To determine the composition and respective concentrations of a given sample mixture using gas chromatography GC , follow these steps:1. Prepare the sample: First, ensure that the sample is suitable for gas chromatography analysis. It should be volatile or semi-volatile and thermally stable. If necessary, convert the sample into a suitable form by derivatization or extraction.2. Choose the appropriate GC column: Select a suitable stationary phase and column length based on the sample's chemical properties and the desired separation efficiency.3. Set up the gas chromatograph: Configure the instrument settings, such as carrier gas flow rate, oven temperature program, and detector type, based on the sample's properties and the desired analysis.4. Inject the sample: Introduce a known volume of the sample into the GC using an appropriate injection technique, such as split, splitless, or on-column injection.5. Analyze the chromatogram: As the sample components pass through the column and reach the detector, they will produce a chromatogram with peaks corresponding to each component. The retention time RT of each peak can be used to identify the components by comparing them to known standards.6. Quantify the components: Integrate the area under each peak in the chromatogram, which is proportional to the concentration of the corresponding component in the sample. Use calibration curves generated from known concentrations of standards to determine the concentration of each component in the sample.7. Report the results: Present the identified components and their respective concentrations in the sample mixture.Keep in mind that the accuracy and precision of the results depend on various factors, such as the quality of the standards, instrument performance, and the analyst's expertise. It is essential to follow good laboratory practices and validate the method to ensure reliable results.