This experiment is from the official website of College of Chemistry, Qingdao University of Science and Technology.
Operation method
Chromatographic determination of mixed samples of methyl acetate, cyclohexane and methanol
Principle
f', f can be obtained from the literature, or can be measured directly. Accurately weigh a certain weight of the substance to be measured and the standard substance, mix well and feed the sample, and then measure the peak area separately to find the correction factor. (3) Choose the appropriate quantitative method There are many kinds of quantitative methods in common use, and this experiment adopts the normalization method. The normalization method is to find out the peak area and correction factor of all components in the sample, and then find the percentage content of each component in turn. Advantages of the normalization method: it is simple; the sample volume does not need to be accurate; and it has little effect on the results when the conditions change. Disadvantages: all components in the mixture must be all peaks; all peak areas must be measured. Move I. Chromatographic conditions Caveat 1、Determine the attribution of each peak according to the retention time. 2、Calculate the relative correction factor according to the weight of the weighed specimen and the area of each peak (with methanol as the standard). 3、According to the peak area in the unknown sample, calculate the percentage content of each component in the sample to be tested by normalization method. For more product details, please visit Aladdin Scientific website.
Column: GDX-102 (60-80 mesh).
Temperature: Tc-100-120℃; TD-150℃; Ti-150℃
Carrier gas: H2 45 mL/min; N2 50 mL/min; air 400 mL/min
Paper speed: 5 cm/min; attenuation: self-selected
Second, according to the above conditions of the start-up and debugging, and then carry out the instrument in order after it is stabilized.
1. Qualitative analysis
(1) Adjust the speed of the recording paper to 5 cm/min, with a 1 uL syringe into the methanol, methyl acetate, cyclohexane 0.0%. (1) Adjust the speed of recording paper to 5 cm/min, and feed 0.1 uL of methanol, methyl acetate and cyclohexane into a 1 uL syringe, record the chromatogram, and accurately measure the retention time of each peak (tR).
(2) Under the same conditions, feed 0.1 uL-0.2 uL into the three-component mixture to record the chromatogram, and accurately measure the retention time (tR) of each peak.
2. Measurement of the correction factor
Weigh the three standard samples accurately on an analytical balance and mix them with the same vial, and then feed 0.1 uL-0.2 uL into the samples under set conditions, and record the peak area.
3. Quantification
Feed 0.1 uL-0.2 uL into an unknown mixture of the sample. sample. Record the chromatogram and measure the peak area.
4. Shutdown.