Jiang Shiqiang: Food Safety Demand for Scientific Instruments for Inspection and Testing

Original topic: Demand for scientific instruments and equipment for inspection and testing in the establishment of a food safety assurance system

Note: This article was serialized in the 4th, 5th and 6th issues of the 2009 Food Safety Guide

(Chinese Society of Instrumentation and Instrument, Beijing 100101, Chinese Academy of Agricultural Sciences, Beijing 100081, Chinese Analysis and Testing Association, Beijing 100045)

Among the many public safety issues, food safety is of most concern to the world. China also attaches great importance to the establishment of a food safety assurance system. It has formulated a series of related laws, regulations and standards, and adopted a series of major measures. It was promulgated and implemented in November 2006. The “Law of the People ’s Republic of China on the Quality and Safety of Agricultural Products” has implemented the “Law of the People ’s Republic of China on Food Safety” on June 1, 2009. As we all know, a complete food safety guarantee system should be reflected in: (1) sound laws, regulations and standards; (2) complete systems and institutions; (3) advanced testing equipment and technology; (4) producers ’self-discipline on food safety Strong sense; (5) Monitoring and supervision are timely and powerful. Eventually to ensure food safety. Among them, the technical support is scientific instruments and equipment for inspection, detection and monitoring. It runs through food safety risk monitoring and evaluation, implementation of safety standards, detection in all links, analysis and handling of accidents, daily supervision and supervision.

1. The demand for scientific instruments and equipment for different detection, inspection and monitoring targets

The harmful, toxic and suspicious substances closely related to food safety are: residues of pesticides and veterinary drugs and other harmful compounds, toxic and harmful elements, pathogenic bacteria, genetically modified products, etc., which are now summarized one by one as follows.

1.1 Instruments for detecting pesticide residues

Pesticide residues can be divided according to chemical composition and structure, and are now described as follows according to the suitability of the required analytical instruments.

1.1.1 Organochlorine pesticide residue testing equipment

Widely used GC-ECD equipped with electron capture detector, has the advantages of high sensitivity, high separation, accurate quantitative and so on. When the matrix or composition is more complex, it is difficult to characterize based on the GC retention time, you need to use a mass spectrometer detector, with the help of the selected ion detection (SIM) mode for qualitative, that is, using gas-mass spectrometry (GC-MS) or even GC -MS-MS instrument.

1.1.2 Instruments for organophosphorus pesticide residue detection

It is widely used with gas chromatograph equipped with flame photometric detector (FPD) or nitrogen phosphorus detector (NPD) and ECD, and is accurately characterized by GC-MS. For high-boiling or thermally unstable organophosphorus pesticide residues, a liquid chromatograph (HPLC-UV) equipped with an ultraviolet-visible light detector should be used. The AOAC standard method for organophosphorus pesticide residue detection in the United States uses HPLC. In recent years, liquid-mass spectrometry (LC-MS) has also been used to carry out organic phosphorus multi-residue analysis.

1.1.3 Apparatus for carbamate pesticide residue detection

For carbamate pesticide residues with high thermal stability, it can be detected by gas chromatography (GC-FID / NPD / ECD), but most carbamate pesticides have poor thermal stability, so post-column derivatization is widely used, with fluorescence Liquid Chromatograph (HPLC-FLD) of the detector. For samples with complex matrices, HPLC peak separation has many difficulties, so in recent years, liquid-mass spectrometry (LC-MS) has been used as the preferred method.

1.1.4 Pyrethroid pesticide residue detection equipment

GC-ECD is widely used, and HPLC-UV is also used, and confirmed by GC-MS.

1.1.5 Herbicide pesticide residue detection equipment

Widely used GC-ECD or GC-NPD, commonly used HPLC to make up for the deficiencies of GC, confirmed by HPLC-MS and GC-MS-MS equipped with APCL source.

In summary, the pesticide residue detection instrument is mainly a GC equipped with various detectors, supplemented by HPLC, and is generally characterized and confirmed by GC-MS. When the matrix is ​​complex, use LC-MS or even GC-MS-MS to confirm.

