Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

Simultaneous Determination of Saponins in Radix Glycyrrhizae, Notoginseng and Ginseng by High Performance Liquid Chromatography

To establish a method for determining five saponins(notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, ginsenoside Rb1 and ammonium glycyrrhizinate) in Glycyrrhizae, Notoginseng and Ginseng, the high performance liquid chromatography with diode array detector(HPLC-DAD) method was applied to an Inertsil ODS-SP column(4.6 mm×250 mm, 5 μm) with a mobile phase consisting of acetonitrile-0.05% phosphoric acid in a gradient elution manner. The flow rate was 1.0 mL/min. The column temperature was 30 ℃ and the detection wavelengths were 203 nm and 237 nm, respectively. The linear ranges were 0.700,0—7.000,0 μg for R1(r=1.000,0), 0.751,1— 7.511,4 μg for Rg1(r=1.000,0), 0.677,2—6.771,6 μg for Re(r=1.000,0), 0.733,9—7.339,1 μg for Rb1(r= 1.000,0), and 0.540,0—5.399,8 μg for ammonium glycyrrhizinate(r=0.999,9), respectively. In addition, their average recoveries were 100.28%, 105.83%, 104.09%, 99.36% and 98.54%, respectively. The relative standard deviations(RSDs) of precision, reproducibility and recovery were all less than 1.5%. The results indicate that the method is simple, accurate and reproducible so that it can be used for the simultaneous determination of the five saponins in Chinese patent medicines containing the three kinds of herbs.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD

Microwave-assisted extraction(MAE)was used for extraction of effective components of sarcandra glabra(Thunb.),and then chromatographic fingerprint of sarcandra glabra(Thunb.)was studied by high performance liquid chromatography/diode array detector(HPLC/DAD).The conditions of MAE were optimized by an orthogonal experiment,and then the authentication and validation of the chromatographic fingerprint were conducted.Nine peaks were identified as common peaks in the fingerprint chromatograms,and isofraxidin was considered as a reference compound and quantified.Relative standard deviations of retention time and peak area of each component were less than 3% and 8%,respectively.Similarity and difference analysis were conducted by use of PCA and relation coefficient.Twenty batches of sarcandra glabra(Thunb.)samples from two different producing areas could be classified into two different groups in the PCA model.The results showed that MAE-HPLC/DAD method was simple,efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra(Thunb.),which could provide more reliable and precise information for quality evaluation.

Quantitative Analysis and Chemical Fingerprint Similarity for Quality Control of the Seeds of Paeonia suffruticosa Andr. by HPLC

According to the General Office of the State Council of China, tree peony seeds（TPSs, Paeonia suffruticosa Andr.） are considered an emerging source for edible oil. In Chinese folk medicine, TPSs are used for alleviating waist and leg pain. In the present study, a simple, accurate and rapid fingerprint method based on high performance liquid chromatography with diode array detection（HPLe-DAD） was developed and validated to quantify the profiles of ten representative compounds in TPSs. All standard calibration curves exhibited good linearity（R2〉0.9995） in the I-IPLC-DAD analysis. The recovery of the standards ranged from 96.37% to 102.10%. The results show that stilbe- noids are the major constituents in TPSs, and their total content ranges from 25.71 mg/g to 54.03 mg/g. Suffruticosol A, suffruticosol B, trans-e-viniferm, ampelopsin E and paeoniflorin are the major components in methanol- water（80：20, volume ratio） extracts with average contents of 3.962, 12.264, 5.826, 14.060 and 12.755 rag/g, respec- tively. Additionally, 14 batches of seeds collected from different regions were used to establish a reference fingerprint Their similarity values were higher than 0.944 except for the sample（0.863） from Linxia. These results collectively indicate that the quantitative HPLC fingerprint method can serve as a prerequisite quality control for TPSs, and is a promising resource for developing new herbal or food products.