liquid chromatography, using solid chromatography cartridges to purify the sample background or sample pretreatment technology in the extraction solution. Compared with liquid-liquid extraction technology, SPE technology is easy to operate and high extraction efficiency Low solvent consumption, easy automation, and easier to achieve high recovery results.
For the first time, Water has pushed SPE technology to commercialization. And registered a trademark called sep-Pak solid phase extraction product, 1978. Later, Sep-Pak solid phase extraction technology has been widely used.
There are Cl8C8C2-NH2-Diol-CNSilicaFlofisil alumina, SPE technology solid phase extraction filler has many types such as reverse phase, normal phase and ion exchange. Polymer matrix, anion/cation exchange and DNPH and other adsorbents. In 1996, a new universal filler OasisHLB and a dual-mechanical filler with high selectivity (such as OasisMCXMAX-with both ion exchange and reversed-phase mechanisms) were introduced for simultaneous extraction of acidic, basic and neutral organic compounds, and acidity. Or the high selectivity of the basic compounds are separately extracted. The introduction of the new Oasi filler further expands the application field of SPE technology and establishes new standards for SPE technology recovery, reproducibility and versatility.
SPE is used for sample purification and target component enrichment. Antibiotics (such as tetracyclines, chloramphenicol, etc.) sulfa drugs, quinolones, hormones (such as diethylstilbestrol), clenbuterol, furazolidone, Veterinary drugs such as nitrofurazone; pesticides such as carbamate and organophosphorus; toxins such as aflatoxin and patulin can be extracted by SPE, multi-residue analysis and matrix solid phase dispersion extraction (MatrkSolidPhaseDispersionExtract technology and gel permeation) Chromatography method (GPc for sample preparation. Food and agricultural products and feed residue testing.
The GC method can only solve about 20% organic matter analysis, 3. Liquid chromatography technology: an important tool for residue detection HPLC can be used for the analysis of difficult to volatile, more polar substances. It is estimated. About 80% of the 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. Residue analysis that differs from other conventional HPLC applications 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. The HPLC system needs to be optimized to achieve the above objectives.
Regardless of the response of the detection signal, 3.1 sensitivities: the necessary conditions for residual analysis. The sensitivity of the chromatographic results is usually measured by the ratio of signal to noise (ie, signal-to-noise ratio). therefore. Or to reduce the noise can achieve the purpose of improving sensitivity For the HPLC system, the improvement of signal strength is mainly due to the performance of the detector.
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. The UV absorption characteristics of most materials make the UV detector a universal HPLC detector commonly used in multi-residue analysis. High sensitivity results can be obtained.
The unique axial illumination flow cell design with high sensitivity and selectivity of the fluorescence detector is an effective tool for residue analysis. * A carbamate AOAC method for multi-residue analysis uses an analytical method for post-column derivatization. Zui has developed a multi-wavelength fluorescence detector. Zui greatly reduces light scattering and effectively lengthens the length of the cell; the new xenon lamp used in the detector can also emit higher light energy. The above optimized design can provide unmatched high sensitivity fluorescence detection for low concentration samples. .
Many methods using fluorescence detectors require post-column derivatization to effect or enhance fluorescence response characteristics of the target component, since most compounds do not have a natural fluorescence response. For the purpose of high sensitivity detection, an HPLC system optimized for carbamate analysis can simultaneously analyze 11 carbamates and their metabolites. The system can be used not only for high-sensitivity detection of carbamate residual pesticide 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. The fluorescence detection method successfully analyzed the 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.
Not only can chromatographic information be obtained, 3.2 multi-residue analysis and compound confirmation: full use of the photodiode matrix detector of the photodiode matrix detector (PDA as one of the UV detectors) and real-time spectral information of the compound can be obtained. The detector's spectral function makes it ideal for multi-residue analysis and compound validation. The new PDA detector provides high-sensitivity detection at high resolutions of 1.2 nm for high-quality spectral information. These features not only make it useful High sensitivity detection, and can be used for spectral confirmation of compounds. In addition, multi-channel 2D chromatograms can be collected, which is very convenient for optimizing the detection wavelength of many different residual substances.
Spectra comparisons can be performed with this spectrum to confirm target components. Researchers in Japan, Taiwan, and the United States use PDA detectors for multi-residue analysis or compound confirmation. The PDA detector is used to obtain not only the ultraviolet spectrum of each test substance. The false positive results were excluded and the UV detection wavelength of the different residual materials was optimized. The residual substances detected include sulfa drugs, quinolones, nitrofurans, nicarbazin, clopidol (clopido1 olaquindox), etc. in animal tissues, meat, aquatic products, eggs, and the like.