Nowadays, pesticide multiresidue detection is highly valued by developed countries in the world. In 2006, China released 8 national standards for 651 pesticide multiresidue detection methods in plant-derived foods. The sample preparation techniques used vary, but the instruments used are all GC-MS or LC-MS-MS.

1.2 Instruments for detecting residues of veterinary drugs and fishery drugs

Veterinary medicine and fishery medicine can be roughly divided into 15 categories, the detection methods and instruments are described as follows

1.2.1 Apparatus for detecting β-lactam antibiotic residues

Most of them use HPLC, and the confirmation of the residues relies on LC-MS and LC-MS-MS, replacing the GC-MS instruments and methods that have been used in the past.

1.2.2 Apparatus for detecting residues of aminoglycoside antibiotics

Except that gentamicin can be detected by GC-ECD instrument, most of the detection of this kind of antibiotic residue depends on HPLC-FLD. LC-MS-MS is mainly used for the confirmation of antibiotic residues in milk samples.

1.2.3 Instruments for detecting macrolide antibiotic residues

Used TLC and GC, it has been replaced by HPLC today. Some can be tested and confirmed by GC-MS, but most of them need to be checked and confirmed by LC-MS-MS.

1.2.4 Instruments for detecting residues of tetracycline antibiotics

The cup and saucer method is accurate and economical, but the structure cannot be distinguished, so today the cup and saucer are used to screen out positive samples, and then confirmed by HPLC and LC-MS-MS.

1.2.5 Apparatus for detecting residues of aminobenzyl antibiotics

Available GC-ECD and microplate reader (ELISA) detection. Confirmed by GC-MS (NCI) GC-MS-MS, HPLC-MS-MS.

1.2.6 Instruments for detecting sulfonamide residues

It can be screened by microbial inhibition method, and detected with a microplate reader and a kit, but the most used are HPLC-UV / FID, GC-MS, HPLC-MS and HPLC-MS-MS

1.2.7 Instruments for detecting quinolone residues

Although TLC instrument, fluorescence spectrometer (FID) and GC-MS instrument have been used, HPLC-FID / UV, HPLC-MS and HPLC-MS-MS instruments are generally used for qualitative and quantitative analysis.

1.2.8 Instruments for detecting nitroimidazole residues

Although it can be detected by GC-NPD and GC-MS (NCI), most of them still rely on HPLC-UV and HPLC-MS-MS for detection and confirmation.

1.2.9 Instruments for detecting nitrofuran residues

In the past, the HPLC-UV instrument was used for detection. Because the sensitivity is not high and it cannot be characterized, it has now been changed to HPLC-MS and HPLC-MS-MS.

1.2.10 Apparatus for detecting residues of hormones and other growth promoters

It can be detected by HPLC-UV, but the sensitivity is low. Today, GC-MS and GC-MS-MS have been used, and further transition to HPLC-MS, or even HPLC-MS-MS.

1.2.11 Instruments for detecting thyroid inhibitor residues

Commonly used HPLC and TLC, and further transition to adopt GC-MS and HPLC-MS.

1.2.12 Apparatus for detecting residual β-agonist

Commonly used HPLC-UV / FLD / PAD / electrochemical detectors, GC-MS, capillary electrophoresis (CE), HPLC-MS and HPLC-MS-MS can also be used.

1.2.13 Instruments for detecting residues of insect repellent

Mainly rely on HPLC-UV / FLD and HPLC-MS and HPLC-MS-MS.

1.2.14 Instruments for detecting sedative residues

There are many instruments available, including HPLC, GC, TLC, GC-MS and HPLC-MS, and ELISA.

1.2.15 Instruments for detecting dye residues

UV, GC-MS, HPLC and HPLC-MS-MS can be used.

Veterinary drug multi-residue detection has received great attention internationally in recent years. In 2006, China issued 25 national standards for 118 animal veterinary drug residue detection methods in animal-derived foods, of which 18 are multi-residue analysis methods, all using LC-MS -MS.

In summary, referring to the national standards of AOAC, CAC, EU, Japan and China, it is clear that the instruments and equipment for the detection of veterinary drug residues are higher than the instruments for pesticide residues detection. The main manufacturers of the above chromatographs and color / mass spectrometers:

(a) Foreign manufacturers of GC, GC-MS, GC-MS-MS include Agilent, Shimazu, Thermo, Perkinelmer, Varian, etc .; major domestic manufacturers include Beijing Dongxi Electronics, Shanghai Jingke, Tianmei and Beifen But there is no domestic product of GC-MS-MS.

