Then advanced technology, therefore. Also obey the practicality, otherwise there will be no vitality. A major change is the many items, the 2003 version of the Food Hygiene Testing Methodology series. Especially for the pre-treatment of pesticide projects, solid phase extraction technology is commonly used. Now the principle, use and misunderstanding of this technology are discussed. . one. Introduction to solid phase extraction technology Developed in the 1970s, SolidPhase Extraction is referred to as SPE technology. Due to its high efficiency, reliability, and low consumption of reagents, many fields have replaced conservative liquid-liquid extraction and become an effective means of sample preparation. This is actually one of the main sources of improper use. Think of the SPE cartridge as a liquid chromatography column. Some traditional introductions to SPE books attribute it to the principle of a liquid chromatography. It is better to think of it as a simple extractant because: the focus of liquid chromatography is on separation, while the focus of SPE is on extraction. The second is enrichment. The role of the solid phase extraction device in sample disposal is divided into two types: one is purification. These two effects may exist simultaneously Its strength lies in the convenience and consumption of less reagents, compared to solid extraction and liquid-liquid extraction. The shortcoming is that the repeatability between batches is difficult to guarantee. The reason for this is that the reproducibility of the liquid reagent is good, as long as the purity is reliable, the physicochemical properties of the products of different ages are reliable, and the solid extractant guarantees the purity, and there is also a difference in the granularity. The difference in shape and other liquid reagents are not present and difficult to measure. The extraction properties of different batches may vary greatly in different years. Solid phase extraction should be well applied in the pretreatment of chromatographic analysis: organic solvents are used very little, theoretically and by manufacturers. The sample can be processed in batches, which can be both enriched and decontaminated, giving the impression of a revolutionary advancement in pretreatment. However, the reality is at least in China. Although it has been promoted for many years, the practical application is quite limited. Related to my approach and expectations, SPE is not widely used. It is also related to its own limitations. For suppliers, starting from economic interests has always neglected the limitations and shortcomings of solid phase extraction. Solid phase extraction can be a good supplement to the pretreatment method, but when using it, be sure to know the advantages and disadvantages, pay attention to local conditions, and avoid weaknesses. Second, the application advantages of solid phase extraction That is, solid phase extraction is more desirable than ordinary solvent extraction, and pre-treatment of any project is suitable for solid phase extraction. Personally think that there are several situations: a) Pretreatment of organic matter in water. The advantage of solid phase extraction is that such conventional treatments are essentially oscillating extractions with an organic solvent that is immiscible with water. 1 The pretreatment process can be repeated quantitatively. However, the oscillation frequency cannot be controlled, and the operation of the solvent oscillation generally only requires the level of the control time. Strength, action, know, each person's oscillating action is different from the same person, and it is difficult to guarantee a consistent action. Therefore, the action of solution extraction is not quantitative and cannot be repeated. It is easier to adhere to the uniformity and stability of the column and elution rate, while applying solid phase extraction. Therefore, the extraction process of solid phase extraction is reproducible and quantifiable.
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