Method for efficiently detecting residual solvent in poly-L-lactic acid and preparation thereof

The invention discloses a gas chromatographic method for a residual solvent in poly-L-lactic acid, which comprises the following steps: taking cyanopropyl phenyl-dimethyl polysiloxane as a stationary phase of a capillary gas chromatographic column, controlling the initial temperature at 35-50 DEG C, heating to 160-280 DEG C at the rate of 5-20 DEG C per minute, keeping the temperature for 3-15 minutes, and injecting a sample; the temperature of a sample inlet is 200-250 DEG C; the temperature of the detector is 220-320 DEG C; the carrier gas is nitrogen, the flow rate is 2.0-5.0 ml/min, the split ratio is (8-15): 1, headspace sampling is performed, the sampling amount is 1-10 ml, and the residual solvent is selected from any one or a combination of methylbenzene, benzene, dichloromethane, trichloromethane, ethanol, acetone, ethyl acetate, normal hexane, cyclohexane, tetrahydrofuran, chloroform, normal heptane, isopropanol and methanol. The method disclosed by the invention is high in sensitivity and good in a