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Comparison of various quantitative analysis methods in GC: For samples with relatively low quantitative requirements, the normalization method can be used when the relative correction factors for all components are known. Since the analysis of samples is performed in a single injection, there are not very high requirements regarding the stability of the chromatographic analysis conditions or the accuracy of the sample volume injected; however, whether the appropriate correction factors are used does affect the quantitative results. For a large number of analysis samples, the external standard method is more appropriate. The slope of the external standard curve is essentially the quantification correction factor; therefore, in quantitative analysis, in addition to accurate measurement and high sample purity, any factors that affect the area of the chromatographic peak will have a direct impact on the correction factor. As a result, it is necessary for the chromatographic operating conditions to be repeatable and stable. Moreover, the curve must be corrected after some time. The internal standard method is suitable for analyzing samples in small quantities. When no appropriate internal standard is available, the additional internal standard method can be used. Since the internal standard and the analyte are injected together through the same needle, the stability of the chromatographic analysis conditions and the accuracy of the injection volume require not to be very high. However, as the internal standard is included in the calculations, high requirements are placed on its quantity and purity. (The addition method involves preparing a chromatogram using a certain amount of sample, then precisely adding the peak area of the component to be measured to the same amount of sample; the difference between these two values represents the peak area of the pure substance added. The concentration of the component in the sample can be calculated based on the amount of this pure substance. Since it is difficult to control the amount of sample injected, the internal standard method is more commonly used.) ）