Detection method of polyethylene glycol monomethyl ether residue in medicinal materials

A detection method of polyethylene glycol monomethyl ether (mPEG-2000) residue in mPEG-b-PDLLA comprising steps of:

• 1) providing a high-performance liquid chromatography (HPLC) chromatographic device as follows:
• setting an evaporative light scattering detector of the high-performance liquid chromatography (HPLC) device to operate at:
• a gain:
• 100-200, a drift tube temperature:
• 90-100° C., and a physicochemical gas pressure:
• 35-40.0 psi;
• setting a liquid chromatography column of the high-performance liquid chromatography device, which includes a high-purity silica gel matrix as a filler in the column to operate at:
• a flow rate:
• 0.8-1.0 ml/min;
• a column temperature:
• 25-35° C.;
• and
• an injection volume:
• 20 uL;
• introducing a mobile phase A into the high-performance liquid chromatography column having:
• a volume ratio of 95:5 of 0.3 mmol/L ammonium acetate solution:acetonitrile, containing 0.2% acetic acid;
• and
• then introducing a mobile phase B into the high-performance liquid chromatography column having:
• a volume ratio of 5:95 of 0.3 mmol/L ammonium acetate solution:acetonitrile, containing 0.2% acetic acid;
• 2) drawing a standard curve, which specifically comprises steps of:
• dissolving a mPEG-2000 reference substance in the mobile phase A to prepare
• mPEG-2000 standard solutions with different gradient concentrations between 25 μg/ml and 100 μg/ml, and detecting the mPEG-2000 concentration of the solutions with the detector of the chromatography device after filtration of the solutions in a filter having a pore size of 0.45 microns;
• during the detecting, introducing the mobile phase A and the mobile phase B as a gradient elution solution:
• from 0-10 minutes after a starting of elution, the elution solution comprising the mobile phase A being 85% of the elution solution, and the mobile phase B being 15% of the elution solution;
• from 11-30 minutes after the elution starting the mobile phase A being 65% of the elution solution, and the mobile phase B being 35% of the elution solution;
• from 31-40 minutes after the elution starting the elution solution comprising the mobile phase A being 50% of the elution solution, and the mobile phase B being 50% of the elution solution;
• and from 41-45 minutes after the elution starting, the elution solution comprising the mobile phase A being 85% of the elution solution, and the mobile phase B being 15% of the elution solution;
• and
• using logarithmic values of chromatographic peak areas as ordinates and logarithmic values of concentrations of the mPEG-2000 standard solutions as abscissas, plotting test results of the high-performance liquid chromatography as standard curves and then fitting to obtain a standard curve equation:
• Y=KX+b,
• wherein Y refers to the logarithmic values of the chromatographic peak areas, X refers to the logarithmic values of the mPEG -2000 concentrations, and K and b are constants;
• 3) preparing a test sample, which specifically comprises steps of:
• preparing the mPEG-b-PDLLA into a sample solution with a mPEG-b-PDLLA concentration of about 9.9-10.5 mg/mL and comprising the mobile phase A;
• and
• 4) detecting the mPEG-2000 residue in the sample solution with the detector of the chromatography device, which specifically comprises steps of:
• loading the sample solution in the column, and then loading the mPEG-2000 standard solutions in the column;
• comparing chromatograms of the sample solution and the standard solutions;
• identifying the mPEG-2000 in the sample solution by a difference of time where the mPEG-2000 is retained between the sample solution and the standard solutions;
• placing a logarithmic value of a chromatographic peak area of the mPEG-2000 in the test sample into the standard curve equation to calculate a concentration of the mPEG-2000 in the sample solution, and then calculating a residual amount of the mPEG-2000 in the sample solution.