Simultaneous Qualitative and Quantitative Study of Main Compounds in Commelina communis Linn. by UHPLC-Q-TOF-MS-MS and HPLC-ESI-MS-MS.
This study reported the identification and determination of the main components of Commelina communis Linn. A total of 62 compounds were identified in C. communis Linn. extract, which included 29 flavonoids and flavonoid glycosides, 17 phenolic acids, 4 alkaloids, 1 pyrimidine alkaloids, 3 sterols and 8 fatty acids and others by ultra high performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry. Moreover, a specific, simple, rapid and sensitive high performance liquid chromatography with tandem mass spectrometry method was developed and validated for determination of 13 components of C. communis Linn., which included orientin, iso-orientin, vitexin, isovitexin, rutin, apigenin, protocatechuate, vanillic acid, caffeic acid, ferulic acid, luteolin, quercetin and isorhamnetin. All calibration curves showed good linearity (r ≥ 0.9991) within the test range. The intra- and inter-day precisions (relative standard deviation%, RSD%) were within 1.04 and 0.92%, and the recoveries ranged from 98.64 to 100.8%. These results may contribute to the further study and quality control for C. communis Linn.
Identification of chemical constituents in Ophiocordyceps xuefengensis sp. nov. by HPLC-Q-TOF-MS/MS
Objective Using the HPLC-Q-TOF-MS/MS to analyze and identify the main components in the ethanol extract of Ophiocordyceps xuefengensis sp. nov. Methods The ethanol extract of O. xuefengensis sp. nov. was preparaed by using the ultrasonic methods, the main components in the extracts were separated by using the gradient elution method with RP-HPLC, Yuexu AQ-C18 column(250 mm × 4.6 mm, 5 μm); The positive and negative electro spray ionization(ESI) source was used for determine the chromatographic effluent, the main chromatographic peaks are assigned by Q-TOF. Results Based on the standards of MS/MS and compared with the reference results, 28 compounds, containing mannitol, adenosine, ergosterol, sitosterol, amino acid, fatty acid, and sugar, were identified. Conclusion HPLC-ESI-TOF-MS/MS method can qualitatively analyze the main components in O. xuefengensis sp. nov. from the retention time, UV spectrum, precious relative molecular weight, formula, secondary fragment ions, and so on. It is an effective and fast analysis method for determining the active compounds in O. xuefengensis sp. nov.
Two new organic reference materials for delta13C and delta15N measurements and a new value for the delta13C of NBS 22 oil.
Analytical grade L-glutamic acid is chemically stable and has a C/N mole ratio of 5, which is close to that of many of natural biological materials, such as blood and animal tissue. Two L-glutamic acid reference materials with substantially different 13C and 15N abundances have been prepared for use as organic reference materials for C and N isotopic measurements. USGS40 is analytical grade L-glutamic acid and has a delta13C value of -26.24 per thousand relative to VPDB and a delta15N value of -4.52 per thousand relative to N2 in air. USGS41 was prepared by dissolving analytical grade L-glutamic acid with L-glutamic acid enriched in 13C and 15N. USGS41 has a delta13C value of +37.76 per thousand and a delta15N value of +47.57 per thousand. The delta13C and delta15N values of both materials were measured against the international reference materials NBS 19 calcium carbonate (delta13C=+1.95 per thousand ), L-SVEC lithium carbonate (delta13C=-46.48 per thousand ), IAEA-N-1 ammonium sulfate (delta15N=0.43 per thousand ), and USGS32 potassium nitrate (delta15N=180 per thousand ) by on-line combustion continuous-flow and off-line dual-inlet isotope-ratio mass spectrometry. Both USGS40 and USGS41 are isotopically homogeneous; reproducibility of delta13C is better than 0.13 per thousand, and that of delta15N is better than 0.13 per thousand in 100-microg amounts. These two isotopic reference materials can be used for (i) calibrating local laboratory reference materials, and (ii) quantifying drift with time, mass-dependent fractionations, and isotope-ratio-scale contraction in the isotopic analysis of various biological materials. Isotopic results presented in this paper yield a delta13C value for NBS 22 oil of -29.91 per thousand, in contrast to the commonly accepted value of -29.78 per thousand for which off-line blank corrections probably have not been quantified satisfactorily.