(b) Foreign manufacturers of HPLC, HPLC-MS, HPLC-MS-MS include waters, Thermo, ABI, Agilent, Shimazu, Perkelmer, Dionex, Varian, etc .; only HPLC can be produced in China. Branch, Shanghai Jingke, Wufeng, Zhejiang Wenling, Dalian Elite, etc.

1.3 Instruments for detecting toxic and harmful elements and their valence analysis

The most classic is the use of atomic absorption spectrometry (AAS), coupled with flame and graphite furnace, which can detect trace levels of elements. Atomic fluorescence spectrometer (AFS) with independent intellectual property rights in China can be used to detect arsenic, lead, mercury, tin, selenium, germanium, antimony and other elements, with high sensitivity, low detection limit, simultaneous detection of multiple elements, and low price . In recent years, inductively coupled plasma emission spectroscopy-mass spectrometry (ICP-MS) has attracted attention for its high sensitivity and detection limit of ng / ml level.

In view of the different valence (morphology) of the same element and the great difference in toxicity, the detection of element valence has attracted much attention in recent years. HPLC-AAS, GC-AAS, HPLC-ICP-MS and CE-ICP- MS instrument, the latter two combined technologies and instruments are quite perfect, but the price is very expensive. In recent years, the LC-AFS combination instrument that has been successfully developed in China and has been mass-produced has sensitivity and detection limits that can meet the requirements of agricultural products and food safety testing. It is also inexpensive and suitable for selection by agricultural product quality inspection centers and stations.

The above instrument manufacturers:

(a) AAS, the main foreign manufacturers are: Thermo, perkinElemer, Shimazu, Varian, jena AG, etc. There are Beijing General Analysis, Dongxi Electronics, Rayleigh, Shanghai Jingke, Spectrum, Tianmei and so on.

(b) The main foreign manufacturers of Icp and Icp-MS are: Thermo, perkinElemer, Shimazu, Agilent, Varian, etc .; there are no domestic mass production manufacturers.

(c) AFS is currently only produced in China. The famous manufacturers are Beijing Jitian, Haiguang, Rayleigh, etc., among which Jitian also produces LC-AFS element valence detectors.

1.4 Apparatus for pathogenic bacteria inspection and bacterial identification

According to statistics, more than 31% of foodborne disease outbreaks are caused by microorganisms (pathogenic bacteria), so the detection of pathogenic bacteria should be fully paid attention to in the detection of agricultural products and food safety. So far, there are three major types of methods for bacterial identification and pathogenic bacteria testing: traditional methods, numerical methods based on traditional methods, chemical and molecular biology methods, and each method derives several methods and testing instruments. Traditional methods have been used in China in the past, that is, after cultivating the samples with bacteria, the bacteria were analyzed and detected according to the microscopic examination of the morphological characteristics of the bacteria. In recent years, a large number of new methods and instruments have been widely used abroad.

(1) Automatic identification and inspection of the metabolic utilization rate of different carbon sources by different bacteria, which belongs to numerical methods and instruments, such as API, ATB, VITEK and other systems.

(2) Utilize the specific binding reaction between antigen and antibody for immunoreaction analysis and pathogenic bacteria test, of which enzyme-linked fluorescence immunoassay (ELFIA) is represented, such as VIDAS system.

(3) Use gene detection technology to detect pathogens and identify bacteria, such as DuPont's BAX system and RP (Ridopvinter) system for strain identification, typing and traceability.

(4) Pathogen detection system based on surface plasmon resonance (SPR) biosensor, such as Biacore system.

(5) Based on the biochip technology platform, pathogenic bacteria detection kits are used to detect pathogenic bacteria. For example, China Biotech has developed a biochip detection system that can detect 12 food-borne pathogenic bacteria.

(6) Bacterial identification based on the characteristic fatty acid profile of different bacteria, such as the system developed by Agilent.

