Did you know that VOCs pretreatment and detection techniques commonly used in laboratories?

In addition to sample collection, VOCs detection technology also focuses on sample pre-treatment and detection techniques. The detection of new technologies on VOCs detection, monitoring, emission reduction has a great role in promoting. This time to introduce you to commonly used laboratory VOCs detection technology. Sample preparation VOCs sample pretreatment methods: Solvent analysis, low temperature preconcentration - thermal desorption, solid phase microextraction and so on. 1.1 solvent desorption method The common desorption solution of solvent desorption method is carbon disulfide. Although this method of analysis of larger errors, but simple and convenient. 1.2 low temperature preconcentration - thermal desorption method Thermal desorption has high sensitivity, anti-interference, to avoid leakage, decomposition and desorption when using adsorbent. Can be directly injected into the sample analysis. High sensitivity, environmental protection, sample storage time. 1.3 Solid Phase Microextraction SPME With the characteristics of high selectivity and easy operation, the application of VOCs in monitoring gradually increases. The disadvantage is that SPME is a dynamic equilibrium process that requires correction and is suitable for collecting compounds of known structure with the disadvantage of poor reproducibility. 1.4 cold trap sample enrichment Divided into ultra-low temperature refrigeration, electronic refrigeration and liquid nitrogen refrigeration method. Ultra-low temperature cooling method (≤? 150 ℃) The sample quickly through the connector into the automatic injection system, and then into the multi-stage cold trap preconcentration system for enrichment, can be concentrated several times. Commonly used is a multi-stage series cold trap: the target compound is transferred from the previous cold trap to the next very cold trap, the first cold trap is slowly warmed, and the water vapor transfer is stopped. Currently common multi-stage cold traps have two cold traps and three cold traps.

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