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Chromatographic testing has now penetrated into all walks of life and is a standing instrument for major testing and analysis laboratories
.
Chromatography is mainly divided into gas chromatography (GC) and liquid chromatography (HPLC), but they are very different
.
The differences between second-hand gas and liquid chromatographs are now explained from the following aspects! Comparison of second-hand gas and liquid chromatographs - working principle GC: It is composed of a gas system, a sample injection system, a separation system, a temperature control system and a detection and recording system
.
Gas chromatographs use gas as the mobile phase (carrier gas)
.
After the sample is "injected" into the injector by the microinjector, it is carried by the carrier gas into the packed column or capillary column
.
Due to the difference in the distribution or adsorption coefficient of each component in the sample between the mobile phase (gas phase) and the stationary phase (liquid or solid phase) in the chromatographic column, under the flushing of the carrier gas, each component repeats many times between the two phases.
The sub-distribution allows the components to be separated in the column, and then the detectors connected to the column are used to detect the components in sequence according to their physicochemical properties
.
HPLC: It consists of a liquid reservoir, a pump, a sampler, a chromatographic column, a detector, and a recorder
.
The mobile phase of the liquid chromatograph is pumped into the system by the high-pressure pump, the sample solution enters the mobile phase through the injector, and is loaded into the chromatographic column (stationary phase) by the mobile phase.
With different distribution coefficients, when the two phases move relative to each other, after repeated adsorption-desorption distribution processes, each component has a large difference in the moving speed, and is separated into a single component and flows out of the column in turn.
, When passing through the detector, the sample concentration is converted into an electrical signal and transmitted to the recorder, and the data is printed out in the form of a map.
Compared with liquid chromatograph - analytical object GC: suitable for samples with high degree of vaporization, good thermal stability and low boiling point; but for samples with high boiling point, poor volatility, poor thermal stability, ions and high polymers, especially For most biochemical samples, less than 20% organic matter was detected
.
HPLC: It is suitable for samples that can be dissolved into solutions (including organic medium solutions).
It is not limited by the volatility and thermal stability of the sample.
It is a biochemical sample with large molecular weight, difficult gasification and poor thermal stability.
, polymers and ions
.
Type samples can be used for a wide range of applications and account for 80% of organics
.
Comparison of used gas and liquid chromatographs - mobile phase GC: The mobile phase is inert, the gas components have no affinity with the mobile phase, and only interact with the stationary phase
.
HPLC: The mobile phase is a liquid, and the mobile phase and components have synergistic forces, which can improve the selectivity of the chromatographic column, improve the resolution, and play a positive role in separation
.
In addition, there are many types of mobile phases and a wide range of room options
.
The separation can also be adjusted by changing the polarity and pH of the mobile phase
.
Separation selectivity can be improved when two or more liquids with different ratios are selected as mobile phases
.
Used Gas vs.
Liquid Chromatographs - Operating Conditions GC: Warming Operation
.
HPLC: room temperature, high pressure
.
.
Chromatography is mainly divided into gas chromatography (GC) and liquid chromatography (HPLC), but they are very different
.
The differences between second-hand gas and liquid chromatographs are now explained from the following aspects! Comparison of second-hand gas and liquid chromatographs - working principle GC: It is composed of a gas system, a sample injection system, a separation system, a temperature control system and a detection and recording system
.
Gas chromatographs use gas as the mobile phase (carrier gas)
.
After the sample is "injected" into the injector by the microinjector, it is carried by the carrier gas into the packed column or capillary column
.
Due to the difference in the distribution or adsorption coefficient of each component in the sample between the mobile phase (gas phase) and the stationary phase (liquid or solid phase) in the chromatographic column, under the flushing of the carrier gas, each component repeats many times between the two phases.
The sub-distribution allows the components to be separated in the column, and then the detectors connected to the column are used to detect the components in sequence according to their physicochemical properties
.
HPLC: It consists of a liquid reservoir, a pump, a sampler, a chromatographic column, a detector, and a recorder
.
The mobile phase of the liquid chromatograph is pumped into the system by the high-pressure pump, the sample solution enters the mobile phase through the injector, and is loaded into the chromatographic column (stationary phase) by the mobile phase.
With different distribution coefficients, when the two phases move relative to each other, after repeated adsorption-desorption distribution processes, each component has a large difference in the moving speed, and is separated into a single component and flows out of the column in turn.
, When passing through the detector, the sample concentration is converted into an electrical signal and transmitted to the recorder, and the data is printed out in the form of a map.
Compared with liquid chromatograph - analytical object GC: suitable for samples with high degree of vaporization, good thermal stability and low boiling point; but for samples with high boiling point, poor volatility, poor thermal stability, ions and high polymers, especially For most biochemical samples, less than 20% organic matter was detected
.
HPLC: It is suitable for samples that can be dissolved into solutions (including organic medium solutions).
It is not limited by the volatility and thermal stability of the sample.
It is a biochemical sample with large molecular weight, difficult gasification and poor thermal stability.
, polymers and ions
.
Type samples can be used for a wide range of applications and account for 80% of organics
.
Comparison of used gas and liquid chromatographs - mobile phase GC: The mobile phase is inert, the gas components have no affinity with the mobile phase, and only interact with the stationary phase
.
HPLC: The mobile phase is a liquid, and the mobile phase and components have synergistic forces, which can improve the selectivity of the chromatographic column, improve the resolution, and play a positive role in separation
.
In addition, there are many types of mobile phases and a wide range of room options
.
The separation can also be adjusted by changing the polarity and pH of the mobile phase
.
Separation selectivity can be improved when two or more liquids with different ratios are selected as mobile phases
.
Used Gas vs.
Liquid Chromatographs - Operating Conditions GC: Warming Operation
.
HPLC: room temperature, high pressure
.