The manufacturers of pathogenic bacteria inspection and automatic bacteria identification systems are: Biomerieux, Dupont, Biologe, Agilent, GE Heailhcare, etc .; in the past, only the inhibitory zone analyzer and colony counter can be produced in China. In recent years, Boao and other manufacturers have also appeared. Can produce pathogenic bacteria detection system.

1.5 Genetically modified agricultural products testing instruments

The detection of genetically modified agricultural products is to detect the presence of foreign genes in agricultural products. In essence, it is to detect promoters, terminators, marker gene fragments, target gene fragments, and the abundance of foreign gene transcription products. In terms of methods, it is divided into gene-level detection (various PCR qualitative and quantitative methods and gene chip technology) and gene transcription level detection (enzyme-linked immunosorbent reaction technology, protein chip technology and Southen hybrid Western blotting, etc.), mainly The instrument is divided into 3 parts according to the test procedure:

(1) Instruments and equipment for DNA sample preparation: kits, centrifuges, oscillators, etc .;

(2) Instruments and equipment for gene amplification: PCR instrument, mixed solution, fidelity DNA polymerase, etc .;

(3) Equipment for separation, analysis and verification: electrophoresis system, imaging analysis system, nucleic acid (protein) analyzer, microplate reader, plate washer, quantitative PCR instrument, etc.

The major foreign manufacturers of these instruments and equipments are BI0-RAD, Thermo-Life Sciences, GE, etc .; although there are no domestic manufacturers that produce the above instruments completely, Shanghai Tianneng, Tianmei, Sanke, Xinzhi, Hangzhou Langji, Bori , Beijing, Liuyi, etc. each produce some of the above instruments.

1.6 Instruments for testing the quality and nutritional composition of agricultural products

In addition to the quality testing equipment required by each individual, various agricultural, animal husbandry, and fishery products are generally universal quality and nutrition testing equipment. There are:

(1) Kjeldahl nitrogen / protein analyzer, Dumas nitrogen / protein analyzer and protein analyzer;

(2) Fat tester and fatty acid tester (gas chromatograph);

(3) Cellulose tester;

(4) Milk and juice detectors;

(5) Sugar (sugar content) detector;

(6) Near-infrared agricultural product quality analyzer;

(7) Rapid detectors for agricultural products and foods (determination of nitrate, formaldehyde, white block, sulfur dioxide, peroxide value, etc.);

(8) Amino acid analyzer;

(9) Vitamin tester (liquid chromatography);

(10) Trace element analyzer (atomic absorption spectrometer).

The main foreign manufacturers are: Flowserve, Butch, Brook, etc. In recent years, some domestic manufacturers have appeared: Fiber Instrument Factory, Shanghai Jingke, Juguang Yiyingxian, Jiji Swan, etc. However, there is no commercial amino acid analyzer in China. Foreign manufacturers of this instrument include Hitachi and Germany's SYKAM and AMINO.

1.7 Instruments and equipment for sample preparation

Agricultural product quality and safety testing is to detect μg, ng-level residues and contaminants in a very complex matrix. Traditional sample preparation techniques have become a bottleneck, and even helpless, so a series of new technologies will replace traditional instruments and equipment. These new instruments Have:

(1) Solid extractor (SPE). In 1978, Weters first introduced commercial instruments. Today, there are many manufacturers that use various adsorbents to extract, purify, and enrich samples. They are very mature and very popular.

(2) Solid phase microextraction instrument (SPME). It integrates the functions of extraction, purification, concentration, etc. It is compact, simple and easy to use directly with other analytical instruments. In 1994, Varian and Supelco first launched the fully automatic sampling / injection SPME instrument, and there are now many productions.

(3) Matrix solid phase dispersion extraction (MSPDE). It was first proposed in 2000. The advantage is that there is no need to perform traditional procedures such as homogenization, precipitation, centrifugation, pH adjustment, and sample transfer. The components to be tested can be obtained one by one to complete the whole process of extraction and purification.

(4) Supercritical fluid extraction instrument (SFE). The advantage is that it does not use organic solvents, is simple, efficient, fast, selective, and easy to connect with GC, LC, etc., but it is difficult to extract samples containing hydroxyl and carboxyl groups.

