Object A novel microwave-heated extraction (MHE) method was studied for the extraction of glycyrrhizic acid from Glycyrrhiza uralensis Fisch. Methods Several factors, such as temperature, time and microwave power were investigated and the appropriate MHE conditions were obtained from the orthogonal test. Under the optimum conditions, the optimal solvent was selected and the MHE was compared with ultrasonic extraction, leaching at room temperature and Soxhlet extraction,. Results The optimum conditions of MHE is extracting for another 40 min in 0.5% ammonia water after heated to 60 ℃ by microwave of 2 000 W. Yield of glycyrrhizic acid was about equal to that of Soxhlet extraction for 4 h, and that of leaching at room temperature for 44.3 h. Conclusion The MHE method is fast, efficient, energy-saving and high-selective, which is recommendable to the application to active compounds extraction from Chinese herbal medicines.

A rapid and sensitive method for the determination of trace carbaryl in water by using diallyl phthalate-europium ( Eu3+) as fluorescent probes was developed. The interaction between Eu3+ and diallyl phthalate and carbaryl was studied by high resolution mass spectrum, and the fluorescence spectra change of complexes before/after binding with carbaryl was also investigated. The influence factors of fluorescence intensity including solution pH and interferent were studied. The results showed that two diallyl phthalate molecules were complexed with one Eu3+to form stable complexes. Carbaryl could also interact with the probe to form multiple complexes, which significantly increased the fluorescent efficiency of the probe. At pH 9. 0 of solution and by using 245/615 nm as excitation/emission wavelength, the fluorescence intensity showed good linear relationship with the carbaryl concentration ranged from 6. 25í10-8 mol/L to 2. 50í10-6 mol/L, and the linear correlation coefficient was 0. 9968. The detection limit of the method was 9. 6í10-9 mol/L. Water samples were extracted by acetonitrile, and then detected by europium ( Eu3+)-diallyl phthalate fluorescent probe. The recovery of the method was 91. 8%-94. 5%, while RSD was within 6. 1%. The method is suitable for the rapid determination of carbaryl in water samples.

Mammal metallothionein(MT) folds into two separate domains that exhibit different structure and metal binding propertity independently, the study of the strategy of metal ions binding with MT would give better understanding of their exact biological functional mechanisms. In this study, a method using eletrospray ionization mass spectrometry (ESI-MS) phase liquid chromatography and identified by ESI-MS. Different amounts of Cd or Cu were then added in MT-2a samples and ESI-MS was employed to determine the mass difference of MT in different samples. The results Cd2+4S11; while Cd is attached in separate binding sites for the formation of Cd2+3S9 cluster, which intermediately formed with five and six Cd ions were detected. For the Cuprous ions, it prefers to cooperatively bind in β-domain with the form of Cu4-MTβ. The binding form in β-domain would convert from Cu4 into more Cu binding form with the addition of Cu. When high concentration of Cu was added in samples, the result suggested that

A method for the determination of seven kinds of thiocarbamate herbicides, molinate, pebulate, vernolate, triallate, thibencarb, eradicane and butylate in black tea and green tea has been developed. After homogenization, 2.0 g tea sample was soaked with 6 mL water for 1 h. 2.5 g NaCl was then added, and the sample was extracted twice by 20 mL acetonitrile. After concentration, the extract was put through HLB column and eluted by 3 mL acetonitrile. The eluate was then concentrated and dissolved with 2.0 mL hexane-acetone (7∶ 3, V/V) mixture. The preparation was cleaned by Envi-Carb column and eluted with 5 mL hexane-acetone. After concentration, the residue was dissolved by acetonitrile-water (5∶ 5, V/V) solution. Detection was achieved by electrospray ionization(ESI) in positive mode using multiple reaction monitoring. D_3-carbaryl was used as the internal standard, the linear range for the herbicides was 0-200 μg/L and the limit of detection were from 0.093 to 1.77 μg/L, with the correlation coefficients(r) varying from 0.9954 to 0.9988. The recoveries of all thiocarbamate herbicides were from 77.3% to 91.5% at the spiked levels of 5-20 μg/kg. The RSD of each compound was less than 15%. Black tea and green tea samples were successfully analyzed by the proposed method with satisfactory results.

A method for rapid determination of semicarbazide in water by hydrophilic interaction chromatography-quadrupole / electrostatic field orbitrap high resolution mass spectrometry was developed. The sample was extracted with acetonitrile after 0. 1 mol/ L NaOH was added in the sample and then excessive amounts of Na2 SO4 was added to stratify acetonitrile from the mix solution. The acetonitrile extraction solution was dehydrated with anhydrous sodium sulfate. The preparation was separated by an amide column using as hydrophilic interaction column, and gradient elution program was employed by using water and acetonitrile containing 0. 1% formic acid as mobile phase, then it was detected in positive and selected ion monitoring mode by a quadrupole / electrostatic field orbitrap high resolution mass spectrometry. Internal standard method was used for quantitative analysis. The linear correlation coefficient of semicarbazide was 0. 997 in the concentration range of 0. 2 -20 μg / L under the optimal conditions. The limit of detection was 0. 09 μg / L, while the limit of quantitation was 0. 30 μg / L. The recoveries were 82. 3% to 92. 0% , and the relatively standard deviations were less than 7. 6% at the spiked levels of 0. 5, 1. 0 and 5. 0 μg / L using river water and sea water as blank samples. The developed method is suitable for the analysis of trace semicarbazide in environment water samples.