Application And Research In Quality Control Of Herbal Medicines By Direct Spray Mass Spectrometry

The ambient mass spectrometry is a direct, fast and low-costing analytical technique. The advantage of this technology is that the complex sample can be analyzed directly without pre-treatment. The direct spray mass spectrometry is simple, easy to operate and less solvent- consuming technique. In recent years, the direct spray mass spectrometry was applied in the analysis of environmental samples, foodstuffs, drugs, and public safety et al. However, no sample preprocessing will lead an important influence on target compounds because of complex matrix. Therefore, this paper used silane reagent to modify the paper used in paper spray. The effect of hydrophobicity of paper matrix on the sensitivity and selectivity of paper spray MS has been investigated. The main research contents are as followed:(1) Analysis of ginkgolic acids with direct spray mass spectrometry. This paper established a new method of analysis, which analyzed and researched the content and distribution in seven parts tissues of Ginkgo biloba and their extracts. Specifically, in negative ion mode, results based on the signal strength ratio of Ginkgo acid and salicylic acid of quantitative showed us the semi-quantitative detection towards 3 Ginkgo acids was reasonable. The method showed good linear coefficients in the range of 0.2000-10.00 mg·L-1 for all analytes. The limit of detection was lower than 0.1 mg·L-1. There was a deviation on quantitative results obtained for paper spray MS and HPLC-UV, but as a semi-quantitative result was feasible. In addition, the new method was simple preprocessing and fast detection, and results can be obtained in short time.(2) Analysis of alkaloids with direct spray mass spectrometry. This paper illustrated a novel method of analysis, which analyzed and researched the content and distribution in five parts tissues of Mecleagua cordata(Willd). Specifically, in positive ion mode, the method showed a good linearity of 0.2-30 mg·L-1 for 4 kinds of alkaloids. The limit of detection was lower than 0.1 mg·L-1. The linear coefficients of analytes were higher than 0.99. The method provides a basis on the distribution of four kinds of alkaloids in Mecleagua cordata(Willd). The results have a certain reference value for the researchers in this field.(3) Effect of hydrophobicity of paper on paper spray MS. The paper was modified by different groups, i.e. C18, C10, C1. Different compounds such as organic acids, organic amines, amino acids were detected by paper spray MS on the different modified paper. The results demonstrate that the hydrophobicity of paper matrix affect the sensitivity and selectivity of detection for organic acids significantly. For paper spray, in the positive mode, stable electrospray ionization can occur, and the electrical discharge was always present in the negative-ion mode. However, electrical discharge phenomenon is suppressed by hydrophobic paper. Therefore, hydrophobic paper can improve the efficiency of ionization in negative mode.