(5) Gel dialysis extraction instrument (GPC). It is transplanted to gel chromatography separation and analysis technology. The advantage is that the purification capacity is large, the recovery rate is high, and it is easy to connect with other instruments. The device needs to be more compact, dedicated, simple, and reduce the amount of solvent and column cost.

In addition to the above, other new technologies such as microwave digestion extraction instrument, microporous liquid membrane extraction, nano and magnetic bead enrichment extraction, as well as headspace sampling, purge and trap, automatic heating and pressure rapid solvent extraction instrument Etc., will play a role in the inspection of agricultural products and food safety. These instruments and equipment have also been developed and industrialized in China, and their performance has gradually approached that of foreign products. Manufacturers include: Shanghai Spectrum and Xinyi; Beijing Jitian, Ruili, Fengjiehua, and Chengdu Colin.

1.8 Small and medium-sized instruments and equipment necessary for the laboratory

In the past, when building a laboratory in China, we only paid attention to large instruments and equipment and ignored the necessary small and medium-sized commonly used supporting equipment, resulting in only a developed mind and no clever limbs. Large instruments are difficult to fully function. This should be given full attention. These small and medium-sized instruments and equipment should be selected according to the tasks and functional requirements determined by different centers. There are roughly: visible light / ultraviolet spectrometer, acidity meter, sample grinding mill, electronic balance, liquid dispenser, pipette, shaker, rotary evaporator, constant temperature water bath, biochemical incubator, drying oven, heating plate, centrifuge, stirring Sterilizer, sterilizer, homogenizer, ultra-static table, pure water device, refrigerator, freezer, sample cabinet, and microscope suitable for the task. Many enterprises in China produce these instruments, and their performance has been able to meet the actual requirements, and they can focus on the selection of domestic products. There are also many foreign product agents for small and medium-sized instruments and equipment with high requirements.

2. Prospects for rapid screening and testing techniques and instruments for food safety

China's agricultural products and food production and supply channels are numerous, large, small, scattered, complex, and the rule of law and self-discipline are very weak, and the population and consumer groups are large, resulting in frequent safety problems. In addition to environmental protection and production conditions and other factors, most of them stem from illegal use and abuse of pesticides, veterinary drugs and additives.

Due to the time-consuming sample preparation and expensive, complicated, and low-throughput testing instruments, it is difficult to monitor food safety in a timely, rapid, on-site, and source-wise manner if a series of laboratory testing techniques determined by a series of national and industrial standards are used. Measurement technology has special significance in China. There are many technical principles and instruments, but not many are perfect and mature, and even less has been industrialized in China. In recent years, related research and development at home and abroad has been very fierce. At present, the optimistic technologies and instruments mainly include the following 8 categories.

2.1 Immunoassay methods and instruments

Including radioimmunity, enzyme immunity, fluorescence immunity, chemiluminescence immunity and colloidal gold standard immunity. The enzyme-linked immunoassay technology has been listed as one of the three pillar technologies of residue detection by AOAC (American Association of Analytical Chemists). It has the characteristics of high specificity, accuracy, simplicity, and rapidness. It can detect pesticide and veterinary drug residues and cause Germs, viruses, toxins and genetically modified products. The US EPA has issued 12 items to screen for chlordane, pentachlorophenol, polycyclic aromatic hydrocarbons, polychlorobisphenol, mercury, atrazine, and toxaphene in soil and water related to agricultural environmental protection using ELISA. China has produced many enzyme-linked immunoassays, but it has not been widely used in food safety and environmental testing. One of the reasons is that the instrument has a single function, but the main reason is that the domestic kits are few in variety and the price of imports. expensive.

In the future, we should deeply study the various influencing factors of ELISA method, standardize and serialize the production of various kits, and develop towards recombinant antigens, multiple targets, targeted transformation of enzymes, in vitro molecular evolution, and automated enzyme-linked immunoassay technology.

