Introduction to common instruments for food safety testing and their advantages and disadvantages

First, mass spectrometer

Mass spectrometry (MS), the trend of food safety testing, the scope of popularity has a tendency to exceed the liquid phase, characterized by qualitative testing, combined with other methods, can deal with all unknown substances, but the price is quite high, the general laboratory does not Dare to ask.

Advantages: qualitative testing to enhance the status of the laboratory;

Disadvantages: expensive, expensive internal standard, expensive consumables.

Second, the laboratory routine small equipment

Ultraviolet luminometers, infrared absorption photometers, and nitrogen analyzers are inexpensive, simple, and practical. When lean meat is coming, when melamine is rampant, the most intimate thing for the experimenter is the small-scale equipment such as solid phase extraction, shaker, and nitrogen blowing.

Advantages: bring a lot of convenience to the experiment, the price is cheap;

Disadvantages: The current level of automation of small instruments is not high.

Recommended: ultraviolet photometer; infrared absorption photometer; nitrogen analyzer; microplate reader; nitrogen blowing instrument; solid phase extraction instrument; ultrasonic cleaner, high speed homogenizer; circumferential oscillator; shaker; constant temperature drying oven; Aseptic table; water bath; rotary evaporator.

Third, atomic fluorescence photometer

AFS atomic fluorescence, characteristic of a gaseous free-atomic absorption source, after the outer electron of the atom transitions to a higher energy level, and then transitions back to the ground state or lower energy level, while emitting the same or different emission as the original excitation wavelength. Atomic fluorescence. The method of detection by the detector.

Advantages: low detection limit, high sensitivity and low price;

Disadvantages: low degree of automation

Atomic absorption spectrophotometer

AAS atomic absorption is a method for quantitative analysis based on the absorption of specific atomic lines by atomic vapor generated by a substance, and is a common method for detecting elements.

Advantages: fast detection speed, easy operation and good selectivity;

Disadvantages: The detection limit is high.

Five, gas chromatograph

GC gas chromatography, using gas as a mobile phase of a chromatography method, the entire separation process is poly-ionization, re-polymerization, and separation. The method can analyze low-boiling components and is widely used in the detection of pesticide residues, especially organic phosphorus and organic chlorine.

Advantages: a good separation of low-boiling, low-molecular-weight organics using a variety of different columns.

Disadvantages: There are not many substances that can be analyzed. In order to lower the boiling point, it is sometimes necessary to derivatize and other treatment methods, and it is not qualitative.

Six, liquid chromatograph

LC liquid chromatography, liquid chromatography can analyze 75%-80% of organic matter, is the most widely used analytical method, the necessary tool for analytical laboratories.

Advantages: Near-perfect performance in the field of food safety testing,

Disadvantages: Uncharacteristic

Seven, biological methods

Biological methods, especially immunological methods, although not used as qualitative methods, have an absolute advantage in the speed and portability of detection. Moreover, with the development of immunological techniques in recent years, the detection limits of immunological methods are limited. To a large extent, at present, drug residues such as clenbuterol, ractopamine, salbutamol, chloramphenicol, etc., have already had very mature immunological detection methods and have been widely used.

Advantages: convenient, portable and fast;

Disadvantages: Uncertainty, easy to be interfered by external factors, easy to be unstable

Recommended: a variety of ELISA test kits, gold standard test strips.