How do you analyse a chromatogram?

A chromatogram is analysed by identifying and quantifying the components based on their retention times and peak areas.

In more detail, a chromatogram is a visual output from the chromatography process. It presents a series of peaks, each representing a different component in the mixture. The first step in analysing a chromatogram is to identify the components. This is done by comparing the retention times of the peaks in the sample chromatogram to those of known substances. The retention time is the time it takes for a component to travel from the injection point to the detector. Different substances have different retention times, so this can be used to identify them.

Next, the quantity of each component is determined. This is done by measuring the area under each peak. The larger the area, the greater the quantity of that component in the mixture. This is because the height and width of the peak are proportional to the concentration of the component in the sample. Therefore, by measuring the area under the peak, you can determine the relative amounts of each component.

It's important to note that the baseline of the chromatogram should be clear and the peaks should be well-resolved for accurate analysis. Overlapping peaks can make it difficult to accurately measure the area under each peak and can lead to errors in quantification.

In addition, it's crucial to calibrate the chromatography system with known standards before analysing the sample. This ensures that the retention times and peak areas are accurate and reliable. Calibration involves running a sample of known composition through the system and recording the resulting chromatogram. This provides a reference against which the sample chromatogram can be compared.

In conclusion, analysing a chromatogram involves identifying the components based on their retention times and quantifying them based on the area under their peaks. This requires a clear baseline, well-resolved peaks, and calibration with known standards.