2.2 Various biosensors

The biosensor has the characteristics of multiple functions, miniature, intelligence, integration, low cost, high sensitivity, high recognition and practicality. Its development is rapid and there are many types. SPR biosensors, which have been widely used in developed countries, are sensitive, fast, label-free, convenient, and real-time. It is strongly combined with other new technologies, and launched a batch of new rapid screening, detection methods and instruments, the most typical of which is represented by BiacoreAB and the United States TI and Bio-RAD (Molecular Interaction Instrument). Biacore combines SPR detection system, biosensor chip, microfluidic system, etc. with a variety of kits, which are used for rapid screening and detection of veterinary drug residues, pathogenic bacteria, toxins, etc. Japan is used to screen for dioxin. The Chinese Academy of Sciences Institute of Electronics has developed three SPR instruments, and Henan Agricultural University has also developed SPR instruments for the detection of veterinary drug residues. The overall development direction of SPR is high-throughput, high-sensitivity, small, and miniature, with portable functions.

Recently, it has been reported that the United States has developed new biosensors using nanotechnology, which can quickly and highly sensitively detect extremely small amounts of bacteria, viruses, parasites, and pathogens in food and water.

Microbial sensors, especially those with a highly sensitive luminescent response to toxic substances. Europe and the United States attach great importance to the research and application of luminescent bacteria, such as IS011348, using Fisher Vibrio bacterium to detect insecticides, herbicides, sterilizers, Aspergillus flavus, heavy metals, cyanide, toxins, nitro compounds, bromine compounds Wait. The use of ATP detection technology, that is, the use of adenosine triphosphate and luciferase luminescence reaction to detect the degree of microbial and organic contamination. In addition, there is a sensitive relationship between the vitality of iron oxidizing bacteria and pollution to detect harmful substances.

2.3 Biochip, microchip laboratory and portable microfluidic chip system

Such technology has the characteristics of high throughput, high sensitivity and fast detection. Great attention has been paid to its application in food safety, disease diagnosis, etc. internationally. The National Biochip Center of China has developed and produced biochip technology platforms (instruments and kits) for detecting foodborne pathogens, foodborne viruses and veterinary drug residues, and will further target the field, rapid testing and microchips The development of the laboratory. The China Academy of Inspection and Quarantine has now developed a portable microfluidic chip system using technologies such as microfluidics, biochips, and membrane enrichment, which, together with corresponding kits, can quickly screen for veterinary drug residues and viruses.

2.4 Special electrochemical sensors

Electrochemical sensors have the advantages of small size, sensitivity, diversity, and low cost. The use of special electrochemical sensors and the construction of fast food safety detectors have attracted widespread attention at home and abroad. China ’s East China Normal University and Changchun Institute of Applied Chemistry, etc. have combined nanotechnology and electrochemical technology to construct an instrument for rapid detection of toxic and hazardous heavy metals in food. The new nanoperoxide sensor and nanometal / oxide sensor constitute a rapid A rapid detector for detecting the total number of bacteria and E. coli. These kinds of speed measuring instruments have been included in the national science and technology support project.

2.5 Laser Raman spectroscopy, deep ultraviolet spectroscopy and near infrared spectroscopy analysis techniques and instruments

According to reports, the United States uses laser Raman to launch the detection technology known as "Crown Buster". The China Academy of Inspection and Quarantine also makes full use of the localized high-performance small laser and frequency stabilization technology to develop a portable high-sensitivity laser Raman spectrometer for rapid screening of melamine, with high sensitivity and semi-quantitative detection. Thermo Fisher introduced a new Raman spectrometer that can directly penetrate glass and plastic packaging, with high reproducibility and high characterization. All of these may become a good means of rapid screening. Even more gratifying is that the academician Xu Zuyan of our country pioneered the all-solid-state deep ultraviolet laser, whose energy resolution can be increased by 5 to 10 times and the photon flux density by 3 to 5 component levels. On this basis, Academician Li Can and others are developing ultra-high intensity laser Raman spectrometer. In addition, the deep ultraviolet photoluminescence spectrometer being researched by academician Wang Zhanguo and the deep ultraviolet photochemical reaction instrument being researched by academician Tong Zhenhe will be able to produce extremely sensitive absorption spectra for 90% of the existing 30 million organic compounds. In addition, there are cluster analysis and model recognition technology in near infrared spectroscopy to quickly identify the authenticity of brand products. These will create a new generation of spectrum analyzers.

2.6 Miniaturized time-of-flight mass spectrometer (TOF-MS) and ion mobility spectrometer (IMS)

At present, the international and domestic standard methods for food safety testing are based on the adaptation of the "two sisters" of gas and liquid phase chromatography (GC and LC) to various mass spectrometry (MS), but they must be small, portable, fast, On-site testing of food safety, chromatographs have difficulties, mass spectrometry is more difficult.