The reserving time and peak area reproducibility of Zui Jia can be obtained. Accurate and accurate solvent mixing and overall optimization, 3.3 HPLC reproducibility: Reliable analysis of residue analysis Reproducibility of residue analysis requires temporary stability of the I-IPLC system. The innovatively designed HPLC system features high flow accuracy. Zui greatly reduces the variability of the HPLC process and is able to distinguish subtle differences between samples.
3.4 Application in HPLC residue detection
Veterinary drug residue
Nitrofuran residues in animal-derived foods (furazolidone, nitrofurazone, nitrofurantoin, furazolidone) sulfonamide residues (sulfonamide p-methoxypyrimidine, sulfamethazine, sulfaquinoxaline) quinolones (chokequinic acid, naphthalene Citric acid) chlorohydroxypyridine, monensin and salinomycin, ethoxy benzyl benzyl ester, chloramphenicol, ivermectin, clenbuterol, nicarbazin, oxytetracycline, tetracycline, chlortetracycline (National standard GBT14931.1 amoxicillin, penicillin and olaquindox.
Pesticide residue
Carbamate pesticides, organophosphorus pesticides, paraquat, herbicide fast, glyphosate and aminophosphonic acid, benzoxazole fungicides, Ligulong (1inuron chlorpyrifos mosuron and diuron triazine) Class pesticides; rapid screening of 110 pesticides.
Multi-residue analysis including thiabendazol thiabendazole) carbenclm~imbenomyl benomyl and benzoxazole fungicide residues can also be performed by HPLC. Some people have used UV and fluorescence detection methods to analyze fungicides in grapes, beans, lettuce, strawberries and tomatoes. Thiophanate-methyl these compounds Uvzui large absorption in 250305rim where thiabendazol thiabendazole) carbendaz. Imbenomyl benomyl, with natural fluorescence, can be analyzed by fluorescence detection.
However, Bmyan et al. used Uv detection technology to analyze a variety of pesticide residues in rice: including carbaryl carbaryl fenitrothionpirimiphos-methylchlorphfifos-methlimethacrifosetrimfo. These organophosphorus pesticides can be extracted and purified using Sep-PakFlorisil cartridges. The method for rapid screening of pesticide residues is also detected by HPLC. Most organophosphorus multi-residue analysis methods can use Gc as an analytical tool.
Warfarin, the pesticide in the feed can also be analyzed by HPLC. Alan and Bushwai developed a method for rapid analysis of multiple pesticides (rotenon rotenone, carbaryl carbaryl, strychnin, or saponin) using a Water 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.
For example: HPLC chromatography is also suitable for residue analysis of the following types of samples.
Biotoxins and other toxic and harmful residual substances - toxins: aflatoxin, patulin;
Exogenous endocrine disrupting substances - hormones (diethylstilbestrol) polycyclic aromatic hydrocarbons, pentachlorophenol;
Analysis of transition metals (in milk) and alkaline earth metals.
High sensitivity, 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. A large variety of structural information can be obtained with different and 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. This process can not only obtain more meaningful mass spectrometry data, but also eliminate matrix interference at a certain level, overcome ion suppression phenomena, and optimize mass spectrometry detection signals. The HPLC separation ability 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.
Liquid-mass spectrometry is undoubtedly the preferred means of detection. To analyze the development of modern liquid chromatography-mass spectrometry, the LC/MS system is an ideal detection method for residue analysis. For multi-residue rapid screening jobs that require high sensitivity, wide range of application, and complex matrices. In particular, the development of the conventional benchtop LC/MS system has made the mass spectrometer more and more important in the routine analysis as a high-sensitivity universal detector for HPLC.
The system is well suited for rapid screening, validation and quantitative analysis of residual materials. zQ LC/MS technology can not only obtain extremely high sensitivity and unique selectivity, ZQLCMS system is atmospheric piezoelectric ion source (API liquid chromatography system. The system is equipped with patented Zspmy connection 121 has strong anti-pollution ability and high Sensitivity (1.0Pg reserpine signal-to-noise ratio 701 mass range up to 40}0tm'lu easy-to-use system and friendly operation interface. Also suitable for analysis of many different sources and different types of samples. Design of new ESCi source Electrospray (EsI and atmospheric pressure chemistry (APcI source features are integrated, and ESI+ESI-APcI+ and APCI-MS information can be obtained simultaneously in one injection, which provides great convenience for rapid screening of various residual substances.
It also cooperated with the US Environmental Protection Agency (EPA) to develop LCMS rapid screening analysis method for carbamate pesticides and their metabolites. The Japanese Water Liquid Mass Spectrometry Laboratory has studied the rapid screening and confirmation analysis of various synthetic antibacterial agents in animal tissues. , a variety of pesticide analysis in rice and grapefruit, trace analysis of carbamate pesticides and estrogen; Water Beijing laboratory studied 22 kinds of veterinary drugs such as tetracycline, ampicillin, sulfonamide, etc.; The laboratory also studied the analysis of veterinary drug residues such as clenbuterol.
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