Difference between gas chromatography and liquid chromatography.

I. Analyzing object difference.

1. Gas chromatograph analysis object.

(1) Good gasification, good thermal stability, low boiling point samples.

(2) High boiling point, poor volatility, poor thermal stability, ions and polymers samples can not be detected.

(3) Only 15 to 20 inches of organic matter.

2. High-performance liquid chromatography analytical object.

(1) Dissolved to make a solution of the sample.

(2) Not limited by the volatility and thermal stability of the sample.

(3) Large molecular weight, gasification difficulties, poor thermal stability, can detect polymers and ionic samples.

(4) Wide range of uses, about 80%-85% of organic matter.





II. Mobile phase differences.

1. Mobile phase of gas chromatography:

1) The mobile phase is an inert gas.

(2) There is no affinity between the components and the mobile phase, only the stationary phase plays a role.

2. Mobile phase of high performance liquid chromatograph:

(1) The mobile phase is liquid.

(2) The mobile phase works closely with the components to increase the column selectivity and improve the degree of separation, which plays an important role in separation.

(3) There are a variety of mobile phases with many options.

(4) The choice of mobile phase polarity and pH plays an important role in the separation.

(5) The selection of two or more liquids with different ratios as mobile phase can improve the separation selectivity.



III. The difference in working conditions.

1.Gas chromatography working conditions: heating work.

2.High performance liquid chromatography working conditions: room temperature, high pressure (high viscosity of liquid).