A Study on Improvement of the Analytical Method of Chlorantraniliprole Residue in Herbal Medicine (Rehmannia glutinosa Libosch) using HPLC-UVD

초록

This study was conducted to develop a possible method for chlorantraniliprole in R. glutinosa root using HPLC-UVD. Acetonitrile/n-hexane and dichloromethane/d-water partitioning methods were used to remove non-polar and polar interfering substances in R. glutinosa root extract, respectively. Unlike agricultural products that usually go through one-time refining process, R. glutinosa root had difficulty removing impurities and it could be analyzed only after two consecutive SPE refining processes. Thus double cleaning up using SPE-silica and SPE- NH2 cartridges were continuously used. The respective n-hexane/ethyl acetate and n-hexane/acetone elution were used for SPE-silica and SPE-NH2. Gradient conditions were used to establish the optimal HPLC-UVD-analysis conditions for quantitative-analysis. Wavelength of 230 nm was selected after scanning the absorbance of wavelengths for minimizing the effect of interfering substances. The MLOQ was 0.02 mg/kg, recovery rate ranged 87.9-105.2% after reviewed at 0.02 and 0.2 mg/kg and RSDs was 3.0%. Chlorantraniliprole was verified by LC-MS SIM mode and the recovery was 90.1-106.9%. Cross-laboratory validation of this method found that the average recovery and RSD were 88.4% and 0.3%, respectively. Chlorantraniliprole met the criteria of validation parameters (acceptable recovery 70-120% and RSD <10%). This study carried out two clean up processes methods and changing UV spectra, after two consecutive refining processes with two kinds of SPE, significant interference materials were eliminated, but found it was difficult to completely separate the chlorantraniliprole from R. glutinosa matrix. However, it is believed that this study could be used in some domestic and/or developing countries' laboratories using conventional instruments to research pesticide residues analysis in herbal medicines.

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