An automated on-line SPE and innovative fast polarity switch bioanalysis method employing dual-gradient liquid chromatography (DGLC) coupled with mass spectrometry (DGLC-MS/MS) was established and validated for the simultaneous determination of ferulic acid, ligustrazine and ligustilide in rat plasma after administration of Rhizoma Chuanxiong, Angelica sinensis extract or monomer. The proteins in plasma samples were precipitated using acetonitrile: methanol (1:1, v/v). Sulfamethoxazole was used as an internal standard. The DGLC system contains two high-pressure pumps. The first pump was used for on-line solid phase extraction with a Cyclone™ SPE column. Chromatographic separations were performed with the other pump on a Syncronis C18 rapid analytical column. The analytical column was eluted by a gradient program that featured an acetonitrile/methanol/water gradient (flow-rate, 0.4ml/min). DGLC afforded greater convenience for bioanalysis. All analytes were simultaneously monitored in positive- and negative-ion mode by SRM (selective reaction monitoring) using the fast polarity switch speed of TSQ Vantage™. Method validation of the assay was implemented. No significant matrix effect was observed. The LLOQ of all analytes were <1.0ng/ml. The precision, recovery and linearity of the analysis met the pre-established requirements. The method was applied to the pharmacokinetics of ferulic acid, ligustrazine and ligustilide in Rhizoma Chuanxiong or Angelica sinensis extracts or monomers.
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http://dx.doi.org/10.1016/j.jpba.2013.08.038 | DOI Listing |
ACS Appl Mater Interfaces
November 2024
International Joint Laboratory of New Textile Materials and Textiles of Henan Province, Zhongyuan University of Technology, Zhengzhou 450007, People's Republic of China.
Adv Mater
September 2024
Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
Responsive materials and actuators are the basis for the development of various leading-edge technologies but have so far mostly been designed based on polymers, incurring key limitations related to sensitivity and environmental tolerance. This work reports a new responsive material, laser-printed carbon film (LPCF), produced via direct laser transformation of a liquid organic precursor and consists of graphitic and amorphous carbons. The high activity of amorphous carbon combined with the dual-gradient structure enables the LPCF to have a actuation speed of 9400° s in response to the stimulus of organic vapor.
View Article and Find Full Text PDFSmall
October 2023
Hong Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, 999077, China.
Rapid detachment of impacting droplets from underlying substrate is highly preferred for mass, momentum, and energy exchange in many practical applications. Driven by this, the past several years have witnessed a surge in engineering macrotexture to reduce solid-liquid contact time. Despite these advances, these strategies in reducing contact time necessitate the elegant control of either the spatial location for droplet contact or the range of impacting velocity.
View Article and Find Full Text PDFJ Chromatogr A
October 2022
Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
Previous studies on stationary phase gradients have inspired a new phase of theoretical work and an expansion of the concept to include multiple retention mechanisms. The theoretical work presented here corroborates previous reports that a stationary phase gradient can produce selectivity in a separation as effectively as careful adjustments to a mobile phase gradient program, especially when such column is operated in mobile phase gradient elution mode. In reality, no column is singularly based on one type of interaction mechanism, and many columns are nowadays designed to solicit multiple solute to stationary phase interactions.
View Article and Find Full Text PDFAdv Mater
January 2022
Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
Electronic skin can detect minute electrical potential changes in the human skin and represent the body's state, which is critical for medical diagnostics and human-computer interface development. On the other hand, sweat has a significant effect on the signal stability, comfort, and safety of electronic skin in a real-world application. In this study, by modifying the cation and anion of a poly(ionic liquid) (PIL) and employing a spinning process, a PIL-based multilayer nanofiber membrane (PIL membrane) electronic skin with a dual gradient is created.
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