In response to emergencies such as terrorist attacks, aerospace, national defense, environment, and food, foreign countries first worked on ion trap mass spectrometry, and then turned to miniaturized TOF-MS and IMS. The Institute of Chemistry, Geochemistry, Optomechanics, etc. A series of results have been achieved in this regard. IMS is based on the characteristic migration time of different molecular ions in the sample in the drift tube at atmospheric pressure for rapid detection (microsecond level). It does not require a vacuum system, the device is very small, the cost is not high, and the sensitivity is extremely high, which can reach the pico (pg) level, and the latest detector can reach the feg (fg) level, and can distinguish isomers. IMS is a popular technology in the inspection and testing industry, and has great potential in the field of biomedicine and food safety rapid screening.

Although foreign countries have never provided IMS to our country, the Institute of Chemical Physics of the Chinese Academy of Sciences has made a series of breakthroughs and has its own characteristics and innovations, but it has yet to be expanded into the field of food safety testing. Because the analysis speed of the miniaturized TOF-MS is fast (microsecond level), the structure is simple, the resolution is about 600, and the mass number is 500. It is already capable of environmental testing, but it is still far from the requirements of food safety testing. However, on the basis of retaining the use of vacuum ultraviolet single photon ionization and membrane enrichment, the next step of expansion is just around the corner.

2.7 Fast measuring instruments based on classical molecular spectroscopy

Molecular spectroscopy is the most classic technique, which can be used for almost all detection tasks, but it can only be used for rough measurement, and it is difficult to undertake trace analysis. In recent years, based on analytical chemistry, Jilin University and Huaxia Science and Technology have integrated and optimized various kits with different detection targets and tasks, and adopted new technologies such as cluster cold light source / monochromator. High-precision, high-stability, modular portable instruments have been introduced, combined with rapid sample extraction and enrichment techniques, to constitute more than 40 parameters (such as nitrate, nitrite, formaldehyde, and nitrate) that can quickly detect food safety. The multi-parameter fast food safety tester of white block, taste, artificial pigment, inorganic arsenic, metal lead, inferior milk, "ditch oil", "swill oil" ...... Occupy a place.

2.8 Enzyme inhibition method and instrument

The enzyme inhibition method was proposed by the United States in 1951 and improved by Canada in 1968. China has started research and development in the 1980s. In recent years, more than a dozen commercial instruments have been launched and promoted. In view of the fact that this method can only detect organophosphorus and carbamate pesticides, and the inhibition rates of the same and different pesticides vary greatly, it is necessary to use a unified inhibition rate to determine whether pesticide residues exceed the standard, which will inevitably produce false positives or false Negative test is missed, so this is the current "quick test method of last resort", it is not appropriate to put the enzyme inhibition method and the instrument as the quick test technology. This method is only applicable to the primary inspection at the grass-roots level. When the phenomenon of exceeding the standard is found, it must be retested and confirmed by standard methods. This is clearly stipulated in Article 36, paragraph 2 of the Agricultural Products Quality Safety Law. Negative reactions should also be sampled in proportion and retested and confirmed with reliable methods.

Food safety rapid screening testing technology and instruments are the integration, derivation and grafting of new methods and instruments. There are more new technologies to be applied, and newer principles, technologies, processes, and materials will continue to emerge and be used in practice. For example, nanomaterials will be applied to sensors and detectors of a series of speedometers, thereby greatly improving sensitivity and stability; molecular imprinting technology with molecularly imprinted polymers as the core has high predeterminability, high recognition, and high selection And high stability, not only become a good means of separation and enrichment, if grafted into other rapid measurement methods and instruments, it will greatly improve the existing rapid measurement methods and instruments; high sensitivity chemiluminescence method and high Selective immunoassay method for a deeper combination, it is also possible to introduce a simple, high-precision chemiluminescence immunoassay method and instrument for rapid food safety testing. In short, rapid technological developments will enable rapid improvement, refurbishment, and introduction of new food safety screening and testing instruments, and make them more in line with the needs of actual testing.

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