| Chinese herbal medicine as a cultural treasures in china, plays an important part in the health of the Chinese. With the inscreasing use of the pesticides both in amount and in spectrum, more attention given to residues in Chinese herbal medicines and their harms on human health and the environment. This could seriously affect the repution of Chinese herbal medicines in international market. Therefore, it was urgent and significant to strengthen the study on determination of pesticide residues in Chinese herbal medicines. In this study, we systematically studied the determination methods of pesticide residues in Chinese herbal medicines, using ultra high performance liquid chromatography-tandem mass spectrometry technology to establish a simple, rapid and selective method. The main result of this study were as follows:1. An ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was developed for the determination of 11 carbamate pesticide residues in glycyrrhizae radix et rhizoma , astragali radix and their extracts. After extracted by acetonitrile and cleaned up by gel permeation chromatograph (GPC), the samples was determined by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry in postive mode ( ESI+ ). Glycyrrhizae radix et rhizoma and its extract were analysed as examples. When the spiked levels were 0.02, 0.04, and 0.1 mg kg-1, the average recoveries of 11 carbamate pesticides in glycyrrhizae radix et rhizoma were obtained from 72.2% to 94.0%, the relative standard deviations (RSDs) ranged from 0.7% to 7.8%; while the average recoveries of 11 carbamate pesticides in glycyrrhizae radix et rhizoma extract ranged from 73.8% to 94.7% and the RSDs ranged from 1.5% to 12.7%. The sensitivety accuracy, and precision of this method can met the requirements of the pesticide residue analysis and this method was applied to determine 11 carbamate pesticides residue in glycyrrhizae radix et rhizoma, astragali radix and other similar herbal plants.2. A screening method was developed for the detennination of 14 carbamate pesticide residues in carthami flos using off-line dispersive solid-phaseextraction (DSPE) and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry. After extracted by acetonitrile and simultaneously separated by liquid-liquid partitioning with adding anhydrous magnesium sulfate plus sodium acetate following by a simple cleanup step known as dispersive solid-phase extraction.The extract was determined by UPLC-MS/MS using external standard method.The linear range was 0.005 - 0.20 mg/L . The average recoveries of 14 carbamate pesticides in carthami flos at four spiked levels (0.01, 0.02, 0.04, 0.08 mg kg-1) ranged from 95.0% to 106.2% (n=6) , and relative standard deviations ( RSDs ) ranged from 1.0% to 7.5%; the limits of detection and the limits of quantification were 0.2～3.5μg kg-1 and 0.7～11.7μg kg-1, respectively. The results indicated that the methd is easier, faster and the sensitivity, accuracy, and precision of this method can met the requirements of the pesticide residue analysis, and the method can be applied to determination carbamate pesticide residues in carthami flos and other Chinese medicinal herbs.3. Dispersive solid-phase extraction (DSPE) cleanup combined with accelerated solvent extraction (ASE) was described here as a new approach for the extraction of carbamate pesticides in Radix Glycyrrhizae samples prior to UPLC-MS/MS. In the DSPE-ASE method, 15 carbamate pesticides were extracted from Radix Glycyrrhizae samples with acetonitrile by the ASE method at 60℃with a 5 min heating time and two static cycles. Cleanup of a 1 mL aliquot of the extract by the DSPE method used 20 mg PSA, 50 mg Al2O3-N, and 20 mg GCB (as cleanup sorbents) under the determined optimum conditions. The linearity of the method was in the range of 10 to 200 ng mL-1 with correlation coefficients (r) of more than 0.996. The limits of detection were approximately 0.2 to 5.0μg kg-1. The method was successfully used for the analysis of target pesticides in Radix Glycyrrhizae samples. The recoveries of the carbamate pesticides at the spiking levels of 0.05, 0.1 and 0.2 mg kg-1 ranged from 79.7% to 99.3% with relative standard deviations lower than 10%. This multi-residue analytical method allowed for a rapid, efficient, sensitive and reliable determination of target pesticides in Radix Glycyrrhizae and other medicinal herbs.
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