Question

1) How i measure the chromatography step by step?

2) How i measure the Spectrscopy step by step?

Answer 1

1. Gas chromatography can be used in the following steps to measure the concentration of a sample using a gas chromatograph

1. Determine the column, detector, injector and carrier gas according to the analysis you are going to do.
2. Turn the gas chromatograph machine and check for the accessories if they are attached properly and working fine
3. Now enter the values of commands on the software, such as temperature, valve duration etc.
4. Now let the chromatograph perform a blank run in which it clears itself from the residues of the last run. A blank run operates without the injection of the sample
5. Now inject the calibration gas and start a run. Perform several runs to account for the error by varying the concentration, retention time etc.
6. Enter the values of calibration concentration from step 5 into the software available. It will set a calibration standard in the machine.
7. Again perform a blank run to clean the machine before the sample run.
8. Inject the sample gas into the gas chromatograph and the machine will tell the concentration of the sample injected.

2 A spectrophotometer can be used to analyze the unknown sample in the following steps:

1. First of all turn the spectrophotometer ON and let it warm itself for a few minutes.
2. Clean the test tube you are going to use for accuracy in the analysis.
3. Now fill the test tube with a proper volume of the sample you are going to analyse.
4. Now in another test tube prepare a control solution i.e. only solvent should be filled in the test tube. This solvent is one which is present in the sample too , of the same volume as of the sample.
5. Choose a wavelength of light with which you are going to perform the analysis. Use of monochromatic wavelength provide better results.
6. Now place the blank solution or control solution in the holder and cover the lid. Calibrate the machine at zero concentration.
7. Now remove the blank solution and insert the sample which you want to analyse. Record the values of absorbance, transmitance etc displayed by the machine.
8. Repeat step 7 with varying wavelength of light and note the values.
9. Now plot a graph of absorbance v/s wavelength of light.

Compare your plot with the standard plots of the compounds you tested. This helps to analyse the concentration and impurities present in the sample.

Thanks.