Determination of sulfur dioxide residues in sulfur fumigated Chinese herbs with headspace gas chromatography / 药学学报

This paper aims to establish a method for the determination of sulfur dioxide in sulfur fumigation Chinese herbs. Sample powder and hydrochloric acid solution were isolated by paraffin layer in order to avoid early reactions, with the generation of sulfur dioxide, headspace with airtight needle was used to transfer sulfur dioxide into gas chromatograph, and detected with thermal conductivity detector. The analytical performance was demonstrated by the analysis of 12 herbs, spiked at four concentration levels. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) within 15%, were obtained. The limit of detection (LOD) was below 10 mg x kg(-1). Standard addition can be used for low recovery samples. The method is simple, less time-consuming, specific and sensitive. Methods comparison revealed that gas chromatography is better than traditional titration in terms of method operability, accuracy and specificity, showing good application value.

Quantitative analysis and HPLC specific chromatogram of Centellae Herba and its total glucosides by chiral mobile phase additives / 中草药

Objective: To separate the isomers of madecassoside in Centellae Herba and its total glucosides, determine madecassoside and asiaticoside in them, and establish an HPLC specific chromatogram for Centellae Herba total glucosides by using β-cyclodextrin as mobile phase additives. Methods: The Dikma Diamonsil™ C18 column (250 mm x 4. 6 mm, 5 μm) was served as analytical column and acetonitrile-2 mmol/L β-cyclodextrin (24 : 76) as mobile phase at a flow rate of 1. 0 mL/min, the detection wavelength was 205 nm and column temperature was 30°C. Theoretical plate number of asiaticoside was over 4 000. Results: The isomers in Centellae Herba and its total glucosides were separated with the additives of β-cyclodextrin, meeting the requirements of quantitative analysis. In which, madecassoside and asiaticoside showed a good linearity in the range of 0.181-18. 1 μg (r=0. 999 98) and 0.195-19. 5 μg (r=0. 999 98) each. The mean recovery of madecassoside and asiaticoside in Centellae Herba was 101. 2% and 101. 6% (n=9), and that of its 11 batches of total glucosides was 100. 3% and 99. 3%, respectively. Under the qualitative conditions, the six common peaks in HPLC specific chromatogram of its 11 batches of total glucosides could be used as marker peaks for qualitative identification. Conclusion: The analytical method is proved to be convenient and accurate, which can be used for the quality control of Centellae Herba and its total glucosides.

Simultaneous determination of 56 organochlorine and pyrethroid pesticides in traditional Chinese medicines by GC coupled with dual-tower and dual-column / 药学学报

The paper is to report the establishment of a method for the determination of multi-residue organochlorine and pyrethroid pesticides in traditional Chinese medicines (TCMs). Fifty-six pesticides were extracted by high-speed homogenization, and then purified through gel permeation chromatography (GPC) and solid phase extraction (SPE) cartridges. The residues were simultaneously identified and quantified by GC-ECD equipped with dual tower, dual column and two micro-ECD detectors. The analytical performance was demonstrated by the analysis of 3 TCMs samples' extracts, spiked at three concentration levels for each pesticide. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) better than 15%, were obtained. The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg kg(-1). The method had good extraction efficiency, purification effect and good reproducibility, which could be applied to the determination of organochlorine and pyrethroid pesticide residues in the routine analysis of TCMs.