A rapid, accurate and precise method for the determination of sudan I-IV in chili products using on-line solid phase extraction and LC-MS has been developed. Chili products were extracted with acetone and the analytes were cleaned up and enriched on an SPE column (C18, 15–40 µm) through on-line SPE. Chromatographic separation was performed on a C18 analytical column (2.1 × 150 mm, 3 µm) with gradient elution programming of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. All four sudan dyes were separated in less than 8 min. Using in-house validation data, linearity coefficients of determination (R2) of more than 0.9997 were obtained. The limits of detection (LOD) and limits of quantitation (LOQ) for sudan I, II and IV were 0.03 and 0.05 mg kg?1, respectively, and 0.04 and 0.1 mg kg?1 for sudan III. The intra- and inter-day recoveries of the four sudan dyes in chili powder were between 90.1–101.6% and 90.2–102.0%, respectively, with relative standard deviation (RSD) between 0.014–0.164% and 0.011–0.202%, respectively. Therefore, this proposed method could be an alternative assay for the determination of sudan I-IV in chili products due to its rapidness, sensitivity, less sample and solvent consumption. 相似文献
A high performance liquid chromatograph (HPLC)was interfaced to an atmospheric drift tube ion mobility time of flight mass spectrometry. The power of multidimensional separation was demonstrated using chili pepper extracts. The ambient pressure drift tube ion mobility provided high resolving powers up to 166 for the HPLC eluent. With implementation of Hadamard transform (HT), the duty cycle for the ion mobility drift tube was increased from less than 1% to 50%, and the ion transmission efficiency was improved by over 200 times compared with pulsed mode, improving signal to noise ratio 10 times. HT ion mobility and TOF mass spectrometry provide an additional dimension of separation for complex samples without increasing the analysis time compared with conventional HPLC.
A method for determining a group of endocrine-disrupting compounds in water samples was developed. This method was based on high-performance liquid chromatography-(electrospray) mass spectrometry (HPLC-(ESI)MS), working in negative ionization (NI) mode. Solid-phase extraction (SPE) with 200 mg Lichrolut EN was used to preconcentrate the water samples. The performance of the method was tested with several environmental water samples such as river, marine and influent and effluent water from a sewage treatment plant (STP). The limits of detection (LODs) of the method were between 0.001 and 0.3 g L–1 under selective-ion monitoring (SIM) acquisition mode for 500 mL of river, marine and STP effluent water samples and between 0.01 and 3 g L–1 for 100 mL of STP influent water. We determined some endocrine disruptors, such as diuron, bisphenol A (BPA), estrone, 4-tert-butylphenol (4-t-BP), 4-tert-octylphenol (4-t-OP) and pentachlorophenol (PCP), in several water samples at levels of g L–1. 相似文献
A novel method for separation and on-line characterization of flavonoids from Asparagus officinalis by medium-pressure liquid chromatography coupled to electrospray ionization multi-stage mass spectrometry (MPLC-ESI-MSn) was successfully established. The hyphenation between MPLC and ESI-MSn was designed to keep the split ratio exactly in the range from 1:100 to 1:300. The separation procedure was guided by the chromatogram of ion current of MSn and the structures of compounds were characterized by fragments information at the same time. Consequently, it was proved that MPLC coupled with ESI-MSn was an effective method for separation of compounds from multi-component mixtures with high purity and desired amounts and simultaneous elucidation of chemical structures.
