ABSTRACT
Objective To identify the chemical constituents of Xiakucao Xiaoliu mixture by high performance liquid chromatography-high resolution time-of-flight mass spectrometry (HPLC-TOF/MS). Methods The chromatographic separation ACE (3.0mm×150 mm) column was used. The mobile phase was methanol (A) and 0.1% formic acid (B). The gradient elution was: 0-5 min, 5% A; 5-10 min, 5%-15% A; 10-30 min, 15%-45%A; 30-40 min, 45%-70%B; 40-50 min, 70%-90%B. The injection volume was 2 μl. The flow rate was 0.4 ml/min. The column temperature was 25°C. The mass spectrometry was characterized by time-of-flight mass spectrometry, using ESI ion source. The common monitoring was in positive and negative ion mode. The reference ion was m/z 121.9856, 1033.9881. The scanning range was m/z 100-1200. Results A total of 37 chemical constituents were identified in the Xiakucao Xiaoliu mixture, 8 in the positive ion mode fragment voltage of 160 V, 28 in the negative ion mode fragment voltage of 160 V, and 19 in the fragment voltage of 260 V. Both positive and negative ions had 4 responses. The negative ion mode has 16 responses under both fragment voltages. And the ingredients were medicinal. Conclusion An effective method for the identification of the chemical constituents of Prunella vulgaris L. by HPLC-TOF/MS was established, which laid a foundation for its quality control and in-depth study in vivo.
ABSTRACT
A high throughput screening method based on QuEChERS purification and stable isotope dilution-liquid chromatography coupled to high resolution time-of-flight mass spectrometry was developed for the simultaneous rapid determination of 86 kinds of glucocorticoids (GCs) in cosmetics.The analytes were extracted by acetonitrile, and then the extracts were purified using an improved QuEChERS method.The chromatographic separation was performed on a novel multiple chromatographic retention mechanisms column of Poroshell 120 PFP (100 mm × 2.1 mm, 2.7 μm) with gradient elution using 0.2% (V/V) acetic acid and acetonitrile as mobile phase.The accurate mass database of parent ions and mass spectra library of fragment ions of 86 GCs were established under positive ionization mode with electrospray ionization source.Based on the method described above, the qualitative identifications of the 86 GCs were accomplished without the contrast of standard substances.The results demonstrated that the linear range of this method was from 2 μg/L to 200 μg/L with good correlation coefficients of R2>0.99.The average recoveries of the 86 GCs ranged from 66.2% to 112.8%, and the relative standard deviation (RSDs) was 4.6%-13.9% at three different spiked levels.The limit of detection (LOD) and quantification (LOQ) were 0.006-0.015 mg/kg and 0.02-0.05 mg/kg, respectively.The method is simple, efficient, reliable and accurate, and is suitable for high throughput screening of 86 GCs added illegally in cosmetics.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis.</p><p><b>METHODS</b>A comprehensive two-dimensional gas chromatography (GC×GC) and high-resolution time-of-flight mass spectrometry (HR-TOF/MS) with colorized fuzzy difference (CFD) method was used to investigate the effect of sulfur-fumigation on the volatile components from Radix Angelicae Sinensis.</p><p><b>RESULTS</b>Twenty-five compounds that were found in sun-dried samples disappeared in sulfur-fumigated samples. Seventeen volatile components including two sulfur-containing compounds were newly generated for the first time in volatile oils of sulfur-fumigated Radix Angelicae Sinensis.</p><p><b>CONCLUSION</b>The strategy can be successfully applied to rapidly and holistically discriminate sun-dried and sulfur-fumigated Radix Angelicae Sinensis. GC×GC-HR-TOF/MS based CFD is a powerful and feasible approach for the global quality evaluation of Radix Angelicae Sinensis as well as other herbal medicines.</p>
Subject(s)
Color , Drugs, Chinese Herbal , Fumigation , Fuzzy Logic , Gas Chromatography-Mass Spectrometry , Methods , Oils, Volatile , Reference Standards , Sulfur , Volatile Organic CompoundsABSTRACT
By using the high resolution mass spectrometer TripleTOF 5600 , three kinds of standard proteins including bovine serum albumin ( BSA) , ovalbumin ( OVA) and lysozyme C( LYZC) were analyzed, and the correlationship between the ion intensity of mass spectrometry and the relative content of protein sample was investigated. The protein samples were digested by trypsion and diluted to 1-1024 fmol in 7 μL. The ion counts per second ( cps) were used to stand for the amounts of proteins and peptides. Then the correlation between sum of ion intensity ( cps) of all the peptides, number of peptides detected and the amount of proteins was investigated. By comparing the change of values of the same sample in three parallel experiments, a linear relationship between these indexes and the amount of proteins within 1-1024 fmol was found when the cps was more than 1000. Usually, the maximal ion intensity was no more than 1. 5 times of the minimum value for same peptide in triplicate experiments, which suggested that the 3 times or more change of ion intensity was the minimum threshold to determine the differences of proteins amounts in different samples. This study provides a relative quantitative analysis method using qualitative data of high resolution and high scan speed mass spectrometry, which can quickly and easily provide reference for biological and medical research.