Search

The volatile components in modified polysulfide rubber were analyzed by headspace-gas chromatography-mass spectrometry. The sample amount, injection volume, inlet temperature of gas chromatography (GC) conditions were optimized using the orthogonal test method, and the equilibrium temperature and equilibrium time of the headspace (HS) sampling were optimized. The results showed that under such GC conditions as sample amount of 0.1 g, injection volume of 1.0 mL, the inlet temperature of 250 °C, using such HS conditions as equilibrium temperature of 90 °C, equilibrium time of 20 min, and combination of NIST MS Library search and literature retrieva, 4 kinds of volatile compounds, which recognized as the thiirane, mercaptoethanol, two butyl ether and dibutyl phthalate were idetified. Using ethylene glycol as the internal standard, the 4 kinds of main volatile components relative content of the modified polysulfide rubber products from 6 different production conditions were located in 0 // 3. 633 1 mg/g with the relative standard error (RSD) was 2.52% // 6. 56%. This method had good repeatability. [ABSTRACT FROM AUTHOR]

Dependent component analysis (DCA) was applied to directly estimate source spectral profiles from IR spectra of synthetic mixtures and characterize processing batch for preparation of radix scutellariae. The results show that DCA can estimate information of dependent components (DCs) from the measured infrared spectral (IR) signal obtained during the processing batch for preparation of radix scutellariae, and the estimated information of DCs is corresponding to the IR features of the active components of scutelliare; by inspection of the change trends of the estimated DCs, the endpoint of the processing batch was determined as 55 min. The proposed approach provides a novel way for process analysis and endpoint determination of procedure for preparation of scutellariae.

The additives were abstracted from the manganese dioxide products with four kinds of organic solvents, ether, acetone, chloroform and toluene. The extracts were then baked and their attenuated total reflectance (ATR) FTIR spectra were measured using liquid membrane method. The number of chemical components of the additives was determined by median absolute deviation (MAD), and the spectral information of the pure component was extracted by kernel independent component analysis (KICA). The extracted spectral information of the additives is accordant to that of the practically used compounds. An adaptive kernel independent component analysis (AKICA) was proposed for directive extraction of spectral information from chemical mixtures. The results demonstrated that the AKICA method provides an alternative approach to extracting spectral information from the chemical mixtures without previously chemical or physical preseparation for direct extracting spectral information of pure components in the mixed system.