Effect of Different Drying Methods on Volatile Components in Pseudostellariae Radix Based on GC-IMS / 中国实验方剂学杂志

ObjectiveTo compare the effects of different drying methods on volatile components of Pseudostellariae Radix. MethodThe samples were dried by different methods， including air drying， sun drying， hot air drying （40， 60， 80 ℃） and vacuum freeze drying. Gas chromatography-ion mobility spectrometry （GC-IMS） was used to compare the changes of volatile components in the samples after different treatments. The samples were incubated at 80 ℃ and 500 r·min-1 for 15 min， the injection temperature was 85 ℃， the injection volume was 200 μL， the flow rate of carrier gas was from 2 mL to 150 mL during 20 min， and the temperature of IMS detector was 60 ℃. SE-54 capillary column （0.32 mm×30 m， 0.25 μm） was used， the column temperature was 60 ℃， and the analysis time was 35 min. The differential spectra of volatile components were constructed and analyzed by principal component analysis （PCA）. ResultA total of 37 volatile components were identified from dried Pseudostellariae Radix. The number of compounds in descending order was ketones， aldehydes and alcohols. There were some differences in the volatile components in samples dried by different methods. And the volatile components in samples with sun drying， air drying and hot air drying at 40 ℃ were similar， compared with other drying methods， vacuum freeze drying and hot air drying at 80 ℃ had great effects on the volatile components of Pseudostellariae Radix， and the compounds in the samples with vacuum freeze drying were the least. ConclusionIn this study， GC-IMS for the detection and analysis of volatile components in Pseudostellariae Radix is established， which has the characteristics of high efficiency， nondestructive inspection and simple sample processing. This method can be used for the distinction of Pseudostellariae Radix dried by different methods. And hot air drying at 40 ℃ can effectively retain the volatile components of Pseudostellariae Radix， and achieve similar flavor to samples with sun drying and air drying.

GC-IMS Analysis of Volatile Components in Rhododendri Mollis Flos at Different Flowering Stages / 中国实验方剂学杂志

Objective:The volatile components of Rhododendri Mollis Flos were determined and the differences of volatile components at different flowering stages were compared and analyzed. Method:Gas chromatography-ion mobility spectrometry （GC-IMS） was used to detect the volatile components in Rhododendri Mollis Flos at different flowering stages （bud stage， initial flowering stage， half-flowering stage， blooming stage and late blooming stage）. GC-IMS spectra combined with cluster analysis， principal component analysis （PCA） and orthogonal partial least squares-discriminant analysis （OPLS-DA） were used to compare the differences and similarities of volatile components in different flowering stages. Result:A total of 70 volatile components in Rhododendri Mollis Flos at different flowering stages were detected， among which 67 were common components， and 47 were identified qualitatively， mainly alcohols， esters and aldehydes. Carveol was a special component at the late blooming stage. The content of alpha-terpineol is the highest at the initial flowering stage， but not at the blooming stage and late blooming stage. The relative contents of the active ingredients ［6-methyl-5-hepten-2-one， nonanal， alpha-terpineol， 1，8-cineole， linalool oxide， 1-octen-3-ol， （<italic>E</italic>）-3-hexenol］ showed a decreasing trend during flowering stages. GC-IMS spectra showed that the samples at different flowering stages had their own characteristic peak regions， and also had common regions. The results of cluster analysis， PCA and OPLS-DA all showed that the samples at different flowering stages were distinguishable. OPLS-DA was used to screen 19 different components to distinguish different flowering stages， including <italic>γ</italic>-butyrolactone， 1，8-cineole， ethyl hexanoate， etc. Conclusion:Rhododendri Mollis Flos samples at different flowering stages can be distinguished obviously， and the active substances in the volatile components are gradually dissipated with the degree of flower opening， which can provide reference for the improvement of material basis and the study of different flowering stages of Rhododendri Mollis Flos.

Effect of Different Hot Air Drying Methods on Chemical Constituents of Trichosanthis Fructus / 中国实验方剂学杂志

Objective:To compare the effects of different drying methods on the chemical constituents of Trichosanthis Fructus. Method:Trichosanthis Fructus was dried by means of air drying， sun drying， hot air drying （40， 60， 80 ℃） and variable temperature drying （50-80， 80-50 ℃）. The contents of nucleosides and flavonoids in Trichosanthis Fructus peels and seeds treated by different methods were compared by high performance liquid chromatography （HPLC）， mobile phase was acetonitrile-0.2% acetic acid aqueous solution （3∶7） （A）-acetonitrile （B） for gradient elution （0-15 min， 97-95%B； 15-30 min， 95%-90%B； 30-35 min， 90%-87%B； 35-40 min， 87%-86.5%B； 40-48 min， 86.5%-97%B； 48-50 min， 97%B）， the detection wavelength was 260 nm， and the flow rate was 0.4 mL·min^-1. Gas chromatography-ion mobility spectrometry （GC-IMS） was used to compare the changes of volatile components in the samples treated by different treatments. The volatile components were incubated on a SE-54 capillary column （0.32 mm×30 m， 0.25 μm） at 80 ℃ and 500 r·min^-1 for 15 min， the injection temperature was 85 ℃， the injection volume was 400 μL， the analysis time was 35 min， carrier gas was high purity nitrogen， the flow rate of carrier gas was 2.0 mL·min^-1， the flow rate of drift gas was 150 mL·min^-1， and the temperature of IMS detector was 45 ℃. Result:The contents of uridine， adenosine and adenine were higher after hot air drying at >50 ℃. Low temperature drying was conducive to maintaining the stability of cytidine， cytosine， rutin， luteolin and 2ʹ-deoxyadenosine. GC-IMS technology could realize the analysis and identification of Trichosanthis Fructus samples after different treatments. There were more volatile components after hot air drying at 80 ℃ and variable temperature drying. Conclusion:Hot air drying at 40 ℃ and 60 ℃ can retain nucleosides and flavonoids， and the volatile components are similar to those in traditional drying methods， which has the advantages of high efficient， controllable and suitable for industrial production.