Common problems in GLC chromatogram analysis include issues like peak tailing, peak broadening, and unexpected peaks. Peak tailing, where peaks have a longer trailing edge, can be caused by interactions of the sample with active sites in the column or by overloading the column with too much sample. To resolve this, one can deactivate the column's active sites or reduce the sample size. Peak broadening, where peaks appear wider and less defined, can result from factors like inefficient column packing, inadequate temperature control, or too slow a flow rate of the carrier gas. Addressing these operational issues can help sharpen the peaks. Unexpected peaks might arise due to impurities in the sample or contamination in the system. Ensuring sample purity and regular maintenance and cleaning of the GLC system can mitigate these issues. Understanding and addressing these common problems is essential for accurate and reliable GLC analysis.

The choice of detector in GLC can significantly affect the interpretation of chromatograms, as different detectors have varying sensitivities and selectivities for different compounds. Common detectors include the Flame Ionization Detector (FID), which is highly sensitive to organic compounds, and the Thermal Conductivity Detector (TCD), which is universal but less sensitive. The FID produces a response based on the number of carbon atoms ionised in a flame, making it extremely sensitive to hydrocarbons but less responsive to compounds lacking carbon, such as water. The TCD measures changes in thermal conductivity as different compounds pass through the detector, offering a broad response but with lower sensitivity. Choosing the right detector depends on the nature of the compounds being analysed and the level of sensitivity required. For instance, FID would be preferred for detecting low concentrations of organic compounds, while TCD would be suitable for a broader range of compounds, including inorganic gases.

GLC chromatogram analysis finds numerous applications in real-world scenarios outside the laboratory, primarily due to its precision in separating and identifying compounds. In the pharmaceutical industry, GLC is used for the quality control of raw materials and finished products, ensuring the correct composition and detecting impurities. In environmental analysis, it's employed to monitor air and water quality, detecting pollutants and hazardous substances at trace levels. The food industry uses GLC for analysing food products, such as determining the fatty acid content in oils or detecting additives and contaminants. In forensic science, GLC can identify substances in drug analysis and toxicological investigations. These applications demonstrate the versatility and importance of GLC in various fields, offering critical insights into the composition of diverse samples.

The length and diameter of the GLC column have a significant impact on the efficiency of separation and analysis. A longer column typically provides better separation of compounds, as it allows more interaction between the sample and the stationary phase. This increased interaction time results in better resolution and clearer separation of closely related compounds. However, longer columns also mean longer analysis times and may require more carrier gas. The internal diameter of the column influences both the capacity and the speed of analysis. A wider diameter allows for larger sample sizes but can lead to reduced resolution. Conversely, a narrow diameter column provides better separation and efficiency but limits the amount of sample that can be loaded. The choice of column dimensions depends on the specific requirements of the analysis, balancing the need for resolution, analysis time, and sample size. In practice, this means selecting an appropriate column length and diameter to achieve optimal separation for the compounds of interest within a reasonable timeframe.

The choice of stationary phase in GLC plays a crucial role in the separation and identification of compounds. The stationary phase is typically a high boiling point non-polar liquid, and its properties directly influence how different compounds interact with it. The principle of 'like dissolves like' applies here; compounds that are more similar in polarity to the stationary phase will have stronger interactions and, therefore, longer retention times. For instance, non-polar compounds will interact more strongly and for longer periods with a non-polar stationary phase, resulting in distinct separation from polar compounds, which interact less and elute faster. The choice of stationary phase thus affects the resolution of the chromatogram – the ability to distinguish between different compounds. When selecting a stationary phase, one must consider the nature of the compounds to be separated, ensuring it provides optimal interaction for effective separation and clear identification on the chromatogram.