The invention discloses a stability evaluation method of a
thermogravimetry-instillation microextraction combined
system, and belongs to the technical field of chemical analysis and testing. According to the method, a target compound and an
internal standard compound with volatility are utilized to realize stable and constant-speed volatilization under an
optimal test condition of a thermogravimetric-instillation microextraction combined
system, a parallel experiment is carried out through instillation microextraction according to the
optimal test condition, a plurality of liquid drops containing the target compound and the
internal standard compound at the same time are collected, and the target compound and the
internal standard compound are obtained. Measuring the concentration of the compound in the
liquid drop by using a
gas chromatography-
hydrogen flame ionization detector to obtain a plurality of groups of concentration values, respectively calculating the relative standard deviations SD1 and RSD2 of the concentration of the target compound and the internal standard compound, calculating the
concentration ratio of the target compound to the internal standard compound in each group and the
relative standard deviation RSD3 of the target compound and the internal standard compound in each group, and taking the three RSD values as an evaluation index of the stability of the
thermogravimetry-instillation microextraction combined
system, and indicating that the stability of the combined system is good if the RSD1 is less than or equal to 10%, the RSD2 is less than or equal to 10% and the RSD3 is less than or equal to 5% in a required range.