More accurate matrix-matched quantification using standard superposition method for herbal medicines.

Various analytical technologies have been developed for quantitative determination of marker compounds in herbal medicines (HMs). One important issue is matrix effects that must be addressed in method validation for different detections. Unlike biological fluids, blank matrix samples for calibration are usually unavailable for HMs.

The evaluation and implementation of Direct Analysis in Real Time quadrupole time-of-flight tandem mass spectrometry for characterization and quantification of geniposide in Re Du Ning Injections.

Rationale: The Direct Analysis in Real Time (DART) ionization source coupled with a quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) system has the capability to desorb analytes directly from samples from complex Chinese herbal preparations without sample cleanup or chromatographic separation.

Methods: In this work, a method based on DART/Q-TOF MS/MS has been developed for rapid determination of geniposide present in 'Re Du Ning Injections', a Chinese herbal preparation. The method has been evaluated for both qualitative and quantitative analysis of geniposide in Re Du Ning Injections.

Rapid analysis of constituents of Radix Cyathulae using hydrophilic interaction-reverse phase LC-MS.

A hydrophilic interaction chromatography (HILIC) and reverse-phase liquid chromatography (RPLC) coupled with electrospray TOF MS method was developed for the analysis and characterization of constituents in the radix of Cyathula officinalis Kuan. Separation parameters of HILIC such as buffer pH, mobile phase strength, and organic modifier were evaluated. Fructose, glucose, and sucrose were identified by HILIC-ESI/TOF MS.

Sensitive determination of 20(S)-protopanaxadiol in rat plasma using HPLC-APCI-MS: application of pharmacokinetic study in rats.

20(S)-Protopanaxadiol (PPD), the main metabolite of protopanoxadiol type ginsenosides (e.g. Rg3 and Rh2), is a very promising anti-cancer drug candidate.

Identification and quantification of 32 bioactive compounds in Lonicera species by high performance liquid chromatography coupled with time-of-flight mass spectrometry.

Flos Lonicerae, referred to the flower buds of several medicinal Lonicera species, is a commonly used traditional Chinese herbal medicine. A multi-component-assay quality control method, using high performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (HPLC-ESI/TOF MS), has been developed for the simultaneous identification and quantification of 32 bioactive compounds in Flos Lonicerae. The limits of detection (LOD) and quantification (LOQ) were in the range of 0.

[Study on the extraction recovery of ginsenoside Re in plasma by different solid-phase cartridges].

Objective: To optimize the solid-phase extraction method by comparison of the extraction recovery of ginsenoside Re plasma samples.

Method: After extracted by different solid-phase cartridges with water, acetonitrile, and different content methanol elution, the plasma samples were analyzed on an Zorbax SB-C18 column with acetonitrile-water gradient elution. From the recovery achieved, the best solid phase cartridge was found.

[Pharmacokinetics of oxymatrine and its metabolite in beagle dogs by LC-MS].

Objective: To establish LC-MS method in the determination of oxymatrine and its metabolite in plasma and investigate their pharmacokinetics in beagle dogs.

Method: Lichrospher C18 column (4.6 mm x 250 mm, 5 microm) was used as the analytical column maintained at 25 degrees C.

[Analysis of impurity in caderofloxacin].

Aim: To analyse the main impurity of caderofloxacin.

Methods: The impurity of caderofloxacin was analysed and determinated by RP-HPLC/ESI/MS with a Zorbax SB-C18 (150 mm x 4.6 mm ID, 5 microns) column.

[Study on the fingerprints of the alkaloids in Sophora flavescens].

Objective: To establish a method for HPLC fingerprint determination of the alkaloids in S. flavescens.

Method: RP-HPLC, linear gradient elution, LC/MS, etc.

[Analysis of the response factors of different quinolones detected by evaporative light-scattering detector].

Aim: To analyze the response factors of different quinolone antibiotics detected by evaporative light-scattering detector (ELSD).

Methods: The response factors of five different quinolones (enoxacin, levofloxacin, ciprofloxacin, lomefloxacin and gatifloxacin) detected by ELSD were determined by using a YMC-Pack ODS-AM cloumn (150 mm x 4.6 mm ID, 5 microns) as analytical column and 0.

[Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry].

Aim: To determine the molecular weight and first-order structure of somatostatin.

Methods: The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol.

[Study on HPLC fingerprint of the triterpene acids in Poria cocos].

Objective: To establish a method for HPLC fingerprint determination of the triterpene acids in Poria cocos.

Method: RP-HPLC, linear gradient elution and LC/MS, etc. were used to optimize the fingerprint determination method, and identify the main peaks in the HPLC fingerprint.

[Determination of cyclovirobuxine D by RP-HPLC with precolumn fluorescence derivatization].

Aim: To establish a RP-HPLC method for determination of cyclovirobuxine D.

Methods: Cyclovirobuxine D reacted with a derivative reagent 1-naphthyl isocyanate in chloroform to form fluorescence derivatives, stopped the reaction by adding the mobile phase and then directly injected the solution into the chromatograph to seperate it by RP-HPLC. The analysis was carried out on C18 column, the mobile phase is methanol-water (85:15), the excitation wavelength was set at 305 nm, emission at wavelength 385 nm, and the flow rate was 1 mL.

[Impurity analysis and their structure determination of gatifloxacin].

Aim: To analyse the impurities of gatifloxacin.

Methods: The impurity of gatifloxacin were analysized and determinated by RP-HPLC/electrospray ionization mass spectrometry with a Zorbax SB-C18(4.6 mm x 150 mm ID, 5 microns).