Introduction to modern technology of sample pretreatment (1)

1.

There are many substances that can be used as supercritical fluids, such as carbon dioxide , methanol , ethanol , and ammonia

2.

The extraction of organics by SPME conforms to the principle of "similar compatibility"

The SPME device is a little like a sample injector.

3.

Accelerated Solvent Extraction (ASE) is a method developed in the 1990s to extract organic compounds from solid substances

Figure 1-10 Diagram of solid phase microextraction device

The principle of accelerated solvent extraction is to select a suitable organic solvent based on the principle of "similar miscibility", and to increase the efficiency of the extraction process by increasing the temperature (50-200°C) and pressure (10.

The accelerated solvent extraction instrument is composed of solvent bottle, pump, gas circuit, heating furnace, stainless steel extraction tank and collection bottle, etc.

Figure 1-11 Accelerated solvent extraction device and work flow chart

4.

This method is a new type of sample digestion technology.

5.

Microwave extraction technology started from the Hungarian scholar Ganzlerk

The basic principle of microwave extraction is that the microwave directly interacts with the separated substance.

Compared with traditional Soxhlet extraction and ultrasonic extraction, the main features of microwave extraction are rapid, energy-saving, good reproducibility, saving reagents, and low pollution; microwave heating is selective and can process multiple samples at the same time; thermal efficiency High, rapid and uniform heating, which is good for extracting materials that are unstable to heat, can avoid the decomposition of samples caused by high temperature for a long time, and help the extracted materials to desorb from the sample matrix.